[ClusterLabs] Antw: Re: Set a node attribute for multiple nodes with one command
Kostiantyn Ponomarenko
konstantin.ponomarenko at gmail.com
Thu Dec 1 07:04:27 EST 2016
OK, now I see. I still have a few questions.
1. Is there a good reason to not remove the attribute totally if it is
"deleted"?
2. Does "attrd_updater" sets attributes to "status" configuration
section only?
3. Do I need to modify/set "--delay" to 0 before removing or changing
the attribute? Because now I see that previously set delay works when I
delete the attribute (--delete).
4. Does a delay set only one time work until it's unset (set to 0)?
Thank you,
Kostia
On Wed, Nov 30, 2016 at 10:39 PM, Ken Gaillot <kgaillot at redhat.com> wrote:
> 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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