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: [email protected] > To: [email protected] > > Sure! I'll join the channel! > > > On Wed, Apr 9, 2014 at 12:41 PM, kishore g > <[email protected]<mailto:[email protected]>> 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, > [email protected]<mailto:[email protected]> > <[email protected]<mailto:[email protected]>> 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 > <[email protected]<mailto:[email protected]>> 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: [email protected]<mailto:[email protected]> >> To: [email protected]<mailto:[email protected]> >> >> 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 >> > <[email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>> > > 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 >> > <[email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>> > > 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, >> > [email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>> > >> > <[email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>> > > 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 >> > <[email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>> > > 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, >> > [email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>> > >> > <[email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>> > > 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 >> >> >> >> > > > >
