[Pacemaker] custom resource-agent

[Dejan Muhamedagic]

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?

Thanks,

Dejan

> During this migration time there's the possibility that trying to
> use the address will trigger problems (but enabling it early and
> listening shouldn't be a problem)
> 
> David Lang
> 
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