Reliable way to determine if a process on a remote host is running or not using Python and Fabric. Tested on CentOs 5.10 and Ubuntu 12.04

fab_utils.py

# NOTE: the hide('warnings', 'running', 'stdout', 'stderr') quiets the
# dumping of the commands fabric runs and its responses, which I find
# rather annoying.

def is_running(pidfile, pidpath):
    with cd(pidpath):
        if exists(pidfile):
            with settings(hide('warnings', 'running', 'stdout', 'stderr'), warn_only=True):
                return run('ps -p $(cat %s) --no-header' % pidfile).succeeded
        else:
            # assume it isn't running if no pidfile is available
            return False