[ClusterLabs] Antw: [EXT] Suggestions for multiple NFS mounts as LSB script

[Ulrich Windl]

>>> Tony Stocker <akostocker at gmail.com> schrieb am 29.06.2020 um 15:15 in
Nachricht
<31558_1593436561_5EF9E991_31558_332_1_CACLi31XRhAm41CczAS9yoHadd+y6ByBTt7YWXrF_
P4FFv147Q at mail.gmail.com>:
> Hello
> 
> We have a system which has become critical in nature and that
> management wants to be made into a high‑available pair of servers. We
> are building on CentOS‑8 and using Pacemaker to accomplish this.
> 
> Without going into too much detail as to why it's being done, and to
> avoid any comments/suggestions about changing it which I cannot do,
> the system currently uses a script (which is not LSB compliant) to
> mount 133 NFS mounts. Yes, it's a crap ton of NFS mounts. No, I cannot
> do anything to alter, change, or reduce it. I must implement a
> Pacemaker 2‑node high‑availability pair which mounts those 133 NFS
> mounts. This list of mounts also changes over time as some are removed
> (rarely) and others added (much too frequently) and occasionally
> changed.
> 
> It seems to me that manually putting each individual NFS mount in
> using the 'pcs' command as an individual ocf:heartbeat:FileSystem
> resource would be time‑consuming and ultimately futile given the
> frequency of changes.

You could construct a script that generates the commands needed, so it would
be rather easy to handle.

> 
> Also, the reason that we don't put all of these mounts in the
> /etc/fstab file is to speed up boot times and ensure that the systems
> can actually come up into a useable state (and not hang forever)
> during a period when the NFS mounts might not be available for
> whatever reason (e.g. archive maintenance periods.)

Have you considered using automount? It's like fstab, but won't mount
automatically.

> 
> So, I'm left with trying to turn my coworker's bare minimum bash
> script that mounts these volumes into a functional LSB script. I've
> read:
>
https://www.clusterlabs.org/pacemaker/doc/en‑US/Pacemaker/2.0/html/Pacemaker_

> Explained/_linux_standard_base.html
> and
>
http://refspecs.linux‑foundation.org/LSB_3.0.0/LSB‑Core‑generic/LSB‑Core‑generic/

> iniscrptact.html
> 
> My first question is: is there any kind of script within the Pacemaker
> world that one can use to verify that one's script passes muster and
> is compliant without actually trying to run it as a resource? ~8 years
> ago there used to be a script called ocf‑tester that one used to check
> OCF scripts, but I notice that that doesn't seem to be available any
> more ‑ and really I need one for Pacemaker‑compatible LSB script
> testing.
> 
> Second, just what is Pacemaker expecting from the script? Does it
> 'exercise' it looking for all available options? Or is it simply
> relying on it to provide the correct responses when it calls 'start',
> 'stop', and 'status'?

If you decide to continue with the script, I would convert it to an OCF RA
agent (according to docs). It's actually not too difficult, and you can have
automated testing via ocf-tester.

The most interesting part seems to be the question whow you define (and
detect) a failure that will cause a node switch.

Regards,
Ulrich



> 
> Thanks in advance for help.
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