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128 lines
3.6 KiB
ReStructuredText
128 lines
3.6 KiB
ReStructuredText
.. _command-scripting:
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Command Scripting
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=================
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VyOS supports executing configuration and operational commands non-interactively
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from shell scripts.
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To include VyOS specific functions and aliases you need to ``source
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/opt/vyatta/etc/functions/script-template`` files at the top of your script.
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.. code-block:: none
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#!/bin/vbash
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source /opt/vyatta/etc/functions/script-template
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exit
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Run configuration commands
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--------------------------
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Configuration commands are executed just like from a normal config session. For
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example, if you want to disable a BGP peer on VRRP transition to backup:
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.. code-block:: none
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#!/bin/vbash
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source /opt/vyatta/etc/functions/script-template
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configure
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set protocols bgp 65536 neighbor 192.168.2.1 shutdown
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commit
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exit
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Run operational commands
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------------------------
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Unlike a normal configuration sessions, all operational commands must be
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prepended with ``run``, even if you haven't created a session with configure.
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.. code-block:: none
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#!/bin/vbash
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source /opt/vyatta/etc/functions/script-template
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run show interfaces
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exit
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Other script language
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---------------------
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If you want to script the configs in a language other than bash you can have
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your script output commands and then source them in a bash script.
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Here is a simple example:
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.. code-block:: python
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#!/usr/bin/env python
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print "delete firewall group address-group somehosts"
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print "set firewall group address-group somehosts address '192.0.2.3'"
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print "set firewall group address-group somehosts address '203.0.113.55'"
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.. code-block:: none
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#!/bin/vbash
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source /opt/vyatta/etc/functions/script-template
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configure
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source < /config/scripts/setfirewallgroup.py
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commit
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Executing Configuration Scripts
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-------------------------------
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There is a pitfall when working with configuration scripts. It is tempting to
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call configuration scripts with "sudo" (i.e., temporary root permissions),
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because that's the common way on most Linux platforms to call system commands.
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On VyOS this will cause the following problem: After modifying the configuration
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via script like this once, it is not possible to manually modify the config
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anymore:
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.. code-block:: none
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sudo ./myscript.sh # Modifies config
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configure
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set ... # Any configuration parameter
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This will result in the following error message: ``Set failed`` If this happens,
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a reboot is required to be able to edit the config manually again.
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To avoid these problems, the proper way is to call a script with the
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``vyattacfg`` group, e.g., by using the ``sg`` (switch group) command:
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.. code-block:: none
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sg vyattacfg -c ./myscript.sh
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To make sure that a script is not accidentally called without the ``vyattacfg``
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group, the script can be safeguarded like this:
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.. code-block:: none
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if [ "$(id -g -n)" != 'vyattacfg' ] ; then
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exec sg vyattacfg -c "/bin/vbash $(readlink -f $0) $@"
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fi
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Postconfig on boot
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------------------
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The ``/config/scripts/vyos-postconfig-bootup.script`` script is called on boot
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after the VyOS configuration is fully applied.
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Any modifications done to work around unfixed bugs and implement enhancements
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which are not complete in the VyOS system can be placed here.
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The default file looks like this:
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.. code-block:: none
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#!/bin/sh
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# This script is executed at boot time after VyOS configuration is fully
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# applied. Any modifications required to work around unfixed bugs or use
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# services not available through the VyOS CLI system can be placed here.
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.. hint:: For configuration/upgrade management issues, modification of this
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script should be the last option. Always try to find solutions based on CLI
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commands first.
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