How to use a custom status command for a service in puppet?

Question

I am using debian squeeze with PostgreSQL 9.1 from backports. Puppet has version 2.7.14. Unfortunatly the init script returns the wrong exit code for status. Therefore I wrote a custom status command to detect whether postgresql is running or not.

service { 'postgresql':
  ensure => running,
  enable => true,
  hasstatus  => false,
  hasrestart => true,
  status => "pg_lsclusters -h | awk 'BEGIN {rc=0} {if ($4 != \"online\") rc=3} END { exit rc }'",
  provider => debian,
}

My command works like a charme, but puppet seems to have a problem. I always get notice: /Stage[main]/Postgresql/Service[postgresql]/ensure: ensure changed 'stopped' to 'running' although it is already running.

So tried the following:

service { 'postgresql':
  ensure => running,
  enable => true,
  hasstatus  => false,
  hasrestart => true,
  status => "exit 0",
  provider => debian,
}

As I understood this custom status command, puppet should always think that postgresql is running. Nevertheless puppet tries to start postgresql - every time.

What is my fault? Or is it a bug in puppet?

Solution

My best guesses are that the $4 in your command is getting swallowed up by puppet's own interpolation and that exit 0 doesn't quite work right due to shell interaction issues.

I would try a few things.

1. If the problem is puppet's interpolation on $4 in your command escape the $ like so: status => "pg_lsclusters -h | awk 'BEGIN {rc=0} {if (\$4 != \"online\") rc=3} END { exit rc }'" (sometimes more backslashes are required, but I'm pretty sure 1 is enough here).
2. Make sure the test command is really working right. exit is a shell internal and I'm not sure how puppet will treat that. So use the canonical "return success" command instead: status => "/bin/true"

3. Maybe status is being overridden by provider => debian (which would be a puppet bug), so instead specify all the commands and use the base provider (this won't enable properly, however):

   service { 'postgresql':
     provider => base,
     ensure   => 'running',
     start    => '/etc/init.d/postgresql start',
     restart  => '/etc/init.d/postgresql restart',
     stop     => '/etc/init.d/postgresql stop',
     status   => "pg_lsclusters -h | awk 'BEGIN {rc=0} {if (\$4 != \"online\") rc=3} END { exit rc }'",
   }
   

Comments

[Admin]

Your manifest looks correct, so this sounds like a bug in Puppet. It's a long shot, but try setting provider => init (and remove the enable parameter).

[Admin]

@Zoredache you are right. With sh -c 'exit 0' the status command of puppet works as expected!

[ravi yarlagadda]

One other thing: similar to the exec type, I think puppet needs full paths to executables. Try setting those to the full path in your status line, if you haven't set one globally?

[cpl593x]

@ShaneMadden: Puppet doesn't necessarily need full paths to commands, though assuming it needs them doesn't hurt anything. In addition to a some sort of default path (PATH in environment daemon was started in?) exec accepts a path param and you can set a default path with Exec { path => '/usr/bin:/bin' } or Exec { path => ['/usr/bin'],['/bin']}. There's a similar 'path' on Service, but it appears to be primarily used with certain providers for finding init scripts, rather than as a normal shell-style command search path.

[MMore]

Thanks! The interpolation of $4 was the problem. I replaced it with \$4 and now everything works as expected :)