[ClusterLabs] big trouble with a DRBD resource

[Kristoffer Grönlund]

"Lentes, Bernd" <bernd.lentes at helmholtz-muenchen.de> writes:

> Hi,
>
> first: is there a tutorial or s.th. else which helps in understanding what pacemaker logs in syslog and /var/log/cluster/corosync.log ?
> I try hard to find out what's going wrong, but they are difficult to understand, also because of the amount of information.
> Or should i deal more with "crm histroy" or hb_report ?

I like to use crm history log to get the logs from all the nodes in a
single flow, but it depends quite a bit on configuration what gets
logged where..

>
> What happened:
> I tried to configure a simple drbd resource following http://clusterlabs.org/doc/en-US/Pacemaker/1.1-plugin/html-single/Clusters_from_Scratch/index.html#idm140457860751296
> I used this simple snip from the doc:
> configure primitive WebData ocf:linbit:drbd params drbd_resource=wwwdata \
>     op monitor interval=60s

I'll try to sum up the issues I see, from a glance:

* The drbd resource is a multi-state / master-slave resource, which is
  technically a variant of a clone resource where different clones can
  either be in a primary or secondary state. To configure it correctly,
  you'll need to create a master resource as well. Doing this with a
  single command is unfortunately a bit painful. Either use crm
  configure edit, or the interactive crm mode (with a verify / commit
  after creating both the primitive and the master resources).

* You'll need to create monitor operations for both the master and slave
  roles, as you note below, and set explicit timeouts for all
  operations.

* Make sure the wwwdata DRBD resource exists, is accessible from both
  nodes, and is in a good state to begin with (that is, not
  split-brained).

I would recommend following one of the tutorials provided by Linbit
themselves which show how to set this stuff up correctly, since it is
quite a bit involved.

> Btw: is there a history like in the bash where i see which crm command i entered at which time ? I know that crm history is mighty, but didn't find that.

We don't have that yet :/ If you're not in interactive mode, your bash
history should have the commands though.

> no backup - no mercy

lol ;)

Cheers,
Kristoffer

-- 
// Kristoffer Grönlund
// kgronlund at suse.com