[ClusterLabs] Antw: Re: Antw: [EXT] Re: Q: effieciently collecting some cluster facts

[Ulrich Windl]

>>> Ken Gaillot <kgaillot at redhat.com> schrieb am 25.02.2021 um 18:43 in
Nachricht
<1ae046f0c3270e5c89a3b6367a3c7255bc6c1eea.camel at redhat.com>:
> I think crm_mon can do nearly all of that:
> 
> * ‑‑daemonize: run continuously in the background
> * ‑‑output‑as: html or xml (or text with the upcoming 2.1.0 release)
> * ‑‑output‑to: any file name
> * ‑‑include/‑‑exclude: limit what sections are displayed, if desired
> (with recent releases)
> * ‑‑resource: limit resource displays to a specific resource, or a
> specific set of resources that have been tagged in the CIB (with 2.0.5)
> 
> The XML output will give an abundance of information, for example about
> DC and quorum:
> 
>  <current_dc present="true"
>              version="2.0.5‑141.2a2d6501b.git.el8‑2a2d6501b"
>              name="rhel8‑3" id="3" with_quorum="true"/>
> 
> and about each node:
> 
>  <node name="cluster01" id="1" online="true"
>        standby="false" standby_onfail="false"
>        maintenance="false" pending="false" unclean="false"
>        shutdown="false" expected_up="true" is_dc="false"
>        resources_running="7" type="member"/>
> 

Yes it's all in the CIB, but parsing XML is not being considered efficient by
me ;-)
In most cases using XML just speeds up global warming ;-)

Regards,
Ulrich

> 
> 
> On Thu, 2021‑02‑25 at 11:26 +0100, Ulrich Windl wrote:
>> Thanks,
>> 
>> I had been expecting some magic user‑level command to be used. C
>> programming is probably efficient, but I#ll have to write another
>> tool first.
>> 
>> It seems the corosync‑quorumtool can also provide the information.
>> Is it correct that the "ring id" has the node id of the DC?
>> Like here (node id 116 is the DC):
>> ‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑
>> Date:             Thu Feb 25 11:24:08 2021
>> Quorum provider:  corosync_votequorum
>> Nodes:            3
>> Node ID:          119
>> Ring ID:          116/42660
>> Quorate:          Yes
>> 
>> Regards,
>> Ulrich
>> 
>> > > > Christine Caulfield <ccaulfie at redhat.com> schrieb am 25.02.2021
>> > > > um 08:22 in
>> 
>> Nachricht <52d91afa‑9b89‑4e2e‑4663‑b1ded39a032e at redhat.com>:
>> > The most efficient way of getting corosync facts about nodes/quorum
>> > is 
>> > to use the votequorum API.
>> > 
>> > see /usr/include/corosync/votequorum.h
>> > and in the corosync sources tarball tests/testvotequorum1.c
>> > 
>> > CHrissie
>> > 
>> > 
>> > On 25/02/2021 07:16, Ulrich Windl wrote:
>> > > Hi!
>> > > 
>> > > I'm thinking about some simple cluster status display that is
>> > > updated 
>> > 
>> > periodically.
>> > > I wonder how to get some "cluster facts" efficiently. Among those
>> > > are:
>> > > 
>> > > * Is corosync running, and how many nodes can be seen?
>> > > * Is Pacemaker running, how many nodes does it see, and does it
>> > > have a 
>> > 
>> > quorum?
>> > > * Is the current node DC?
>> > > * How many resources matching some regular expression are
>> > > running?
>> > > 
>> > > Regards,
>> > > Ulrich
> ‑‑ 
> Ken Gaillot <kgaillot at redhat.com>
> 
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