BroControl ¶

This document summarizes installation and use of BroControl, a tool for operating Bro installations. BroControl has two modes of operation: a stand-alone mode for managing a traditional, single-system Bro setup; and a cluster mode for maintaining a multi-system setup of coordinated Bro instances load-balancing the work across a set of independent machines. Once installed, the operation is pretty similar for both types; just keep in mind that if this document refers to “nodes” and you’re in a stand-alone setup, there is only a single one and no worker/proxies.

Contents

Download ¶

You can find the latest BroControl release for download at http://www.bro.org/download.

BroControl’s git repository is located at git://git.bro.org/broctl. You can browse the repository here.

This document describes BroControl 1.9. See the CHANGES file for version history.

Prerequisites ¶

Running BroControl requires the following prerequisites:

A Unix system. FreeBSD, Linux, and Mac OS X are supported and should work out of the box. Other Unix systems will quite likely require some tweaking.

A version of Python >= 2.6 (on FreeBSD, the package “py27-sqlite3” must also be installed).

A bash (note that on FreeBSD, bash is not installed by default).

If sendmail is installed, then BroControl can send mail (for a cluster setup, it would be needed on the manager only). Otherwise, BroControl will not attempt to send mail.

If gdb (lldb on Mac OS X, which is included with Xcode) is installed and if Bro crashes with a core dump, then BroControl can include a backtrace in its crash report (that can be helpful for debugging problems with Bro). Otherwise, crash reports will not include a backtrace.

For a cluster setup that spans more than one machine, there are additional requirements:

All machines in the cluster must be running exactly the same operating system (even the version must be the same).

Every host in the cluster must have rsync installed.

The manager host must have ssh installed, and every other host in the cluster must have sshd installed and running.

Decide which user account will be running BroControl, and then make sure this user account is set up on all hosts in your cluster. Note that if you plan to run broctl using sudo (i.e., “sudo broctl”), then the user running broctl will be “root” (and in that case the user running sudo does not need to exist on the other hosts in your cluster).

Make sure the user running BroControl can ssh from the manager host to each of the other hosts in your cluster, and this must work without being prompted for anything (one way to accomplish this is to use ssh public key authentication). You will need to try this manually before attempting to run broctl, because broctl uses ssh to connect to other hosts in your cluster.

If you’re using a load-balancing method (such as PF_RING), then there is additional software to install (for details, see the Cluster Configuration documentation).

Installation ¶

Follow the directions to install Bro and BroControl in the Installing Bro documentation. Note that if you are planning to run Bro in a cluster configuration, then you need to install Bro and BroControl only on the manager host (the BroControl install or deploy commands will install Bro and all required scripts to the other hosts in your cluster).

Configuration ¶

Before attempting to run BroControl, you first need to edit the broctl.cfg, node.cfg, and networks.cfg files. All three of these configuration files contain a valid configuration by default, but you might need to customize a few things.

First, edit the node.cfg file and specify the nodes that you will be running. You need to decide whether you will be running Bro standalone or in a cluster. For a standalone configuration, there must be only one Bro node defined in this file. For a cluster configuration, at a minimum there must be a manager node, a proxy node, and one or more worker nodes. There is a Cluster Configuration guide that provides examples and additional information.

Each node defined in the node.cfg file has a set of options. A few options are required to be specified on every node, and some options are allowed only on certain node types (broctl will issue an error if you make a mistake). By default, the node.cfg file contains a valid configuration for a standalone setup and has a valid cluster configuration commented-out. If you want to use the default configuration, then at least check if the “interface” option is set correctly for your system. For a description of every option available for nodes, see the Node section below.

In the broctl.cfg file, you should review the BroControl options and check if any are not set correctly for your environment. The options have default values that are reasonable for most users (the MailTo option is probably the one that you will most likely want to change), but for a description of every BroControl option, see the Option Reference section below.

BroControl options are used in three different ways: some options override the value of a Bro script constant (these are noted in the documentation), some affect only BroControl itself, and others affect Bro.

Finally, edit the networks.cfg file and add each network (using standard CIDR notation) that is considered local to the monitored environment (by default, the networks.cfg file just lists the private IPv4 address spaces).

The information in the networks.cfg file is used when creating connection summary reports. Also, BroControl takes the information in the networks.cfg file and puts it in the global Bro script constant Site::local_nets, and this global constant is used by several standard Bro scripts.

Basic Usage ¶

There are two ways to run BroControl commands: by specifying a BroControl command on the command-line (e.g. “broctl deploy”), or by entering BroControl’s interactive shell by running the broctl script without any arguments (e.g. “broctl”). The interactive shell expects commands on its command-line:

> broctl
Welcome to BroControl x.y

Type "help" for help.

[BroControl] >

As the message says, type help to see a list of all commands. We will now briefly summarize the most important commands. A full reference follows Command Reference.

If this is the first time you are running BroControl, then the first command you must run is the BroControl deploy command. The “deploy” command will make sure all of the files needed by BroControl and Bro are brought up-to-date based on the configuration specified in the broctl.cfg, node.cfg, and networks.cfg files. It will also check if there are any syntax errors in your Bro policy scripts. For a cluster setup it will copy all of the required scripts and executables to all the other hosts in your cluster. Then it will successively start the logger, manager, proxies, and workers (for a standalone configuration, only one Bro instance will be started).

The status command can be used to check that all nodes are “running”. If any nodes have a status of “crashed”, then use the diag command to see diagnostic information (you can specify the name of a crashed node as an argument to the diag command to show diagnostics for only that one node).

If you want to stop the monitoring, issue the stop command. After all nodes have stopped, the status command should show all nodes as “stopped”.

The exit command leaves the shell (you can exit BroControl while Bro is running).

Whenever the BroControl or Bro configuration is modified in any way, including changes to configuration files and site-specific policy scripts or upgrading to a new version of Bro, deploy must be run (deploy will check all policy scripts, install all needed files, and restart Bro). No changes will take effect until deploy is run.

BroControl cron command ¶

The main purpose of the BroControl cron command is to check for Bro nodes that have crashed, and to restart them. The command also performs other housekeeping tasks, such as removing expired log files, checking if there is sufficient free disk space, etc. Although this command can be run directly by a user, it is intended to be run from a cron job so that crashed nodes will be restarted automatically.

