[ClusterLabs] Antw: Re: Command to show location constraints?

Ulrich Windl Ulrich.Windl at rz.uni-regensburg.de
Wed Aug 28 04:27:39 EDT 2019

>>> Jan Pokorný <jpokorny at redhat.com> schrieb am 28.08.2019 um 10:03 in
<20190828080347.GA9493 at redhat.com>:
> On 27/08/19 09:24 ‑0600, Casey & Gina wrote:
>> Hi, I'm looking for a way to show just location constraints, if they
>> exist, for a cluster.  I'm looking for the same data shown in the
>> output of `pcs config` under the "Location Constraints:" header, but
>> without all the rest, so that I can write a script that checks if
>> there are any set.
>> The situation is that sometimes people will perform a failover with
>> `pcs resource move ‑‑master <resource>`, but then forget to follow
>> it up with `pcs resource clear <resource>`, and then it causes
>> unnecessary failbacks later.  As we never want to have any
>> particular node in the cluster preferred for this resource, I'd like
>> to write a script that can automatically check for any location
>> constraints being set and either alert or clear it automatically.
> One could also think of "crm_resource ‑‑clear ‑‑dry‑run" that doesn't
> exist yet.  Please, file a RFE with https://bugs.clusterlabs.org if
> this would be useful.

Thinking about it: Location constraints can have an expire timestamp, but they
don't have a creation timestamp (AFAIK). This the first step in automatically
cleaning up location constraints that don't have an expiration time set would
be adding a creation time stamp.
The next step would be a definition of a "maximum location constraint
and finally actual code that removes location constraints that exceeded their

Thinking about it: There may be a more pleasing solution for the current code
base: Define a maximum lifetime for any migration constraint, and use that if
the user did not specify one.
(The constrains would still linger around, but would not have an effect any


> ‑‑ 
> Jan (Poki)

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