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From kishore g <g.kish...@gmail.com>
Subject Re: keeping the master node up during bootstrap
Date Thu, 10 Apr 2014 04:16:26 GMT
Hi Vlad,

Here is the diff https://reviews.apache.org/r/20196/diff for the fix and
the test case. If you want to give it a try. Apply this on the master.

thanks,
Kishore G


On Wed, Apr 9, 2014 at 1:40 PM, Kanak Biscuitwala <kanak.b@hotmail.com>wrote:

>
> Based on the result of the conversation, we found the following:
>
> 1. 0.6.x doesn't support partition constraints. Created
> https://issues.apache.org/jira/browse/HELIX-426
> 2. 0.7.x doesn't honor partition constraints correctly. Created
> https://issues.apache.org/jira/browse/HELIX-425
>
> We will try to fix these tomorrow.
>
> Kanak
> ________________________________
> > Date: Wed, 9 Apr 2014 12:51:10 -0700
> > Subject: Re: keeping the master node up during bootstrap
> > From: vlad.gm@gmail.com
> > To: user@helix.apache.org
> >
> > Sure! I'll join the channel!
> >
> >
> > On Wed, Apr 9, 2014 at 12:41 PM, kishore g
> > <g.kishore@gmail.com<mailto:g.kishore@gmail.com>> wrote:
> > Hi Vlad,
> >
> > I have some questions. Can you join the IRC channel #apachehelix.
> >
> > thanks,
> > Kishore G
> >
> >
> > On Wed, Apr 9, 2014 at 11:35 AM,
> > vlad.gm@gmail.com<mailto:vlad.gm@gmail.com>
> > <vlad.gm@gmail.com<mailto:vlad.gm@gmail.com>> wrote:
> > Upon some further testing, it seems that the controller does not
> > execute the events in the right sequence.
> >
> > Here are the results of some of my testing. Assume that we have a
> > partition NEWPROFILE_5 with the ideal state:
> >
> > "NEWPROFILE_5" : {
> >
> > "pf1.apps-pf.dev.docker_12000" : "SLAVE",
> >
> > "pf2.apps-pf.dev.docker_12000" : "MASTER"
> >
> > }
> >
> > I boot the host pf1 and a few minutes later the host pf2. In the
> > controller logs I see, when doing a grep for NEWPROFILE_5:
> >
> > 2014-04-08 17:04:35,309 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message 69b4eddf-ac5f-4726-9d6b-bac742ad082e to
> > pf1.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:SLAVE
> > to:MASTER
> >
> > 2014-04-08 17:27:08,187 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message a221b1ac-0807-425e-9062-6507e45b0bfb to
> > pf1.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:OFFLINE
> > to:BOOTSTRAP
> >
> > 2014-04-08 17:27:10,164 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message 73ed85fd-49c9-46a5-b262-687d612c7d06 to
> > pf1.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:BOOTSTRAP
> > to:SLAVE
> >
> > 2014-04-08 17:27:11,868 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message fb21aecc-68cf-4b9f-9718-aa6ed535c29d to
> > pf1.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:SLAVE
> > to:MASTER
> >
> > 2014-04-08 17:28:22,978 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message ea441d18-b1f3-4ceb-96a2-3262cab1dfbe to
> > pf2.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:OFFLINE
> > to:BOOTSTRAP
> >
> > 2014-04-08 17:28:22,978 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message f36b4d64-c790-413b-b9fa-915b9539d28c to
> > pf1.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:MASTER
> > to:SLAVE
> >
> > 2014-04-08 17:28:26,065 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message 201429e1-e810-4017-b3ef-fb5930ac2192 to
> > pf2.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:BOOTSTRAP
> > to:SLAVE
> >
> > 2014-04-08 17:28:28,238 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message 4a1fb64c-1063-4e49-a995-946d2dd25733 to
> > pf2.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:SLAVE
> > to:MASTER
> >
> > That is, the controller issues an offline->bootstrap command to pf-2,
> > but then issues a master->slave command to of-1 before bringing pf-2 up
> > as a slave as well (the last step before promotion to master). Since
> > the bootstrap->slave that follows takes time, the system spends time
> > without a master for the partition.