For example, to setup a cron job that runs once every five minutes, insert the following entry into the crontab of the user running BroControl (change the path to the actual location of broctl on your system) by running the crontab -e command:

*/5 * * * * /usr/local/bro/bin/broctl cron

It is important to make sure that the cron job runs as the same user that normally runs broctl on your system. For a cluster configuration, this should be run only on the manager host.

Note that on some systems, the default PATH for cron jobs might not include the directory where python or bash are installed (the symptoms of this problem would be that “broctl cron” works when run directly by the user, but does not work from a cron job). The simplest fix for this problem would be to redefine PATH on a line immediately before the line that runs broctl in your crontab.

If the "broctl cron disable" command is run, then broctl cron will be disabled (i.e., broctl cron won’t do anything) until the "broctl cron enable" command is run. To check the status at any time, run "broctl cron ?".

Log Files ¶

Log rotation and archival ¶

While Bro is running you can find the current set of (aggregated) logs in logs/current (which is a symlink to the corresponding spool directory). In a cluster setup, logs are written on the logger host (however, if there is no logger defined in your node.cfg, then the manager writes logs).

Bro logs are automatically rotated once per hour by default, or whenever Bro is stopped. A rotated log is renamed to contain a timestamp in the filename. For example, the conn.log might be renamed to conn.2015-01-20-15-23-42.log.

Immediately after a log is rotated, it is archived automatically. When a log is archived, it is moved to a subdirectory of logs/ named by date (such as logs/2015-01-20), then it is renamed again, and gzipped. For example, a rotated log file named conn.2015-01-20-15-23-42.log might be archived to logs/2015-01-20/conn.15:48:23-16:00:00.log.gz. If the archival was successful, then the original (rotated) log file is removed.

If, for some reason, a rotated log file cannot be archived then it will be left in the node’s working directory. Next time when BroControl either stops Bro or tries to restart a crashed Bro, it will try to archive such log files again. If this attempt fails, then an email is sent which contains the name of a directory where any such unarchived logs can be found.

Log files created only when using BroControl ¶

There are several log files that are not created by Bro, but rather are created only when using BroControl to run Bro.

When BroControl starts Bro it creates two files “stdout.log” and “stderr.log”, which just capture stdout and stderr from Bro. Although these are not actually Bro logs, they might contain useful error or diagnostic information. The contents of these files are included in crash reports and also in the output of the “broctl diag” command.

Also, whenever logs are rotated, a connection summary report is generated if the trace-summary tool is installed. Although these are not actually Bro logs, they follow the same filename convention as other Bro logs and they have the filename prefix “conn-summary”. If you don’t want these connection summary files to be created, then you can set the value of the TraceSummary option to an empty string.

Bro Scripts ¶

Site-specific Customization ¶

If you want to adapt the Bro policy to the local environment, then you will most likely need to write local policy scripts.

Sample local policy scripts (which you can edit) are located in share/bro/site. The file called local.bro gets loaded automatically.

The recommended way to modify the policy is to use only “@load” directives in the local.bro script. For example, you can add a “@load” directive to load a Bro policy script that is included with Bro but is not loaded by default. You can also create custom site-specific policy scripts in the same directory as the local.bro script, and “@load” them from the local.bro script. For example, you could create your own Bro script mypolicy.bro in the share/bro/site directory, and then add a line “@load mypolicy” (without the quotes) to the local.bro script.

After creating or modifying your local policy scripts, you must install them by using the BroControl “install” or “deploy” command. Next, you can use the BroControl “scripts” command to verify that your new scripts will be loaded when you start Bro.

Load Order of Scripts ¶

When writing custom site-specific policy scripts, it can be useful to know in which order the scripts are loaded. For example, if more than one script sets a value for the same global variable, then the value that takes effect is the one set by the last such script loaded. The BroControl “scripts” command shows the load order of every script loaded by Bro.

When Bro starts up, the first script it loads is init-bare.bro, followed by init-default.bro (keep in mind that each of these scripts loads many other scripts). Note that these are the only scripts that are automatically loaded when running Bro directly (instead of using BroControl to run Bro).

The next script loaded is the local.bro script. By default, this script loads a variety of other scripts. You can edit local.bro and comment-out anything that your site doesn’t need (or add new “@load” directives).

Next, the “broctl” script package is loaded. This consists of some standard settings that BroControl needs.

The next scripts loaded are local-networks.bro and broctl-config.bro. These scripts are automatically generated by BroControl based on the contents of the networks.cfg and broctl.cfg files. Also, some BroControl plugins might generate script code that will be automatically inserted into the broctl-config.bro script.

The last scripts loaded are any node-specific scripts specified with the option aux_scripts in node.cfg. This option is seldom ever needed, but can be used to load additional scripts to individual nodes only. For example, one could add a script experimental.bro to a single worker for trying out new experimental code.

Mails ¶

There are several situations when BroControl sends mail to the address given in MailTo (note that BroControl will not be able to send any mail when the value of the SendMail option is an empty string):

When the “broctl cron” command runs it performs various tasks (such as checking available disk space, expiring old log files, etc.). If any problems occur, a mail will be sent containing a list of those issues. In order to reduce the amount of mail, the value of the following options can be changed (see documentation of each option): MailHostUpDown, MinDiskSpace, StatsLogEnable, MailReceivingPackets.
When BroControl tries to start or stop (via any of these commands: start, stop, restart, deploy, or cron) a node that has crashed, a crash report is mailed (one for each crashed node). The crash report is essentially just the output of the “broctl diag” command.
When BroControl stops Bro or restarts a crashed Bro, if any log files could not be archived, then mail will be sent to warn about this problem. This mail can be disabled by setting MailArchiveLogFail=0.
If trace-summary is installed, a traffic summary is mailed each rotation interval. To disable this mail, set MailConnectionSummary=0 (however, the connection summary file will still be created and archived along with all other log files).

Using BroControl as an unprivileged user ¶

If you decide to run BroControl as an unprivileged user, there are a few issues that you may encounter.

If you installed Bro and BroControl as the “root” user, then you will need to adjust the ownership or permissions of the “logs” and “spool” directories (and everything in those directories) so that the user running BroControl has write permission.

If you’re using a cluster setup that spans multiple machines, and if your BroControl install or deploy commands fail with a permission denied error, then it’s most likely due to the user running BroControl not having permission to create the install prefix directory (by default, this is /usr/local/bro) on each remote machine. A simple workaround is to login to each machine in your cluster and manually create the install prefix directory and then set ownership or permissions of this directory so that the user who will run BroControl has write access to it.

