[Pacemaker] custom resource-agent

[Dejan Muhamedagic]

On Tue, Oct 01, 2013 at 10:07:12AM -0700, David Lang wrote:
> On Tue, 1 Oct 2013, Dejan Muhamedagic wrote:
> 
> >On Tue, Oct 01, 2013 at 07:22:20AM -0700, David Lang wrote:
> >>On Tue, 1 Oct 2013, Dejan Muhamedagic wrote:
> >>
> >>>Hi David,
> >>>
> >>>On Mon, Sep 30, 2013 at 12:41:23PM -0700, David Lang wrote:
> >>>>On Mon, 30 Sep 2013, David Lang wrote:
> >>>>
> >>>>>On Mon, 30 Sep 2013, Michael Schwartzkopff wrote:
> >>>>>
> >>>>>>Am Montag, 30. September 2013, 21:12:56 schrieb Peter Romfeld:
> >>>>>>>I am working in AWS i cant just use a VIP i need to use a floating
> >>>>>>>secondary IP which i reassign through script, i want to let pacemaker
> >>>>>>>handle the reassignment...
> >>>>>>
> >>>>>>Please explain the difference of a VIP and a "secondary IP" in
> >>>>>>your opinion.
> >>>>>
> >>>>>with AWS you need to inform amazon of the change, not just change
> >>>>>the IP on the local box, that requires much more work than a
> >>>>>simple local VIP
> >>>>
> >>>>being more detailed, instead of just
> >>>>ifconfig eth0:0 $vip
> >>>>you have to do something like
> >>>>
> >>>>/opt/aws/bin/ec2-assign-private-ip-addresses -n $ENI_ID --secondary-private-ip-address $VIP --allow-reassignment --region $REGION
> >>>
> >>>We may consider adding such an option to IPaddr2. Has anybody
> >>>ever tried that?
> >>>
> >>>>pingresult=`ping -c 1 -W 1 $VIP | grep time= | wc -l`
> >>>>if [ "$pingresult" == "0" ]; then
> >>>> echo `date` "-- Restarting network"
> >>>> /sbin/service network restart > /dev/null 2>&1
> >>>
> >>>That may break the cluster communication, which may lead to split
> >>>brain, etc. Is that really the only way?
> >>
> >>It's not the only way, but you do have the problem that the call to
> >>aws management interface is asynchronous, you don't know when it's
> >>going to complete, and until it does, the IP doesn't actually work.
> >
> >Wouldn't it be then safer to wait until it starts working, i.e.
> >to monitor in a loop?
> 
> that's exactly what the snippet of code above is for, to detect when
> the other box no longer has the address.

Hmm, perhaps I'm missing something, but I couldn't notice a loop
in that code. What I meant was something like this:

while ! ping -c 1 -W 1 $VIP | grep -qs time=; do
	:
done

Then network restart wouldn't be necessary, right? Sorry, I don't
know much about aws.

Cheers,

Dejan

> David Lang
> 
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