> >
> > The state model definition was:
> > public static StateModelDefinition defineStateModel() {
> > StateModelDefinition.Builder builder =
> > new StateModelDefinition.Builder(KVHelixDefinitions.STATE_MODEL_NAME);
> > // Add states and their rank to indicate priority. Lower the rank higher
> the
> > // priority
> > builder.addState(MASTER, 1);
> > builder.addState(SLAVE, 2);
> > builder.addState(BOOTSTRAP, 3);
> > builder.addState(OFFLINE);
> > builder.addState(DROPPED);
> > // Set the initial state when the node starts
> > builder.initialState(OFFLINE);
> >
> > // Add transitions between the states.
> > builder.addTransition(OFFLINE, BOOTSTRAP, 3);
> > builder.addTransition(BOOTSTRAP, SLAVE, 2);
> > builder.addTransition(SLAVE, MASTER, 1);
> > builder.addTransition(MASTER, SLAVE, 4);
> > builder.addTransition(SLAVE, OFFLINE, 5);
> > builder.addTransition(OFFLINE, DROPPED, 6);
> >
> > // set constraints on states.
> > // static constraint
> > builder.upperBound(MASTER, 1);
> > // dynamic constraint, R means it should be derived based on the
> replication
> > // factor.
> > builder.dynamicUpperBound(SLAVE, "R");
> >
> > StateModelDefinition statemodelDefinition = builder.build();
> >
> > assert(statemodelDefinition.isValid());
> >
> > return statemodelDefinition;
> > }
> >
> > I have tried reversing the values of the transition priorities. In this
> > case, the controller log file looked as follows:
> >
> > 2014-04-09 11:17:52,831 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message 2b29a319-c1c6-4042-b1ad-3e3c1b5092a7 to
> > pf1.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:OFFLINE
> > to:BOOTSTRAP
> >
> > 2014-04-09 11:17:55,672 (Thread-2) MessageGenerationStage INFO: Message
> > hasn't been removed for pf1.apps-pf.dev.docker_12000 to
> > transitNEWPROFILE_5 to BOOTSTRAP, desiredState: MASTER
> >
> > 2014-04-09 11:17:57,047 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message b1ca701d-65f1-46b9-9ae4-286400d6d266 to
> > pf1.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:BOOTSTRAP
> > to:SLAVE
> >
> > 2014-04-09 11:17:58,888 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message fe10228f-8f5b-4133-964a-5f6c7e60b0e6 to
> > pf1.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:SLAVE
> > to:MASTER
> >
> > 2014-04-09 11:23:26,117 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message 6252a4e6-0ab8-490a-a51d-c47195c434b5 to
> > pf1.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:MASTER
> > to:SLAVE
> >
> > 2014-04-09 11:23:26,117 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message 18bbf028-cb51-4162-8226-a6564a121986 to
> > pf2.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:OFFLINE
> > to:BOOTSTRAP
> >
> > 2014-04-09 11:23:33,462 (Thread-2) MessageGenerationStage INFO: Message
> > hasn't been removed for pf2.apps-pf.dev.docker_12000 to
> > transitNEWPROFILE_5 to BOOTSTRAP, desiredState: MASTER
> >
> > 2014-04-09 11:23:33,892 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message c7fc4983-9d71-4dc4-bfee-2ad69e4de411 to
> > pf2.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:BOOTSTRAP
> > to:SLAVE
> >
> > 2014-04-09 11:23:35,933 (Thread-2) TaskAssignmentStage INFO: Sending
> > Message 75e715ed-3d53-4e39-b1e7-44695e4bfa03 to
> > pf2.apps-pf.dev.docker_12000 transit NEWPROFILE_5|[] from:SLAVE
> > to:MASTER
> >
> > That is, the transition for master->slave for pf1 was executed before
> > taking any action on pf2, clearly the opposite of the right order.
> >
> >
> > On Tue, Apr 8, 2014 at 2:19 PM, Kanak Biscuitwala
> > <kanak.b@hotmail.com<mailto:kanak.b@hotmail.com>> wrote:
> >
> > Looks good, thanks for sharing!