Finally, on the worker nodes (or the standalone node), Bro must have access to the target network interface in promiscuous mode. If Bro doesn’t have the necessary permissions, then it will fail almost immediately upon startup. A workaround for this is provided in the Bro FAQ.

Bro communication ¶

This section summarizes the network communication between Bro and BroControl, which is useful to understand if you need to reconfigure your firewall. If your firewall is preventing Bro communication, then either the “deploy” command or the “peerstatus” command will fail.

For a cluster setup, BroControl uses ssh to run commands on other hosts in the cluster, so the manager host needs to connect to TCP port 22 on each of the other hosts in the cluster. Note that BroControl never attempts to ssh to the localhost, so in a standalone setup BroControl does not use ssh.

Each instance of Bro in a cluster needs to communicate directly with other instances of Bro regardless of whether these instances are running on the same host or not. Each proxy and worker needs to connect to the manager, and each worker needs to connect to each proxy. If a logger node is defined, then each of the other nodes needs to connect to the logger.

Note that you can change the port that Bro listens on by changing the value of the “BroPort” option in your broctl.cfg file (this should be needed only if your system has another process that listens on the same port). By default, a standalone Bro listens on TCP port 47760. For a cluster setup, the logger listens on TCP port 47761, and the manager listens on TCP port 47762 (or 47761 if no logger is defined). Each proxy is assigned its own port number, starting with one number greater than the manager’s port. Likewise, each worker is assigned its own port starting one number greater than the highest port number assigned to a proxy.

Finally, a few BroControl commands (such as “print” and “peerstatus”) rely on Broker to communicate with Bro. This means that for those commands to function, BroControl needs to connect to each Bro instance.

Command Reference ¶

The following summary lists all commands supported by BroControl. If not specified otherwise, commands taking [<nodes>] as arguments apply their action either to the given set of nodes, to the manager node if “manager” is given, to all proxy nodes if “proxies” is given, to all worker nodes if “workers” is given, or to all nodes if none are given.

capstats [<nodes>] [<interval>]: Determines the current load on the network interfaces monitored by each of the given worker nodes. The load is measured over the specified interval (in seconds), or by default over 10 seconds. This command uses the capstats tool, which is installed along with broctl.

check [<nodes>]

Verifies a modified configuration in terms of syntactical correctness (most importantly correct syntax in policy scripts).

Note that this command checks the site-specific policy files as found in SitePolicyPath rather than the ones installed by the install command. Therefore, new errors in a policy script can be detected before affecting currently running nodes, even when they need to be restarted.

This command should be executed for each configuration change before using install to put the change into place. However, when using the deploy command there is no need to first run check, because deploy automatically runs check before installing the policy scripts.

cleanup [–all] [<nodes>]

Clears the nodes’ spool directories, but only for nodes that are not running. This implies that their persistent state is flushed. Nodes that were crashed are reset into the “stopped” state.

If --all is specified, this command also removes the content of the node’s TmpDir, in particular deleting any data potentially saved there for reference from previous crashes. Generally, if you want to reset the installation back into a clean state, you can first stop all nodes, then execute cleanup --all, then install, and finally start all nodes again.

config: Prints all configuration options with their current values.

cron [enable|disable|?] | [–no-watch]

This command has two modes of operation. Without arguments (or just --no-watch), it performs a set of maintenance tasks, including the logging of various statistical information, expiring old log files, checking for dead hosts, and restarting nodes which terminated unexpectedly (the latter can be suppressed with the --no-watch option if no auto-restart is desired). This mode is intended to be executed regularly via cron, as described in the installation instructions. While not intended for interactive use, no harm will be caused by executing the command manually: all the maintenance tasks will then just be performed one more time.

The second mode is for interactive usage and determines if the regular tasks are indeed performed when broctl cron is executed. In other words, even with broctl cron in your crontab, you can still temporarily disable it by running cron disable, and then later reenable with cron enable. This can be helpful while working, e.g., on the BroControl configuration and cron would interfere with that. cron ? can be used to query the current state.

deploy

Checks for errors in Bro policy scripts, then does an install followed by a restart on all nodes. This command should be run after any changes to Bro policy scripts or the broctl configuration, and after Bro is upgraded or even just recompiled.

This command is equivalent to running the check, install, and restart commands, in that order.

df [<nodes>]: Reports the amount of disk space available on the nodes. Shows only paths relevant to the broctl installation.

diag [<nodes>]: If a node has terminated unexpectedly, this command prints a (somewhat cryptic) summary of its final state including excerpts of any stdout/stderr output, resource usage, and also a stack backtrace if a core dump is found. The same information is sent out via mail when a node is found to have crashed (the “crash report”). While the information is mainly intended for debugging, it can also help to find misconfigurations (which are usually, but not always, caught by the check command).

exec <command line>: Executes the given Unix shell command line on all hosts configured to run at least one Bro instance. This is handy to quickly perform an action across all systems.

exit: Terminates the shell.

help: Prints a brief summary of all commands understood by the shell.

install [–local]

Reinstalls on all nodes, including all configuration files and local policy scripts.

The --local option is intended for testing or debugging. It causes only the local host to be installed (i.e., no changes pushed out to any other hosts in the Bro cluster). Normally all nodes should be reinstalled at the same time, as any inconsistencies between them will lead to strange effects.

This command must be executed after all changes to any part of the BroControl configuration or after upgrading to a new version of Bro or BroControl, otherwise the modifications will not take effect. Before executing install, it is recommended to verify the configuration with check. Note that when using the deploy command there is no need to first use the install command, because deploy automatically runs install before restarting the nodes.

netstats [<nodes>]: Queries each of the nodes for their current counts of captured and dropped packets.

nodes

Prints a list of all configured nodes.

Note that the env_vars attribute includes the set of environment variables from the ‘env_vars’ option in both ‘node.cfg’ and ‘broctl.cfg’ and also those set by any plugins.

peerstatus [<nodes>]: Primarily for debugging, peerstatus reports statistics about the network connections cluster nodes are using to communicate with other nodes.

print <id> [<nodes>]: Reports the current live value of the given Bro script ID on all of the specified nodes (which obviously must be running). This can for example be useful to (1) check that policy scripts are working as expected, or (2) confirm that configuration changes have in fact been applied. Note that IDs defined inside a Bro namespace must be prefixed with <namespace>:: (e.g., print Log::enable_remote_logging).

process <trace> [options] [– <scripts>]

Runs Bro offline on a given trace file using the same configuration as when running live. It does, however, use the potentially not-yet-installed policy files in SitePolicyPath and disables log rotation. Additional Bro command line flags and scripts can be given (each argument after a -- argument is interpreted as a script).

