[Pacemaker] ifstatus OCF RA

[Dejan Muhamedagic]

Hi,

On Tue, Feb 22, 2011 at 08:54:14AM +0100, Florian Haas wrote:
> On 2011-02-22 00:19, Frederik Schüler wrote:
> > Hi,
> > 
> > On Monday 21 February 2011 21:29:19 Florian Haas wrote:
> >>> as the various ocf:*:ping[d] incarnations don't meet my specific needs,
> >>
> >> May I ask why and how?
> > 
> > ocf:pacemaker:ping works, but takes approx. 25-30s to react at all, and 
> > approx. 40s to complete the failover. But I need an immediate failover, 
> > exactly as it worked ages ago with heartbeat-2 and ipfail.
> 
> Well how about pushing down your monitor interval to something like 5
> seconds, set attempts to 1, set timeout to 1, and dampen to 0? Then
> basically as soon as you lose one ping, you can fail over.
> 
> >> Well, what if the link is up but there's an upstream problem?
> > 
> > Good point, but this requirement is customer-driven. I have the cluster to 
> > initiate a failover as quickly as possible within the test cases.
> 
> This sounds like a good time to educate the customer that too short
> failover times are more of a curse rather than a blessing. :)

Right. But sometimes people need to learn the hard way.

> > I have a working setup with ocf:pacemaker:ping, but this was rejected as being 
> > "too slow".
> > 
> >> I've
> >> always liked how ocf:pacemaker:ping actually monitors connectivity to an
> >> upstream IP, which covers both immediate link failure and upstream
> >> problems. Similar to how in active/backup bonding, you can fail over
> >> based on the status of an ARP request, rather than MII link status.
> > 
> > I just checked the redhat cluster suite: the ip.sh RA there has a monitor_link 
> > option, which does exactly what my ifstatus RA does. 
> > Maybe this functionality could be added to the IPaddr2 script, but I guess 
> > that wouldn't have more chances of being added than this one, correct?
> 
> Improving an existing resource agent pretty much always stands better
> chances of being merged than adding a new one. That's my opinion, surely
> others will correct me if theirs differ.

I also think that this would fit better into the existing IPaddr2
RA. After all, it is about the network interface.

Somebody recently posted a set of monitor improvements for
IPaddr2. Lars (Ellenberg) was on that. The link check should be
coordinated with that set of patches, so that we end up with a
consolidated user interface.

Cheers,

Dejan

> Cheers,
> Florian
> 



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