[ClusterLabs] DC of the election will be an infinite loop.

[Ken Gaillot]

On 06/27/2016 11:41 PM, 飯田 雄介 wrote:
> Hi, all
> 
> I added two lines to comment on cib.xml using crmsh.
> 
> ===
> # cat test.crm
> node 167772452: test-3
> # comment line 1
> # comment line 2
> property cib-bootstrap-options: \
>         have-watchdog=false \
>         dc-version=1.1.14-1.el7-70404b0 \
>         cluster-infrastructure=corosync
> ===
> 
> And was re-start the cluster, the election of the DC was to an infinite loop.
> 
> Environment
> We are using the Pacemaker-1.1.14.
> 
> Where I tried to look at the log,
> It looks like the handling of the comment node is not good.
> It looks like the problem occurs when there are two or more lines of comment.
> 
> Problem seems to occur on or after modification of the following.
> https://github.com/ClusterLabs/pacemaker/commit/1073786ec24f3bbf26a0f6a5b0614a65edac4301
> 
> Does this behavior is a known bug?
> 
> I will attach a crm_report of when the problem occurred.
> 
> Regards,
> Yusuke

This was a tricky one!

In my testing, I found that the behavior occurs only when there is more
than one comment at the same level within a CIB XML element, the
partition has only one node, and the partition does not yet have a DC.

The behavior was indeed introduced in 1.1.14 with the commit you
mentioned. However, there is nothing wrong with that commit! Rather, it
exercised the code differently, triggering other, pre-existing bugs.

I've prepared some fixes which will be merged into the master branch.
Anyone interested in the details can see
https://github.com/ClusterLabs/pacemaker/pull/1099