Upon completion, the command prints a path where the log files can be found. Subsequent runs of this command may delete these logs.

In cluster mode, Bro is run with both manager and worker scripts loaded into a single instance. While that doesn’t fully reproduce the live setup, it is often sufficient for debugging analysis scripts.

quit: Terminates the shell.

restart [–clean] [<nodes>]

Restarts the given nodes, or all nodes if none are specified. The effect is the same as first executing stop followed by a start, giving the same nodes in both cases.

If --clean is given, the installation is reset into a clean state before restarting. More precisely, a restart --clean turns into the command sequence stop, cleanup, check, install, and start.

scripts [-c] [<nodes>]

Primarily for debugging Bro configurations, the scripts command lists all the Bro scripts loaded by each of the nodes in the order they will be parsed by the node at startup. The pathnames of each script are indented such that it is possible to determine from where a script was loaded based on the amount of indentation.

If -c is given, the command operates as check does: it reads the policy files from their original location, not the copies installed by install. The latter option is useful to check a not yet installed configuration.

start [<nodes>]: Starts the given nodes, or all nodes if none are specified. Nodes already running are left untouched.

status [<nodes>]

Prints the current status of the given nodes.

For each node, the information shown includes the node’s name and type, the host where the node will run, the status, the PID, and the date/time when the node was started. The status column will usually show a status of either “stopped” or “running”. A status of “crashed” means that BroControl verified that Bro is no longer running, but was expected to be running.

stop [<nodes>]: Stops the given nodes, or all nodes if none are specified. Nodes that are in the “crashed” state are reset to the “stopped” state, and nodes that are “stopped” are left untouched.

top [<nodes>]: For each of the nodes, prints the status of the Bro process in a top-like format, including CPU usage and memory consumption. If executed interactively, the display is updated frequently until key q is pressed. If invoked non-interactively, the status is printed only once.

update [<nodes>]

NOTE: This command is deprecated and will be removed in a future release.

After a change to Bro policy scripts, this command updates the Bro processes on the given nodes while they are running (i.e., without requiring a restart). However, such dynamic updates work only for a subset of Bro’s full configuration. The following changes can be applied on the fly: The value of all const variables defined with the &redef attribute can be changed. More extensive script changes are not possible during runtime and always require a restart; if you change more than just the values of &redef-able consts and still issue update, the results are undefined and can lead to crashes. Also note that before running update, you still need to do an install (preferably after check), as otherwise update will not see the changes and it will resend the old configuration.

Option Reference ¶

This section summarizes the options that can be set in broctl.cfg for customizing the behavior of BroControl (the option names are not case-sensitive). Usually, one only needs to change the “user options”, which are listed first. The “internal options” are, as the name suggests, primarily used internally and set automatically. They are documented here only for reference.

User Options ¶

BroArgs (string, default _empty_): Additional arguments to pass to Bro on the command-line (e.g. broargs=-f “tcp port 80”).

BroPort (int, default 47760): The TCP port number that Bro will listen on. For a cluster configuration, each node in the cluster will automatically be assigned a subsequent port to listen on.

CommTimeout (int, default 10): The number of seconds to wait before assuming Broccoli communication events have timed out.

CommandTimeout (int, default 60): The number of seconds to wait for a command to return results.

CompressCmd (string, default “gzip -9”): If archived logs will be compressed, the command to use for that. The specified command must compress its standard input to standard output.

CompressExtension (string, default “gz”): If archived logs will be compressed, the file extension to use on compressed log files. When specifying a file extension, don’t include the period character (e.g., specify ‘gz’ instead of ‘.gz’).

CompressLogs (bool, default 1): True to compress archived log files.

ControlTopic (string, default “bro/control”): The Broker topic name used for sending and receiving control messages to Bro processes.

CrashExpireInterval (int, default 0): Number of days that crash directories are kept (zero means never expire).

CronCmd (string, default _empty_): A custom command to run everytime the cron command has finished.

Debug (bool, default 0): Enable extensive debugging output in spool/debug.log.

Env_Vars (string, default _empty_): A comma-separated list of environment variables (e.g. env_vars=VAR1=123, VAR2=456) to set on all nodes immediately before starting Bro. Node-specific values (specified in the node configuration file) override these global values.

HaveNFS (bool, default 0): True if shared files are mounted across all nodes via NFS (see the FAQ).

KeepLogs (string, default _empty_): A space-separated list of filename shell patterns of expired log files to keep (empty string means don’t keep any expired log files). The filename shell patterns are not regular expressions and do not include any directories. For example, specifying ‘conn.* dns*’ will prevent any expired log files with filenames starting with ‘conn.’ or ‘dns’ from being removed. Finally, note that this option is ignored if log files never expire.

LogDir (string, default “${BroBase}/logs”): Directory for archived log files.

LogExpireInterval (string, default “0”): Time interval that archived log files are kept (a value of 0 means log files never expire). The time interval is expressed as an integer followed by one of the following time units: day, hr, min.

LogRotationInterval (int, default 3600): The frequency of log rotation in seconds for the manager/standalone node (zero to disable rotation). This overrides the Bro script variable Log::default_rotation_interval.

MailAlarmsInterval (int, default 86400): The frequency (in seconds) of sending alarm summary mails (zero to disable). This overrides the Bro script variable Log::default_mail_alarms_interval.

MailAlarmsTo (string, default “${MailTo}”): Destination address for alarm summary mails. Default is to use the same address as MailTo. This overrides the Bro script variable Notice::mail_dest_pretty_printed.

MailArchiveLogFail (bool, default 1): True to enable sending mail when log files fail to be archived.

MailConnectionSummary (bool, default 1): True to mail connection summary reports each log rotation interval (if false, then connection summary reports will still be generated and archived, but they will not be mailed). However, this option has no effect if the trace-summary script is not available.

MailFrom (string, default “Big Brother <bro@localhost>”): Originator address for mails. This overrides the Bro script variable Notice::mail_from.

MailHostUpDown (bool, default 1): True to enable sending mail when broctl cron notices the availability of a host in the cluster to have changed.

MailReceivingPackets (bool, default 1): True to enable sending mail when broctl cron notices that an interface is not receiving any packets (note that such mail is not sent when StatsLogEnable is 0).

