[ClusterLabs] maximum token value (knet)

[Strahil Nikolov]

I will try to get into the details on monday, when I have access to the cluster again.I guess the /var/log/cluster/corosync.log and /etc/corosync/corosync.conf are the most interesting.
So far, I have 6 node cluster with separate VLANs for HANA replication, prod and backup.Initially, I used pcs to create the corosync.conf with 2 IPs per node, token 40000, consensus 48000 and wait_for_all=1.Later I have expanded the cluster to 3 links and added qnet to the setup (only after I made it run (token 29000) ), so I'm ruling it out.I updated the cluster nodes from RHEL 8.1 to 8.2 , removed the consensus and enabled debug.
As knet is using udp by default, and because the problem is hitting me both in udp (default settings) and sctp - the problem is not in the protocol.
I've also enabled pacemaker blackbox, although I doubt that has any effect on corosync.
How can I enable trace logs for corosync only ?
Best Regards,Strahil Nikolov

 
 
  On Fri, Mar 12, 2021 at 17:01, Jan Friesse<jfriesse at redhat.com> wrote:   Strahil,

> Interesting...
> Yet, this doesn't explain why token of 30000 causes the nodes to never assemble a cluster (waiting for half an hour, using wait_for_all=1) , while setting it to 29000 works like a charm.

Definitively.

Could you please provide a bit more info about your setup 
(config/logs/how many nodes cluster has/...)? Because I've just briefly 
tested two nodes setup with 30 sec token timeout and it was working 
perfectly fine.

> 
> Thankfully we got RH subsciption, so RH devs will provide more detailed output on the issue.

As Jehan correctly noted if it would really get to RH devs it would 
probably get to me ;) But before that GSS will take care of checking 
configs/hw/logs/... and they are really good in finding problems with 
setup/hw/...

> 
> I was hoping that I missed in the documentation about the maximum token size...

Nope.

No matter what, if you can send config/logs/... we may try to find out 
what is root of the problem here on ML or you can really try GSS, but as 
Jehan told, it would be nice if you can post result so other people (me 
included) knows what was the main problem.

Thanks and regards,
  Honza

> 
> Best Regards,
> Strahil Nikolov
> 
> 
> 
> 
> 
> 
> В четвъртък, 11 март 2021 г., 19:12:58 ч. Гринуич+2, Jan Friesse <jfriesse at redhat.com> написа:
> 
> 
> 
> 
> 
> Strahil,
>> Hello all,
>> I'm building a test cluster on RHEL8.2 and I have noticed that the cluster fails to assemble ( nodes stay inquorate as if the network is not working) if I set the token at 30000 or more (30s+).
> 
> Knet waits for enough pong replies for other nodes before it marks them
> as alive and starts sending/receiving packets from them. By default it
> needs to receive 2 pongs and ping is sent 4 times in token timeout so it
> means 15 sec until node is considered up for 30 sec token timeout.
> 
>> What is the maximum token value with knet ?On SLES12 (I think it was  corosync 1) , I used to set the token/consensus with far greater values on some of our clusters.
> 
> I'm really not aware about any arbitrary limits.
> 
> 
>> Best Regards,Strahil Nikolov
>>
> 
> Regards,
> 
>    Honza
> 
>>
>>
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