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

Kostiantyn Ponomarenko konstantin.ponomarenko at gmail.com
Wed Nov 23 17:27:01 UTC 2016


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> 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> 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>> wrote:
>> >
>> >     >>> Ken Gaillot <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>>:
>> >     > 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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