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

Kostiantyn Ponomarenko konstantin.ponomarenko at gmail.com
Wed Nov 30 17:34:48 UTC 2016


>> Moreover, when you delete this attribute the actual remove will be
delayed by that "--delay" which was used when the attribute was set.
I wasn't clear here. The behavior described in this line happens only when
"dampening" has worked out during the attribute set-up.

Thank you,
Kostia

On Wed, Nov 30, 2016 at 7:31 PM, Kostiantyn Ponomarenko <
konstantin.ponomarenko at gmail.com> wrote:

> 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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