MailReplyTo (string, default _empty_): Reply-to address for broctl-generated mails.

MailSubjectPrefix (string, default “[Bro]”): General Subject prefix for mails. This overrides the Bro script variable Notice::mail_subject_prefix.

MailTo (string, default “<user>”): Destination address for non-alarm mails. This overrides the Bro script variable Notice::mail_dest.

MakeArchiveName (string, default “${BroBase}/share/broctl/scripts/make-archive-name”): Script to generate filenames for archived log files.

MemLimit (string, default “unlimited”): Maximum amount of memory for Bro processes to use (in KB, or the string ‘unlimited’).

MinDiskSpace (int, default 5): Minimum percentage of disk space available before broctl cron mails a warning. If this value is 0, then no warning will be sent.

PFRINGClusterID (int, default 21): If PF_RING flow-based load balancing is desired, this is where the PF_RING cluster id is defined. In order to use PF_RING, the value of this option must be non-zero.

PFRINGClusterType (string, default “4-tuple”): If PF_RING flow-based load balancing is desired, this is where the PF_RING cluster type is defined. Allowed values are: 2-tuple, 4-tuple, 5-tuple, tcp-5-tuple, 6-tuple, or round-robin. Bro must be linked with PF_RING’s libpcap wrapper and PFRINGClusterID must be non-zero for this option to work.

PFRINGFirstAppInstance (int, default 0): The first application instance for a PF_RING dnacluster interface to use. Broctl will start at this application instance number and increment for each new process running on that DNA cluster. Bro must be linked with PF_RING’s libpcap wrapper, PFRINGClusterID must be non-zero, and you must be using PF_RING+DNA and libzero for this option to work.

Prefixes (string, default “local”): Additional script prefixes for Bro, separated by colons. Use this instead of @prefix.

SaveTraces (bool, default 0): True to let backends capture short-term traces via ‘-w’. These are not archived but might be helpful for debugging.

SendMail (string, default “@SENDMAIL@”): Location of the sendmail binary. Make this string blank to prevent email from being sent. The default value is configuration-dependent and determined automatically by CMake at configure-time. This overrides the Bro script variable Notice::sendmail.

SitePluginPath (string, default _empty_): Directories to search for custom plugins (i.e., plugins that are not included with broctl), separated by colons.

SitePolicyPath (string, default “${PolicyDir}/site”): Directories to search for local (i.e., site-specific) policy files, separated by colons. For each such directory, all files and subdirectories are copied to PolicyDirSiteInstall during broctl ‘install’ or ‘deploy’ (however, if the same file or subdirectory is found in more than one such directory, then only the first one encountered will be used).

SitePolicyScripts (string, default “local.bro”): Space-separated list of local policy files that will be automatically loaded for all Bro instances. Scripts listed here do not need to be explicitly loaded from any other policy scripts.

StatsLogEnable (bool, default 1): True to enable BroControl to write statistics to the stats.log file.

StatsLogExpireInterval (int, default 0): Number of days entries in the stats.log file are kept (zero means never expire).

StatusCmdShowAll (bool, default 0): True to have the status command show all output, or False to show only some of the output (peer information will not be collected or shown, so the command will run faster).

StopTimeout (int, default 60): The number of seconds to wait before sending a SIGKILL to a node which was previously issued the ‘stop’ command but did not terminate gracefully.

StopWait (bool, default 0): True to force the stop command to wait for the post-terminate script to finish, or False to let post-terminate finish in the background.

TimeFmt (string, default “%d %b %H:%M:%S”): Format string to print date/time specifications (see ‘man strftime’).

TimeMachineHost (string, default _empty_): If the manager should connect to a Time Machine, the address of the host it is running on.

TimeMachinePort (string, default “47757/tcp”): If the manager should connect to a Time Machine, the port it is running on (in Bro syntax, e.g., 47757/tcp).

Internal Options ¶

BinDir (string, default “${BroBase}/bin”): Directory for executable files.

Bro (string, default “${BinDir}/bro”): Path to Bro binary.

BroBase (string, default _empty_): Base path of broctl installation on all nodes.

CapstatsPath (string, default “${bindir}/capstats”): Path to capstats binary; empty if not available.

CfgDir (string, default “${BroBase}/etc”): Directory for configuration files.

DebugLog (string, default “${SpoolDir}/debug.log”): Log file for debugging information.

DefaultStoreDir (string, default “${SpoolDir}/stores”): Default directory where Broker data stores will be written if user has not provided further customizations on a per-store basis.

HelperDir (string, default “${BroBase}/share/broctl/scripts/helpers”): Directory for broctl helper scripts.

LibDir (string, default “${BroBase}/lib”): Directory for library files.

LibDirInternal (string, default “${BroBase}/lib/broctl”): Directory for broctl-specific library files.

LocalNetsCfg (string, default “${CfgDir}/networks.cfg”): File defining the local networks.

LockFile (string, default “${SpoolDir}/lock”): Lock file preventing concurrent shell operations.

LogExpireMinutes (int, default 0): Time interval (in minutes) that archived log files are kept (0 means they never expire). Users should never modify this value (see the LogExpireInterval option).

NodeCfg (string, default “${CfgDir}/node.cfg”): Node configuration file.

OS (string, default _empty_): Name of operating system as reported by uname.

PcapBufsize (int, default 128): Number of Mbytes to provide as buffer space when capturing from live interfaces via libpcap.

PcapSnaplen (int, default 9216): Number of bytes per packet to capture from live interfaces via libpcap.

PluginBroDir (string, default “${BroBase}/lib/bro/plugins”): Directory where Bro plugins are located. BroControl will search this directory tree for broctl plugins that are provided by any Bro plugin.

PluginDir (string, default “${LibDirInternal}/plugins”): Directory where standard broctl plugins are located.

PolicyDir (string, default “${BroScriptDir}”): Directory for standard policy files.

PolicyDirSiteInstall (string, default “${SpoolDir}/installed-scripts-do-not-touch/site”): Directory where the shell copies local (i.e., site-specific) policy scripts when installing.

PolicyDirSiteInstallAuto (string, default “${SpoolDir}/installed-scripts-do-not-touch/auto”): Directory where the shell copies auto-generated local policy scripts when installing.

PostProcDir (string, default “${BroBase}/share/broctl/scripts/postprocessors”): Directory for log postprocessors.

