GOV.UK Fabric Scripts

Fabric is a command-line tool for application deployment and systems administration tasks. It allows the user to run commands across a server farm.

This repository is intended to be setup and run on your local workstation/laptop.

Setup

To install the dependencies:

$ pip install -Ur requirements.txt

NB: if you get a "pip: command not found" error, run this first:

$ sudo easy_install pip

Configure it (see the fabric documentation for more examples),

$ echo 'user = jimbob' >> ~/.fabricrc

Commands

You can view a list of the available tasks:

$ fab -l

And execute against an environment and set of hosts like so:

$ fab preview all hosts
...
$ fab preview class:frontend do:'uname -a'
...

Targeting groups of machines

Fabric tasks can be run on groups of machines in a variety of different ways.

By Puppet class:

# target all machines that have the 'govuk::safe_to_reboot::yes' class
$ fab preview puppet_class:govuk::safe_to_reboot::yes do:'uname -a'

By numeric machine suffix:

# target all machines that end in '2'
$ fab preview numbered:2 do:'uname -a'

By node type (as defined in Puppet):

# target all 'frontend' machines
$ fab preview node_type:frontend do:'uname -a'

By the node name:

# target just one node
$ fab production -H backend-3.backend do:'uname -a'

Syncing postgres machines

An example

fab <env> -H '<src_db>' postgresql.sync:<db_name>,<dst_db> -A

the -A must be specified to forward the agent

This will sync the specified database <db_name> from the machine with the hostname of <src_db> to the machine with hostaname <dst_db>. It will destroy data on the destination db