Paul,
Thanks very much for yor explanation - that's cleared things up and also
accounted for why some things had not been running as expected
Cheers
Paul
2008/12/10 Paul Lathrop <[EMAIL PROTECTED]>
>
> Paul,
>
> 'subscribe' and 'notify' are supersets of 'require' and 'before,'
> respectively. While 'require' and 'before' simply insist that the
> resource ordering occurs in a certain fashion, 'subscribe' and
> 'notify' make use of "events". An "event" occurs whenever a resource
> changes, and some resources behave differently when they receive an
> "event". For example, say you have the following:
>
> file { "/etc/apache/apache.conf":
> source => "puppet:///apache/apache.conf",
> before => Service["apache"];
> }
>
> service { "apache":
> enable => true,
> ensure => running;
> }
>
> When you run puppet on a new machine, it will copy the apache.conf
> from the puppetmaster first, then enable and start apache. When the
> file changes, the puppetmaster will fetch the new file, but *nothing
> will happen to apache*. This is the use case for subscribe/notify:
>
> file { "/etc/apache/apache.conf":
> source => "puppet:///apache/apache.conf",
> notify => Service["apache"];
> }
>
> service { "apache":
> enable => true,
> ensure => running;
> }
>
> With this manifest, puppet will notice that the file has changed, and
> will generate an "event" which it will send to the "apache" service.
> Service resources are restarted when they receive events.
>
> Note that 'subscribe' is a superset of 'require' so the resources will
> still be applied in the correct order.
>
> Does this make more sense now?
>
> --Paul
>
> On Wed, Dec 10, 2008 at 2:12 PM, paul matthews
> <[EMAIL PROTECTED]> wrote:
> > Like Matt I have been using "before=>" statements as opposed to
> "notify=>"
> > to try and ensure dependency order. Could someone highlight the
> distinction
> > as both seem to ensure a task is run and completed before the next step
> is
> > called.
> >
> > Thanks
> > Paul
> >
> > 2008/12/10 Paul Lathrop <[EMAIL PROTECTED]>
> >>
> >> Mat,
> >>
> >> This should work (untested):
> >>
> >> file { "/tmp/server_binary":
> >> source => "puppet:///files/server_binary",
> >> notify => Exec["stop-server"];
> >> }
> >>
> >> file { "/usr/local/sbin/server_binary":
> >> source => "/tmp/server_binary",
> >> require => Exec["stop-server"],
> >> notify => Exec["start-server"]
> >> }
> >>
> >> # Stops the server
> >> exec { "/usr/local/sbin/stop-server":
> >> alias => "stop-server",
> >> refreshonly => true
> >> }
> >>
> >> # Starts the server
> >> exec { "/usr/local/sbin/start-server":
> >> alias => "start-server",
> >> refreshonly => true
> >> }
> >>
> >> --Paul
> >>
> >> On Tue, Dec 9, 2008 at 1:09 PM, Mathew Binkley <[EMAIL PROTECTED]
> >
> >> wrote:
> >> >
> >> > Hi. I'm hoping that someone can help me with a simple example. We
> are
> >> > trying to use puppet to update a server binary to a group of machines.
> >> > Here's pseudocode for what I'm trying:
> >> >
> >> > if (server_binary has changed) {
> >> > 1) stop the old server
> >> > 2) overwrite the old server binary by
> >> > fetching the new server binary from puppet
> >> > 3) start the new server
> >> > }
> >> >
> >> > Here's the puppet manifest I wrote to handle this, but it isn't
> working
> >> > properly. It is not working as intended, and is 1) downloading the
> new
> >> > binary and then 2) stopping the server, which screws up our data.
> I've
> >> > been looking through the documentation, and it isn't clear which
> >> > permutation of before, require, subscribe, or notify is necessary to
> >> > accomplish this. Hope someone can enlighten me. - Mat
> >> >
> >> >
> >> > file { "/usr/local/sbin/server_binary":
> >> > source => "puppet:///files/server_binary",
> >> > require => Exec["stop-server"],
> >> > before => Exec["start-server"]
> >> > }
> >> >
> >> > # Stops the server
> >> > exec { "/usr/local/sbin/stop-server":
> >> > alias => "stop-server",
> >> > refreshonly => true
> >> > }
> >> >
> >> > # Starts the server
> >> > exec { "/usr/local/sbin/start-server":
> >> > alias => "start-server",
> >> > refreshonly => true
> >> > }
> >> >
> >> > >
> >> >
> >>
> >>
> >
> >
> > >
> >
>
> >
>
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