ScriptsDir (string, default “${BroBase}/share/broctl/scripts”): Directory for executable scripts shipping as part of broctl.

SpoolDir (string, default “${BroBase}/spool”): Directory for run-time data.

StandAlone (bool, default 0): True if running in stand-alone mode (see elsewhere).

StateFile (string, default “${SpoolDir}/state.db”): File storing the current broctl state.

StaticDir (string, default “${BroBase}/share/broctl”): Directory for static, arch-independent files.

StatsDir (string, default “${LogDir}/stats”): Directory where statistics are kept.

StatsLog (string, default “${SpoolDir}/stats.log”): Log file for statistics.

Time (string, default _empty_): Path to time binary.

TmpDir (string, default “${SpoolDir}/tmp”): Directory for temporary data.

TmpExecDir (string, default “${SpoolDir}/tmp”): Directory where binaries are copied before execution. This option is ignored if HaveNFS is 0.

TraceSummary (string, default “${bindir}/trace-summary”): Path to trace-summary script (empty if not available). Make this string blank to disable the connection summary reports.

Version (string, default _empty_): Version of the broctl.

Plugins ¶

BroControl provides a plugin interface to extend its functionality. A plugin is written in Python and can do any, or all, of the following:

Perform actions before or after any of the standard BroControl commands is executed. When running before the actual command, it can filter which nodes to operate or stop the execution altogether. When running after the command, it gets access to the commands success status on a per-node basis (where applicable).

Add custom commands to BroControl.

Add custom options to BroControl defined in broctl.cfg.

Add custom keys to nodes defined in node.cfg.

A plugin is written by deriving a new class from BroControl class Plugin. The Python script with the new plugin is then copied into a plugin directory searched by BroControl at startup. By default, BroControl searches <prefix>/lib/broctl/plugins; additional directories may be configured by setting the SitePluginPath option. Note that any plugin script must end in *.py to be found. BroControl comes with some example plugins that can be used as a starting point; see the <prefix>/lib/broctl/plugins directory.

In the following, we document the API that is available to plugins. A plugin must be derived from the Plugin class, and can use its methods as well as those of the Node class.

Class `Plugin`¶

class Plugin

The class Plugin is the base class for all BroControl plugins.

The class has a number of methods for plugins to override, and every plugin must at least override name() and pluginVersion().

For each BroControl command foo, there are two methods, cmd_foo_pre and cmd_foo_post, that are called just before the command is executed and just after it has finished, respectively. The arguments these methods receive correspond to their command-line parameters, and are further documented below.

The cmd_<XXX>_pre methods have the ability to prevent the command’s execution, either completely or partially for those commands that take nodes as parameters. In the latter case, the method receives a list of nodes that the command is to be run on, and it can filter that list and returns modified version of nodes to actually use. The standard case would be returning simply the unmodified nodes parameter. To completely block the command’s execution, return an empty list. To just not execute the command for a subset, remove the affected ones. For commands that do not receive nodes as arguments, the return value is interpreted as boolean indicating whether command execution should proceed (True) or not (False).

The cmd_<XXX>_post methods likewise receive the commands arguments as their parameter, as documented below. For commands taking nodes, the list corresponds to those nodes for which the command was actually executed (i.e., after any cmd_<XXX>_pre filtering).

Note that if a plugin prevents a command from executing either completely or partially, it should report its reason via the message() or error() methods.

If multiple plugins hook into the same command, all their cmd_<XXX>_{pre,post} are executed in undefined order. The command is executed on the intersection of all cmd_<XXX>_pre results.

Finally, note that the restart command is just a combination of other commands and thus their callbacks are run in addition to the callbacks for restart.

debug (self, msg)

Logs a debug message in BroControl’s debug log if enabled.

error (self, msg)

Reports an error to the user.

execute (self, node, cmd)

Executes a command on the host for the given node of type Node. Returns a tuple (success, output) in which success is True if the command ran successfully, and output is a string which contains the combined stdout/stderr output.

executeParallel (self, cmds)

Executes a set of commands in parallel on multiple hosts. cmds is a list of tuples (node, cmd), in which the node is a Node instance and cmd is a string with the command to execute for it. The method returns a list of tuples (node, success, output), in which success is True if the command ran successfully, and output is a string containing the combined stdout/stderr output for the corresponding node.

getGlobalOption (self, name)

Returns the value of the global BroControl option name.

See the output of broctl config for a complete list.

getOption (self, name)

Returns the value of one of the plugin’s options, name.

An option has a default value (see options()), which can be overridden by a user in broctl.cfg. An option’s value cannot be changed by the plugin.

getState (self, name)

Returns the current value of one of the plugin’s state variables, name. If it has not yet been set, an empty string will be returned.

Different from options, state variables can be set by the plugin. They are persistent across restarts.

Note that a plugin cannot query any global BroControl state variables.

hosts (self, nodes)

Returns a list of Node objects which is a subset of the list in nodes, such that only one node per host will be chosen. If nodes is empty, then the returned list will be a subset of the entire list of configured nodes.

message (self, msg)

Reports a message to the user.

nodes (self)

Returns a list of all configured Node objects.

parseNodes (self, names)

Returns a tuple which contains two lists. The first list is a list of Node objects for a string of space-separated node names. If a name does not correspond to a known node, then the name is added to the second list in the returned tuple.

setState (self, name, value)

Sets one of the plugin’s state variables, name, to value. The change is permanent and will be recorded to disk.

Note that a plugin cannot change any global BroControl state variables.

broProcessDied (self, node)

Called when BroControl finds the Bro process for Node node to have terminated unexpectedly. This method will be called just before BroControl prepares the node’s “crash report” and before it cleans up the node’s spool directory.

This method can be overridden by derived classes. The default implementation does nothing.

broctl_config (self)

Returns a string containing Bro script code that should be written to the dynamically generated Bro script named “broctl-config.bro”. This provides a way for plugins to easily add Bro script code that depends on broctl settings.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_capstats_post (self, nodes, interval)

Called just after the capstats command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_capstats_pre (self, nodes, interval)

Called just before the capstats command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command. interval is an integer with the measurement interval in seconds.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_check_post (self, results)

Called just after the check command has finished. It receives the list of 2-tuples (node, bool) indicating the nodes the command was executed for, along with their success status.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_check_pre (self, nodes)

Called just before the check command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_cleanup_post (self, nodes, all)

Called just after the cleanup command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_cleanup_pre (self, nodes, all)

Called just before the cleanup command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command. all is boolean indicating whether the --all argument has been given.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_config_post (self)

Called just after the config command has finished.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_config_pre (self)

Called just before the config command is run. Returns a boolean indicating whether or not the command should run.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_cron_post (self, arg, watch)

Called just after the cron command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_cron_pre (self, arg, watch)

Called just before the cron command is run. arg is an empty string if the command is executed without arguments. Otherwise, it is one of the strings: enable, disable, ?. watch is a boolean indicating whether the cron command should restart abnormally terminated Bro processes; it’s only valid if arg is empty.