> >
> > Kanak
> > ________________________________
> >> Date: Tue, 8 Apr 2014 14:08:28 -0700
> >> Subject: Re: keeping the master node up during bootstrap
> >> From: vlad.gm@gmail.com<mailto:vlad.gm@gmail.com>
> >> To: user@helix.apache.org<mailto:user@helix.apache.org>
> >>
> >> My modified code looks like:
> >>
> >> /* Setup a Helix cluster for the KVStore */
> >> public static void setupCluster() {
> >> assert(cluster != null);
> >> clusterSetup.addCluster(cluster, true);
> >>
> >> а а а а ConstraintItemBuilder constraintItemBuilder = new
> >> ConstraintItemBuilder();
> >>
> >> а а а а constraintItemBuilder
> >> а а а а а а а а
> >> .addConstraintAttribute(ConstraintAttribute.MESSAGE_TYPE.toString(),
> >> "STATE_TRANSITION")
> >> а а а а а а а а
> >> .addConstraintAttribute(ConstraintAttribute.PARTITION.toString(), ".*")
> >> а а а а а а а а
> >> .addConstraintAttribute(ConstraintAttribute.CONSTRAINT_VALUE.toString(),
> >> "1");
> >>
> >> а а а а clusterSetup.getClusterManagementTool().setConstraint(cluster,
> >> а а а а а а а а ClusterConstraints.ConstraintType.MESSAGE_CONSTRAINT,
> >> а а а а а а а а "constraint1", constraintItemBuilder.build());
> >> а а }
> >>
> >> I will try to see whether it works in every situation.
> >>
> >> Regards,
> >> Vlad
> >>
> >>
> >> On Tue, Apr 8, 2014 at 8:59 AM, Vlad Balan
> >>
> > <vlad.gm@gmail.com<mailto:vlad.gm@gmail.com><mailto:vlad.gm@gmail.com
> <mailto:vlad.gm@gmail.com>>>
> > wrote:
> >> Hi Kishore,
> >>
> >> I managed to implement the bootstrapping using the constraint and it
> >> appears to be running as expected. I will post my code shortly.
> >>
> >> Regards,
> >> Vlad
> >>
> >> On Apr 8, 2014, at 8:27 AM, kishore g
> >>
> > <g.kishore@gmail.com<mailto:g.kishore@gmail.com><mailto:
> g.kishore@gmail.com<mailto:g.kishore@gmail.com>>>
> > wrote:
> >>
> >> Hi Vlad,
> >>
> >> Did you get a chance to play with the constraint.а I can write a sample
> >> code today to try this.
> >>
> >> Thanks,
> >> Kishore G
> >>
> >>
> >> On Thu, Apr 3, 2014 at 5:45 PM,
> >>
> > vlad.gm@gmail.com<mailto:vlad.gm@gmail.com><mailto:vlad.gm@gmail.com
> <mailto:vlad.gm@gmail.com>>
> >>
> > <vlad.gm@gmail.com<mailto:vlad.gm@gmail.com><mailto:vlad.gm@gmail.com
> <mailto:vlad.gm@gmail.com>>>
> > wrote:
> >>
> >> Thank you Kanak and Kishore! I will try enforcing the per-partition
> >> constraint and let you know if somehow it does not work. I was looking
> >> at the throttling documentation, but somehow missed that a
> >> per-partition constraint was an option!
> >>
> >> Regards,
> >> Vlad
> >>
> >>
> >> On Thu, Apr 3, 2014 at 5:42 PM, kishore g
> >>
> > <g.kishore@gmail.com<mailto:g.kishore@gmail.com><mailto:
> g.kishore@gmail.com<mailto:g.kishore@gmail.com>>>
> > wrote:
> >> Hi Vlad,
> >>
> >> You can try setting the transition priority order and a constraint that
> >> there should be only one transition per partition across the cluster.
> >>
> >> So the transition priority could be something like
> >>
> >> Slave-Master
> >> Offfline -> Bootstrap
> >> Bootstrap->Slave
> >> Slave->Master
> >>
> >> For the rest not sure if order matters.
> >>
> >> Also set the max transitions constraint to 1 per partition.
> >>
> >> The reason I put Slave-Master before Offline->Bootstrap is to ensure
> >> that availability is given more importance. For example if you have 3
> >> nodes, N1, N2, N3. N1 is Master, N2 is Slave, and N3 is down. If N1
> >> goes down and N3 comes up at the same time. We probably dont want to
> >> wait for N3 to bootstrap before promoting N2 to Master.
> >>
> >> I haven't tested this but assuming the constraints enforcement works,
> >> this should do the trick.
> >>
> >> Does this make sense? Let me know if this does not work, we can add a
> >> test case.
