Fabric

​fabric is a python framework for executing commands either locally or on a series of remote hosts.

Our puppet repo contains a fabric directory with a fabfile.py the defines commands to help with the management of our servers.

Why do we need fabric if we have puppet?

Puppet allows us to easily ensure that a set of commands and files are executed and copied to our servers (and will execute/copy the commands/files over and over again if necessary).

fabric allows us to execute/copy a command/file to one or more servers once and witness the output. Also, fabric allows us to perform operations locally, like list available servers or automate setting up a git remote for each server's puppet repository.

How do I install fabric?

apt-get install fabric

I've written our fabfile.py using fabric 0.9.1.

How do I use our fabric commands?

First, cd into the fabric directory. All fabric commands must be executed from the fabric directory.

Next, run the fab command followed by one or more sub-commands.

For example:

fab listServers

Will generate a list of servers located in our manifests/nodes/production directory.

You can limit the list by adding a colon separted argument to the command, by either specifying a specific server:

0 jamie@chicken:fabric$ fab listServers:mandela
mandela

Done.
0 jamie@chicken:fabric$

Or, by specifying a phrase to grep all server manifests for:

0 jamie@chicken:fabric$ fab listServers:mosh
albizu
chavez
daza
debs
didier
eagle
ella
jones
julia
june
lucius
lucy
lumumba
malcolm
mandela
menchu
proudhon
rodolpho
roe
sojourner
viewsic

Done.
0 jamie@chicken:fabric$

listServers is a local command, meaning it is executed on your computer.

In addition, there are several available remote commands, which will execute on remote servers. When running a remote command, the hosts you want to execute on much be specified with the h command, using the same syntax as listServers. For example, the true command is a test command that simply executes /usr/bin/true on the remote server:

0 jamie@chicken:fabric$ fab h:mandela true
[root@mandela.mayfirst.org] run: true

Done.
Disconnecting from root@mandela.mayfirst.org... done.
0 jamie@chicken:fabric$

What other commands are available?

Run:

fab -l

To see a list of all available commands.

How can I add new commands?

Simply edit the fabfile.py and commit and push your changes.