Returns a boolean indicating whether or not the cron command should run.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_custom (self, cmd, args, cmdout)

Called when a command defined by the commands method is executed. cmd is the command (without the plugin’s prefix), and args is a single string with all arguments. It returns a CmdResult object containing the command results.

If the arguments are actually node names, parseNodes can be used to get the Node objects.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_deploy_post (self)

Called just after the deploy command has finished.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_deploy_pre (self)

Called just before the deploy command is run. Returns a boolean indicating whether or not the command should run.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_df_post (self, nodes)

Called just after the df command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_df_pre (self, nodes)

Called just before the df command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_diag_post (self, nodes)

Called just after the diag command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_diag_pre (self, nodes)

Called just before the diag command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_exec_post (self, cmdline)

Called just after the exec command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_exec_pre (self, cmdline)

Called just before the exec command is run. cmdline is a string with the command line to execute.

Returns a boolean indicating whether or not the exec command should run.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_install_post (self)

Called just after the install command has finished.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_install_pre (self)

Called just before the install command is run. Returns a boolean indicating whether or not the command should run.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_netstats_post (self, nodes)

Called just after the netstats command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_netstats_pre (self, nodes)

Called just before the netstats command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_nodes_post (self)

Called just after the nodes command has finished.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_nodes_pre (self)

Called just before the nodes command is run. Returns a boolean indicating whether or not the command should run.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_peerstatus_post (self, nodes)

Called just after the peerstatus command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_peerstatus_pre (self, nodes)

Called just before the peerstatus command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_print_post (self, nodes, id)

Called just after the print command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_print_pre (self, nodes, id)

Called just before the print command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command. id is a string with the name of the ID to be printed.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_process_post (self, trace, options, scripts, success)

Called just after the process command has finished. Arguments are as with the pre method, plus an additional boolean success indicating whether Bro terminated normally.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_process_pre (self, trace, options, scripts)

Called just before the process command is run. It receives the trace to read from as a string, a list of additional Bro options, and a list of additional Bro scripts.

Returns a boolean indicating whether or not the process command should run.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_restart_post (self, nodes)

Called just after the restart command has finished. It receives a list of nodes indicating the nodes on which the command was executed.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_restart_pre (self, nodes, clean)

Called just before the restart command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command. clean is boolean indicating whether the --clean argument has been given.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_scripts_post (self, nodes, check)

Called just after the scripts command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_scripts_pre (self, nodes, check)

Called just before the scripts command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command. check is boolean indicating whether the -c option was given.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_start_post (self, results)

Called just after the start command has finished. It receives the list of 2-tuples (node, bool) indicating the nodes the command was executed for, along with their success status.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_start_pre (self, nodes)

Called just before the start command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_status_post (self, nodes)

Called just after the status command has finished. Arguments are as with the pre method.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_status_pre (self, nodes)

Called just before the status command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_stop_post (self, results)

Called just after the stop command has finished. It receives the list of 2-tuples (node, bool) indicating the nodes the command was executed for, along with their success status.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_stop_pre (self, nodes)

Called just before the stop command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_top_post (self, nodes)

Called just after the top command has finished. Arguments are as with the pre method. Note that when top is run interactively to auto-refresh continuously, this method will be called once after each update.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_top_pre (self, nodes)

Called just before the top command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command. Note that when top is run interactively to auto-refresh continuously, this method will be called once before each update.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_update_post (self, results)

Called just after the update command has finished. It receives the list of 2-tuples (node, bool) indicating the nodes the command was executed for, along with their success status.

This method can be overridden by derived classes. The default implementation does nothing.

cmd_update_pre (self, nodes)

Called just before the update command is run. It receives the list of nodes, and returns the list of nodes that should proceed with the command.

This method can be overridden by derived classes. The default implementation does nothing.

commands (self)

Returns a set of custom commands provided by the plugin.

The return value is a list of 3-tuples each having the following elements:

command

A string with the command’s name. Note that the command name exposed to the user will be prefixed with the plugin’s prefix as returned by prefix() (e.g., myplugin.mycommand, or just myplugin if the command name is an empty string).

arguments

A string describing the command’s arguments in a textual form suitable for use in the help command summary (e.g., [<nodes>] for a command taking an optional list of nodes). Empty if no arguments are expected.

description

A string with a description of the command’s semantics suitable for use in the help command summary.

This method can be overridden by derived classes. The implementation must not call the parent class’ implementation. The default implementation returns an empty list.

done (self)

Called once just before BroControl terminates. This method can do any cleanup the plugin may require.

This method can be overridden by derived classes. The default implementation does nothing.

hostStatusChanged (self, host, status)

Called when BroControl’s cron command finds the availability of a cluster system to have changed. Initially, all systems are assumed to be up and running. Once BroControl notices that a system isn’t responding (defined as not accepting SSH sessions), it calls this method, passing in a string with the name of the host and a boolean status set to False. Once the host becomes available again, the method will be called again for the same host with status now set to True.

Note that BroControl’s cron tracks a host’s availability across execution, so if the next time it’s run the host is still down, this method will not be called again.

This method can be overridden by derived classes. The default implementation does nothing.

init (self)

Called once just before BroControl starts executing any commands. This method can do any initialization that the plugin may require.

Note that when this method executes, BroControl guarantees that all internals are fully set up (e.g., user-defined options are available). This may not be the case when the class __init__ method runs.

Returns a boolean, indicating whether the plugin should be used. If it returns False, the plugin will be removed and no other methods called.

This method can be overridden by derived classes. The default implementation always returns True.

name (self)

Returns a string with a descriptive name for the plugin (e.g., "TestPlugin"). The name must not contain any whitespace.

This method must be overridden by derived classes. The implementation must not call the parent class’ implementation.

nodeKeys (self)

Returns a list of names of custom keys for nodes (the value of a key can be specified in node.cfg for any node defined there). Node key names are not case-sensitive.