> >>
> >> thanks,
> >> Kishore G
> >>
> >>
> >>
> >>
> >>
> >>
> >> On Thu, Apr 3, 2014 at 4:57 PM,
> >>
> > vlad.gm@gmail.com<mailto:vlad.gm@gmail.com><mailto:vlad.gm@gmail.com
> <mailto:vlad.gm@gmail.com>>
> >>
> > <vlad.gm@gmail.com<mailto:vlad.gm@gmail.com><mailto:vlad.gm@gmail.com
> <mailto:vlad.gm@gmail.com>>>
> > wrote:
> >>
> >> Dear all,
> >>
> >> I am trying to construct a state model with the following transition
> > diagram:
> >>
> >> OFFLINE -> BOOTSTRAPPING <---> SLAVE <-----> MASTER
> >> а а а а а<-----------------------------------
> >>
> >> That is, an offline mode can go into a bootstraping state, from the
> >> bootstrap state it can go into a slave state,
> >> from slave it can go from master, from master to slave and from slave
> >> it can go offline.
> >>
> >> Assume that if I have a partition with two nodes pf1 and pf2 and a
> >> partition partition_0 with the following ideal state:
> >>
> >> partition_0: pf2: MASTER pf1: SLAVE,
> >>
> >> and that currently pf1 is serving as a master. When pf2 boots, Helix
> >> will issue, almost simultaneously, two commands:
> >> for pf1: transition from MASTER to SLAVE
> >> for pf2: transition from BOOTSTRAPPING to SLAVE
> >>
> >> My understanding is that this happens since Helix is trying to execute
> >> as many commands in parallel and since the last state
> >> has pf2 as master. However, the transition from BOOTSTRAPPING to SLAVE
> >> for pf2 involves a long data copy step, so
> >> I would like to keep pf1 as a master in the meanwhile. I tried
> >> prioritizing the transition from BOOTSTRAPPING to SLAVE
> >> over the transition from MASTER to SLAVE, however Helix still issues
> >> them in parallel (as it should).
> >>
> >> I was wondering what my options would be in order to keep the master up
> >> while the future master is bootstrapping. Could
> >> a throttling in the number of transitions be enforced at partition
> >> level? Could I somehow specify that a state with a slave
> >> and a bootstrapping node is undesirable?
> >>
> >> As a note, I have also looked at the RSync-replicateed filesystem
> >> example. The reason for not using the OfflineOnline or the
> >> MasterSlave model in my application is that I would like the
> >> bootstrapping node to receive updates from clients, i.e. be visible
> >> during the bootstrap. For this reason, I am introducing the new
> >> BOOTSTRAPPING phase in-between OFFLINE and SLAVE.
> >>
> >> Regards,
> >> Vlad
> >>
> >>
> >> PS: The state model definition is as follows:
> >>
> >> builder.addState(MASTER, 1); а а а а а а а а а а а а а а а а
а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а
> >>
> >> а а а а а а builder.addState(SLAVE, 2);а а а а а а а а а а а
а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.addState(BOOTSTRAP, 3);а а а а а а а а а
а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.addState(OFFLINE); а а а а а а а а а а а
а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.addState(DROPPED); а а а а а а а а а а а
а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а // Set the initial state when the node startsа а а а а
а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.initialState(OFFLINE); а а а а а а а а а
а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> аа а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а // Add transitions between the states. а а а а а а а
а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.addTransition(OFFLINE, BOOTSTRAP, 4);а а а а а
а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.addTransition(BOOTSTRAP, SLAVE, 5);а а а а а
а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.addTransition(SLAVE, MASTER, 6); а а а а а а
а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.addTransition(MASTER, SLAVE, 3); а а а а а а
а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.addTransition(SLAVE, OFFLINE, 2);а а а а а а
а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.addTransition(OFFLINE, DROPPED, 1);а а а а а
а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> аа а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а // set constraints on states.а а а а а а а а а а
а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а // static constraint а а а а а а а а а а а а а
а а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.upperBound(MASTER, 1); а а а а а а а а а
а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а // dynamic constraint, R means it should be derived based
> >> on the replication а а а а а а а а а а а а а а а а а а а
а а а а а а а
> >> а а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а // factor. а а а а а а а а а а а а а а а а
а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а а а а а а а а а
а а а а а а а а а а
> >> а а а а а а а а а а а а а а а а а а
> >>
> >> а а а а а а builder.dynamicUpperBound(SLAVE, "R");а а а а а а а
а а а а
> >>
> >>
> >>
> >>
> >
> >
> >
> >
>
>

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