[chef] Re: Re: setting node attr if certain process is running

ruby_block! That's right, I knew execute didn't feel right.

I'll give your advice a try. Thanks Daniel.

kallen


On Tue, 03 Sep 2013, Daniel DeLeo wrote:

>
>
> On Tuesday, September 3, 2013 at 2:42 PM, 
> 
 
>  wrote:
>
> >
> > Hiya,
> >
> > I'm creating an internal CI service for my group, and there's this bit I'm
> > trying to implement, but it's not working yet. I'm hoping someone could 
> > provide
> > tips. It is possible I'm going about this in an anti-pattern way. Feedback
> > appreciated:
> >
> > When a "worker" node is launched (ec2), a master CI node waits for the 
> > worker
> > node to finish running chef and become ready to take commands from the 
> > master CI
> > node. My idea is, the master CI node polls the chef API looking for a 
> > certain
> > node attribute of this particular worker node.
> >
> > On the worker node, in the first chef run, I want to have it set for 
> > itself an
> > attribute that indicates it's "ready". If it's not ready, it's "pending". 
> > For
> > now, let's just say node's readiness is satisfied if mysql is running. If 
> > it's
> > running, the node should set this attr within the recipe:
> >
> > node.set['macabre']['salad']['bacon']['state'] = "ready"
> >
> > But I'm failing at getting the node to set this correctly.
> >
> > This code below was my first try, but it doesn't work at all in that it 
> > falsely
> > sets "ready" every chef run, regardless if mysql is running or not. 
> > Should this
> > work the way I've written it?
> >
> > # This is falsely setting "ready" every time
> > if `/sbin/pidof mysql >/dev/null 2>&1`
> >
> >
>
> This returns a string which is a "truthy" value in ruby. You can use 
> system("command") instead.
>
> > Chef::Log.debug("HIGGS-BOSON: setting bacon state ready")
> > node.set['macabre']['salad']['bacon']['state'] = "ready"
> > else
> > Chef::Log.debug("HIGGS-BOSON: setting bacon state pending")
> > node.set['macabre']['salad']['bacon']['state'] = "pending"
> > end
> >
> >
> > And here's my second try. It's failing in that it takes 2 chef client 
> > runs to
> > actually get the correct state reported: if current node attr state is 
> > "ready",
> > I stop mysql, then run chef again, the state gets set to "ready" again. 
> > But upon
> > a second chef run, with mysql still stopped, the state correctly gets set 
> > to
> > "pending". When I see this kind of thing happening, it tells me I need to 
> > think
> > about the chef client run in compile time vs run time. I tried the 
> > following,
> > but it takes 2 chef client runs to see the correct state:
> >
> > e = execute "is mysql running" do
> > action :nothing
> > command "sleep 0"
> > user "root"
> > pidfile="/var/lib/mysql/#{node['fqdn']}.pid"
> > if File.exists?("#{pidfile}")
> > Chef::Log.debug("HIGGS-BOSON: setting bacon state ready. pidfile: 
> > #{pidfile}")
> > node.set['macabre']['salad']['bacon']['state'] = "ready"
> > else
> > Chef::Log.debug("HIGGS-BOSON: setting bacon state pending")
> > node.set['macabre']['salad']['bacon']['state'] = "pending"
> > end
> >
> > end
> >
> > e.run_action(:run)
> You probably want a ruby_block resource here. The part of a resource 
> declaration inside the `do???end` is evaluated immediately at compile time.
>
> >
> >
> > So, yeah. Any advice?
> >
> > TIA,
> > kallen
> >
> >
>
> HTH,
>
> --
> Daniel DeLeo
>
>