[ClusterLabs] Antw: Re: Set a node attribute for multiple nodes with one command
Ken Gaillot
kgaillot at redhat.com
Wed Nov 30 21:39:27 CET 2016
On 11/30/2016 11:31 AM, Kostiantyn Ponomarenko 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.
Once set, attributes are not truly deleted -- only their values are
cleared. And --delay has no effect with --update if the attribute
already exists, which is what you see above.
To set a delay on an already existing attribute, you have to use
attrd_updater --update-delay or --update-both.
> 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
> <mailto: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>
> > <mailto: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>
> > <mailto: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>
> <mailto: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>>
> > > <mailto: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>> <mailto: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>>
> > >
> >
> <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
> <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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