Commander

Commander is two things:

1. A deployment library modeled after fabric
2. A remote command runner

Improvements over fabric

• Ability to run commands in parallel (added in Fabric 1.3.0 on 2011-10-24)
• Tasks simpler to call can be called as functions from python (see Fabric library use)
• Avoids using a global state to allow for easier parallelism
• Switchable ssh backend (in progress)

Why fabric is better

• Larger community
• More mature
• More features

Deployment Libary

A simple deployment example <example.py>

from commander.deploy import hosts

@hosts(["host1", "host2", "host3"])
def hostname(ctx):
    ctx.remote("hostname")

And then from the commandline

# commander -l example.py 
Available commands:

    hostname

# commander example.py hostname
Running 'hostname'
[host1] run: hostname
[host1] out: host1
[host2] run: hostname
[host2] out: host2
[host3] run: hostname
[host3] out: host3

Your deployment definitions can also be called directly from another python script <example2.py>

from example import hostname
hostname()

And then

# python2.6 example2.py
[host1] run: hostname
[host1] out: host1
[host2] run: hostname
[host2] out: host2
[host3] run: hostname
[host3] out: host3

Remote Command Runner

After defining a dictionary of hosts in /etc/commanderconfig.py e.g.,

hostgroups = {
    'hostgroup1': ['host1', 'host2', 'host3'],
}

From the commandline

# issue-multi-command hostgroup1 hostname
[host1] run: hostname
[host1] out: host1
[host2] run: hostname
[host2] out: host2
[host3] run: hostname
[host3] out: host3