[ClusterLabs] Antw: Re: Set a node attribute for multiple nodes with one command

Kostiantyn Ponomarenko konstantin.ponomarenko at gmail.com
Wed Nov 30 17:31:10 UTC 2016


Hi Ken,

I didn't look into the logs, but I experimented with it for a while.
Here is what I found.

It worked for you because this attribute - "my-attr" - has not ever been
set before in that cluster.

So if you set an attribute, then remove it, and then set it with "--delay",
like:

    # attrd_updater -N node-0 -n my-attr --update false --delay 20

, this delay (dampening) won't work.
Moreover, when you delete this attribute the actual remove will be delayed
by that "--delay" which was used when the attribute was set.


Thank you,
Kostia

On Tue, Nov 29, 2016 at 1:08 AM, Ken Gaillot <kgaillot at redhat.com> wrote:

> On 11/24/2016 05:24 AM, Kostiantyn Ponomarenko wrote:
> > Attribute dampening doesn't work for me also.
> > To test that I have a script:
> >
> >     attrd_updater -N node-0 -n my-attr --update false --delay 20
> >     sleep 3
> >     attrd_updater -N node-0 -n my-attr --update true
> >     sleep 7
> >     attrd_updater -N node-1 -n my-attr --update true
>
> This sequence works for me -- the attributes are not written to the live
> CIB until the end of the delay, when both are written at the same time.
>
> The remaining issue must be with the policy engine. You could look at
> the detail log on the DC when these changes were made; you should see
> info-level messages with the CIB change with both values together (lines
> with "cib_perform_op:   ++" and the attribute values), then "Transition
> aborted" with "Transient attribute change", then a bunch of "pengine:"
> lines saying what the cluster wants to do with each resource.
>
> There should be some information about the scores used to place the
> resources.
>
> >
> > All my resources have this rule in Pacemaker config:
> >
> >     crm configure location res1-location-rule res1 \
> >         rule 0: my-attr eq true \
> >         rule -inf: my-attr ne true
> >
> > On a working two-node cluster I remove "my-attr" from both nodes.
> > Then run my script. And all resources start on node-0.
> > Am I doing something wrong?
> > Or maybe my understanding of an attribute dampening is not correct?
> >
> > My Pacemaker version is 1.1.13. (heh, not the last one, but it is what
> > it is ...)
> >
> > Thank you,
> > Kostia
> >
> > On Wed, Nov 23, 2016 at 7:27 PM, Kostiantyn Ponomarenko
> > <konstantin.ponomarenko at gmail.com
> > <mailto:konstantin.ponomarenko at gmail.com>> wrote:
> >
> >     Maybe I am doing something wrong, but I cannot set "status" section
> >     node attributes to a shadow cib, cluster applies them immediately.
> >     To try it out I do in a console:
> >
> >         crm_shadow --create test
> >         crm_attribute --type nodes --node node-0 --name my-attribute
> >     --update 1 --lifetime=reboot
> >
> >     And this attribute is set to the live cluster configuration
> immediately.
> >     What am I doing wrong?
> >
> >     Thank you,
> >     Kostia
> >
> >     On Tue, Nov 22, 2016 at 11:33 PM, Kostiantyn Ponomarenko
> >     <konstantin.ponomarenko at gmail.com
> >     <mailto:konstantin.ponomarenko at gmail.com>> wrote:
> >
> >         Ken,
> >         Thank you for the explanation.
> >         I will try this low-level way of shadow cib creation tomorrow.
> >         PS: I will sleep much better with this excellent news/idea. =)
> >
> >         Thank you,
> >         Kostia
> >
> >         On Tue, Nov 22, 2016 at 10:53 PM, Ken Gaillot
> >         <kgaillot at redhat.com <mailto:kgaillot at redhat.com>> wrote:
> >
> >             On 11/22/2016 04:39 AM, Kostiantyn Ponomarenko wrote:
> >             > Using "shadow cib" in crmsh looks like a good idea, but it
> doesn't work
> >             > with node attributes set into "status" section of
> Pacemaker config.
> >             > I wonder it it is possible to make it work that way.
> >
> >             Forgot to mention -- the shadow CIB is probably the best way
> >             to do this.
> >             I don't know if there's a way to do it in crmsh, but you can
> >             use it with
> >             the low-level commands crm_shadow and crm_attribute
> >             --lifetime=reboot.
> >
> >             > Ken,
> >             >>> start dampening timer
> >             > Could you please elaborate more on this. I don't get how I
