[Pacemaker] Antwort: IPaddr2 resource IP unavailable on 'lo' interface for brief period after start

[alexander.krauth at basf.com]

"Patrick H." <pacemaker at feystorm.net> schrieb am 27.08.2011 10:22:08:
> [Pacemaker] IPaddr2 resource IP unavailable on 'lo' interface for brief 
period after start
> 
> So the issue is that whenever I start up an IP with an IPaddr2 resource, 
the IP is unavailable when attempting to connect via lo interface for 
approximately 21 seconds after the resource is started.
> 
> What I am doing is starting up the IP resource, and then I have another 
resource that tries to start, but prior to starting it does a status check 
by connecting to that IP on a TCP port to see if 
> the service is up. And if it isnt up, then it starts it. Well I should 
immediately get a 'connection refused' message as the service isnt 
running, however I dont. Instead the resource times out as I
> have startup timeout set to 20 seconds, and connection attempts wont 
give 'connection refused' until after 21 seconds. However I can try to 
connect from another host on the network and I immediately
> get 'connection refused' as expected, even while the box trying to 
connect to itself is still not working.
> 
> But it gets even more interesting. I did a tcpdump on eth0 interface 
(the interface the IPaddr2 resource IP is on) the box running the 
resources and I get the following when resources start up 
> (presumably triggered by the box trying to connect for the status 
check):
>   01:12:21.423330 arp who-has 192.168.2.21 (Broadcast) tell 192.168.2.21
>   01:12:22.428523 arp who-has 192.168.2.21 (Broadcast) tell 192.168.2.21
>   01:12:23.429342 arp who-has 192.168.2.21 (Broadcast) tell 192.168.2.21
> Notice as my box seems to be having a slight identity crisis 
(192.168.2.21 is the IPaddr2 resource)
> 
> Also when I tcpdump on the lo interface I get the following
>   01:15:41.837719 IP 192.168.2.11.37284 > 192.168.2.21.25565: S 
1770941237:1770941237(0) win 32792 <mss 16396,sackOK,timestamp 190131056 
0,nop,wscale 4>
>   01:15:44.845531 IP 192.168.2.11.37284 > 192.168.2.21.25565: S 
1770941237:1770941237(0) win 32792 <mss 16396,sackOK,timestamp 190134064 
0,nop,wscale 4>
> Which indicates that the box clearly isnt responding (192.168.2.11 is 
the box's normal ip)
> 
> As mentioned earlier, after 21 seconds I start getting 'connection 
refused' when attempting to connect. The packets are still going over the 
lo interface at this point, so nothing changes. 
> Additionally an arp reply never does come back on eth0 or lo, it just 
magically starts working.
> I could bump up my timeout to something higher, but i would really 
prefer to get this issue 
solved._______________________________________________

Hm, just an idea. Did you try:

ip route flush cache

There is also the "flush_routes" parameter in ipaddr2, but this is only in 
the "stop" method. Seams your issue is somehow different.

Regards
Alex