exabgp1

Usage

Overview

exabgp allows engineers to control their network from commodity servers. Possible uses include DDoS mitigation, network visualisation, service high availability and implementing anycast. exabgp does not perform any FIB manipulation on the system it runs on; if you need that this is not the program for you. exabgp can also print received BGP messages into readable plain text or JSON formatted text.

The arguments are as follows:

--help | -h

Display summary of usage and configuration of exabgp.

--version | -v

Display the exabgp version number and exit.

--root folder | -f folder

Root folder where etc, bin, sbin are located.

--env env-config | -e env-config

Specify where the environment configuration file can be found.

--full-ini | --fi

Display the full environment configuration using on stdout using the ini format.

--diff-ini | --di

Display the non-default environment configuration on stdout using the ini format.

--full-env | --fe

Display the full environment configuration on stdout using the env format.

--diff-env | --de

Display the non-default configuration on stdout using the env format.

--run helper

Do not run ExaBGP but one of its helper programs, options are: healthcheck and cli

--debug | -d

Start the python debugger on serious logging on and on reception of the SIGTERM signal. This is a shortcut for exabgp.log.all=true and exabgp.log.level=DEBUG.

--validate

Validate the configuration file format only.

--signal time

Issue a SIGUSR1 signal to reload the configuration after the specified number of seconds, only useful for code debugging.

--once | -1

Only perform one attempt to connect to peers, used mostly for debugging.

--pdb | -p

Start the python debugger on critical logging, reception of SIGTERM, and on uncaught python exceptions. This is a shortcut for exabgp.pdb.enable=true.

--memory | -s

Display memory usage information on program exit.

--profile profile

Enable collection of profiling information to the given file. This is a shortcut for exabgp.profile.enable=true and exabgp.profile.file=profile.

--test | -t

Only do a configuration validity check.

--decode hex-message | -x hex-message

Decode a raw route packet in hexadecimal string.

Environment

The configuration of exabgp is split in two:

• The environment configuration which controls the basic execution of exabgp such as logging, daemonizing, pid-file, profiling etc.

• The BGP configuration of exabgp, which specifies which neighbors it should talk BGP with and all other aspects of the BGP configuration.

The environment configuration can be specified a number of different ways, with different priority:

1. Command line values using dot-separated notation.

2. Environment variables using dot-separated notation.

3. Command line values using underscore-separated notation.

4. Environment variables using underscore-seprated notation.

5. The values from the ini configuration file, /etc/exabgp/exabgp.env

6. The built-in default values.

The following environment variables can be used to configure the basic execution of exabgp:

exabgp.api.encoder

(experimental) default encoder to use with external API (text or json). Default: text.

exabgp.api.highres

Controls whether to use high-resolution timestamps in JSON. Default: false.

exabgp.api.respawn

Controls whether to respawn a helper process if it dies. Default: false.

exabgp.bgp.openwait

Controls how many seconds we should wait for a BGP open message once the TCP session is established. Default: 60 seconds.

exabgp.cache.attributes

Controls whether all attributes (configuration and wire) should be cached for faster parsing. Default: true.

exabgp.cache.nexthops

(deprecated) Controls whether route next-hops are cached. Default: true.

exabgp.daemon.daemonize

Controls whether exabgp should run in the background. Default: false.

exabgp.daemon.pid

Where to save the PID of exabgp if we manage it. Default: '' (not set).

exabgp.daemon.user

The user to run exabgp as. Should be an unprivileged user. Default: nobody.

exabgp.log.all

Controls whether debug logging should be done for everything. Default: false.

exabgp.log.configuration

Controls whether logging should be done for the configuration and command parsing. Default: true.

exabgp.log.daemon

Controls whether logging should be done for PID change, forking, etc. Default: true.

exabgp.log.destination

Controls where logging should be sent. syslog (or no setting) sends the data to the local syslog server. host:<location> sends the data to a remote syslog server. stdout sends the data to stdout. stderr sends the data to stderr. <filename> sends the data to the named file. Default: stdout.

exabgp.log.enable

Controls whether logging should be done. Default: true.

exabgp.log.level

Sets the minimum severity level to log. Default: INFO.

exabgp.log.message

Controls logging of changes in route announcement in config reload. Default: false.

exabgp.log.network

Controls logging of networking information (TCP/IP state, network state etc.). Default: true.

exabgp.log.packets

Controls logging of BGP packets sent and received. Default: false.

exabgp.log.parser

Controls logging of BGP message parsing details. Default: false.

exabgp.log.processes

Controls logging of forked processes. Default: true.

exabgp.log.reactor

Controls logging of signals received and command reload. Default: true.

exabgp.log.rib

Controls logging of changes in locally configured routes. Default: false.

exabgp.log.routes

Controls logging of received routes. Default: false.

exabgp.log.short

Coontrols whether to use long or short log format (not prepended with time, level, pid and source). Default: false.

exabgp.log.timers

Controls logging of keepalive timers. Default: false.

exabgp.pdb.enable

Controls whether pdb, the python interactive debugger should be started on program faults. Default: false.

exabgp.profile.enable

Controls whether profiling of the code should be done. Default: false.

exabgp.profile.file

Controls where profiling results should be written. None/empty means stdout. Default: empty.

exabgp.reactor.speed

Controls the time of one reactor loop. Use only if you understand the code. Default: 1.0.

exabgp.tcp.acl

(experimental, unimplemented). Default: empty.

exabgp.tcp.bind

IP address to bind to when listening (no ip to disable). Default: empty.

exabgp.tcp.delay

Start to announce routes when the minutes in the hour is a modulo of this number. Default: 0.

exabgp.tcp.once

Only perform one TCP connection attempt per peer, for debugging scripts. Default: false.

exabgp.tcp.port

Port to bind to when listening. Default: 179.

Files

/etc/exabgp/exabgp.env is the default file for setting the "environment" variables controlling the execution of exabgp. An alaternative "env" configuration file can be supplied via the --env env-config argument. The format of this file is "Windows INI format". All the default settings can be shown with the exabgp --test --full-init command, an example showing parts of this output is:

[exabgp.api]
encoder = text
highres = false
respawn = false
[exabgp.bgp]
openwait = 60

Additionally, the user will need to supply a configuration file controlling the BGP configuration of exabgp, in the format described in exabgp.conf(5).

Signals

exabgp catches a few different signals to control specific actions. They are:

ALRM

Restarts exabgp.

USR1

Causes exabgp to reload the configuration.

USR2

Causes exabgp to reload the configuration and restart any forked processes.

TERM

Terminates exabgp.

HUP

Also terminates exabgp (does not reload the configuration anymore).

Reloading large configurations using signals is currently not recommended, because the configuration parsing code is currently blocking. Therefore if you have a large configuration change, it could cause the peer to miss some keepalive and cause a session flap.

Diagnostics

The --test argument is useful to validate the syntax of the configuration file. The --debug flag will provide copious debug output to whereever the various exabgp.log variable settings dictate.