The value for a key will be available from the Node object as attribute <prefix>_<key> (e.g., node.myplugin_mykey). If not set, the attribute will be set to an empty string.

This method can be overridden by derived classes. The implementation must not call the parent class’ implementation. The default implementation returns an empty list.

options (self)

Returns a set of local configuration options provided by the plugin.

The return value is a list of 4-tuples each having the following elements:

name

A string with name of the option (e.g., Path). Option names are not case-sensitive. Note that the option name exposed to the user will be prefixed with your plugin’s prefix as returned by prefix() (e.g., myplugin.Path).

type

A string with type of the option, which must be one of "bool", "string", or "int".

default

The option’s default value. Note that this value must be enclosed in quotes if the type is “string”, and must not be enclosed in quotes if the type is not “string”.

description

A string with a description of the option semantics.

This method can be overridden by derived classes. The implementation must not call the parent class’ implementation. The default implementation returns an empty list.

pluginVersion (self)

Returns an integer with a version number for the plugin. Plugins should increase their version number with any significant change.

This method must be overridden by derived classes. The implementation must not call the parent class’ implementation.

prefix (self)

Returns a string with a prefix for the plugin’s options and commands names (e.g., “myplugin”). The prefix cannot contain any whitespace or dots (because dots are used as separators when forming the plugin’s option names, state variable names, and command names).

Note that BroControl will refuse to load a plugin if its prefix matches the prefix of another loaded plugin (this comparison is not case-sensitive).

This method can be overridden by derived classes. The implementation must not call the parent class’ implementation. The default implementation returns a lower-cased version of name().

Class `Node`¶

class Node

Class representing one node of the BroControl maintained setup. In standalone mode, there’s always exactly one node of type standalone. In a cluster setup, there is zero or one of type logger, exactly one of type manager, one or more of type proxy, and zero or more of type worker. The manager will handle writing logs if there is no logger defined in a cluster.

A Node object has a number of keys with values that are set via the node.cfg file and can be accessed directly (from a plugin) via corresponding Python attributes (e.g., node.name):

name (string)

The name of the node, which corresponds to the [<name>] section in node.cfg.

type (string)

The type of the node. In a standalone configuration, the only allowed type is standalone. In a cluster configuration, the type must be one of: logger, manager, proxy, or worker.

host (string)

The hostname or IP address of the system the node is running on. Every node must specify a host.

interface (string)

The network interface for the Bro worker (or standalone node) to use; empty if not set.

lb_procs (integer)

The number of clustered Bro workers you’d like to start up. If specified, this number must be greater than zero and a load balancing method must also be specified. This option is valid only for worker nodes.

lb_method (string)

The load balancing method to distribute packets to all of the Bro workers. This must be one of: pf_ring, myricom, custom, or interfaces. This option can have a value only if the lb_procs option has a value.

lb_interfaces (string)

A comma-separated list of network interface names for the Bro worker to use. The number of interfaces in this list must equal the value of the lb_procs option.

This option can be specified only when the load balancing method is interfaces.

pin_cpus (string)

A comma-separated list of CPU numbers to which the node’s Bro processes will be pinned. If not specified, then CPU pinning will not be used for this node. This option is supported only on Linux and FreeBSD, and is ignored on all other platforms.

CPU numbering starts at zero (e.g., the only valid CPU numbers for a machine with one dual-core processor would be 0 and 1). If the length of this list does not match the number of Bro processes for this node, then some CPUs could have zero (if too many CPU numbers are specified) or more than one (if not enough CPU numbers are specified) Bro processes pinned to them. Only the specified CPU numbers will be used, regardless of whether additional CPU cores exist.

env_vars (string)

A comma-separated list of environment variables to set when running Bro (e.g., env_vars=VAR1=1,VAR2=2). These node-specific values override any global values specified in the broctl.cfg file.

aux_scripts (string)

Any node-specific Bro script configured for this node.

zone_id (string)

If BroControl is managing a cluster comprised of nodes using non-global IPv6 addresses, then this configures the RFC 4007 zone_id string that the node associates with the common zone that all cluster nodes are a part of. This identifier may differ between nodes.

Any attribute that is not defined in node.cfg will be empty.

In addition, plugins can override Plugin.nodeKeys to define their own node keys, which can then be likewise set in node.cfg. The key names will be prepended with the plugin’s Plugin.prefix (e.g., for the plugin test, the node key foo is set by adding test.foo=value to node.cfg).

Finally, a Node object has the following methods that can be called from a plugin:

cwd (self)

Returns a string with the node’s working directory.

describe (self)

Returns an extended string representation of the node including all its keys with values (sorted by key).

getPID (self)

Returns the process ID of the node’s Bro process if running, and None otherwise.

getPort (self)

Returns an integer with the port number that this node’s communication system is listening on for incoming connections, or -1 if no such port has been set yet.

hasCrashed (self)

Returns True if the node’s Bro process has exited abnormally.

Questions and Answers ¶

Can I use an NFS-mounted partition as the cluster’s base directory to avoid the ``rsync``’ing?: Yes. BroBase can be on an NFS partition. Configure and install the shell as usual with --prefix=<BroBase>. Then add HaveNFS=1 and SpoolDir=<spath> to broctl.cfg, where <spath> is a path on the local disks of the nodes; <spath> will be used for all non-shared data (make sure that the parent directory exists and is writable on all nodes!). Then run make install again. Finally, you can remove <BroBase>/spool (or link it to <spath>). In addition, you might want to keep the log files locally on the nodes as well by setting LogDir to a non-NFS directory. (Only the manager’s logs will be kept permanently, the logs of workers/proxies are discarded upon rotation.)
What do I need to do when something in the Bro distribution changes?: After pulling from the main Bro git repository, just re-run make install inside your build directory. It will reinstall all the files from the distribution that are not up-to-date. Then do broctl deploy to make sure everything gets pushed out.
Can I change the naming scheme that BroControl uses for archived log files?: Yes, set MakeArchiveName to a script that outputs the desired destination file name for an archived log file. The default script for that task is <BroBase>/share/broctl/scripts/make-archive-name, which you can use as a template for creating your own version. See the beginning of that script for instructions.
Can BroControl manage a cluster of nodes over non-global IPv6 scope (e.g. link-local)?: This used to be supported through a ZoneID option in broctl.cfg, but no longer works in later versions of Bro which use Broker as the communication framework. Please file a feature request if this is important to you.