> can set this
> >             > timer.
> >             > Do I need to set this timer for each node?
> >             >
> >             >
> >             > Thank you,
> >             > Kostia
> >             >
> >             > On Mon, Nov 21, 2016 at 9:30 AM, Ulrich Windl
> >             > <Ulrich.Windl at rz.uni-regensburg.de
> >             <mailto:Ulrich.Windl at rz.uni-regensburg.de>
> >             > <mailto:Ulrich.Windl at rz.uni-regensburg.de
> >             <mailto:Ulrich.Windl at rz.uni-regensburg.de>>> wrote:
> >             >
> >             >     >>> Ken Gaillot <kgaillot at redhat.com
> >             <mailto:kgaillot at redhat.com> <mailto:kgaillot at redhat.com
> >             <mailto:kgaillot at redhat.com>>>
> >             >     schrieb am 18.11.2016 um 16:17 in Nachricht
> >             >     <d6f449da-64f8-12ad-00be-e772d8e382ca at redhat.com
> >             <mailto:d6f449da-64f8-12ad-00be-e772d8e382ca at redhat.com>
> >             >
> >              <mailto:d6f449da-64f8-12ad-00be-e772d8e382ca at redhat.com
> >             <mailto:d6f449da-64f8-12ad-00be-e772d8e382ca at redhat.com>>>:
> >             >     > On 11/18/2016 08:55 AM, Kostiantyn Ponomarenko wrote:
> >             >     >> Hi folks,
> >             >     >>
> >             >     >> Is there a way to set a node attribute to the
> >             "status" section for few
> >             >     >> nodes at the same time?
> >             >     >>
> >             >     >> In my case there is a node attribute which allows
> >             some resources to
> >             >     >> start in the cluster if it is set.
> >             >     >> If I set this node attribute for say two nodes in a
> >             way - one and then
> >             >     >> another, than these resources are not distributed
> >             equally between these
> >             >     >> two nodes. That because Pacemaker picks the first
> >             node to with this
> >             >     >> attribute is set and immediately starts all allowed
> >             resources on it. And
> >             >     >> this is not the behavior i would like to get.
> >             >     >>
> >             >     >> Thank you,
> >             >     >> Kostia
> >             >     >
> >             >     > Not that I know of, but it would be a good feature
> >             to add to
> >             >     > attrd_updater and/or crm_attribute.
> >             >
> >             >     With crm (shell) you don't have transactions for node
> >             attributes,
> >             >     but for the configuration. So if you add a location
> >             restriction
> >             >     preventing any resources on your nodes, then enable
> >             the nodes, and
> >             >     then delete the location restrictions in one
> >             transaction, you might
> >             >     get what you want. It's not elegant, but itt ill do.
> >             >
> >             >     To the crm shell maintainer: Is is difficult to build
> >             transactions
> >             >     to node status changes? The problem I see is this: For
> >             configuration
> >             >     you always have transactions (requiring "commit), but
> >             for nodes you
> >             >     traditionally have non (effects are immediate). So
> >             you'd need a
> >             >     thing like "start transaction" which requires a
> >             "commit" or some
> >             >     kind of abort later.
> >             >
> >             >     I also don't know whether a "shadow CIB" would help
> >             for the original
> >             >     problem.
> >             >
> >             >     Ulrich
> >             >
> >             >     >
> >             >     > You can probably hack it with a dampening value of a
> >             few seconds. If
> >             >     > your rule checks for a particular value of the
> >             attribute, set all the
> >             >     > nodes to a different value first, which will write
> >             that value and
> >             >     start
> >             >     > the dampening timer. Then set all the attributes to
> >             the desired value,
> >             >     > and they will get written out together when the
> >             timer expires.
>
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