[Pacemaker] ifstatus OCF RA
Dejan Muhamedagic
dejanmm at fastmail.fm
Tue Feb 22 08:30:00 UTC 2011
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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