Igniters, With Vladimir's help, we analyzed another solution's approaches. And decided to simplify our affinity topology auto-adjusting.
It should be enough to be able to turn on/off auto-adjusting (flag) and set 2 timeouts if it is working: -soft timeout which would be used if there was no other node joins/exits; -hard timeout which we would track from first discovery event and if it reached then immediately would change affinity topology. All other strategies could be realized with API usage (setAffinityTopology) and metrics tracking by user's monitoring tools. So, I suggest next API changes: org.apache.ignite.IgniteCluster *Deprecate*: Collection<BaselineNode> currentBaselineTopology(); void setBaselineTopology(Collection<? extends BaselineNode> baselineTop); void setBaselineTopology(long topVer); *Replace them with* Collection<BaselineNode> currentAffinityTopology(); void setAffinityTopology(Collection<? extends BaselineNode> affinityTop); void setAffinityTopology(long topVer); *Add* isAffinityTopologyAutoAdjustEnabled() setAffinityTopologyAutoAdjustEnabled(boolean enabled); org.apache.ignite.configuration.IgniteConfiguration *Add* IgniteConfiguration setAffinityTopologyAutoAdjustEnabled(boolean enabled); IgniteConfiguration setAffinityTopologyAutoAdjustTimeout(long timeoutInMs); IgniteConfiguration setAffinityTopologyAutoAdjustMaxTimeout(long timeoutInMs); An open question is could we rename or duplicate BaselineNode with AffinityNode? On Fri, Apr 27, 2018 at 6:56 PM, Ivan Rakov <ivan.glu...@gmail.com> wrote: > Eduard, > > +1 to your proposed API for configuring Affinity Topology change policies. > Obviously we should use "auto" as default behavior. I believe, automatic > rebalancing is expected and more convenient for majority of users. > > Best Regards, > Ivan Rakov > > > On 26.04.2018 19:27, Eduard Shangareev wrote: > >> Igniters, >> >> Ok, I want to share my thoughts about "affinity topology (AT) changing >> policies". >> >> >> There would be three major option: >> -auto; >> -manual; >> -custom. >> >> 1. Automatic change. >> A user could set timeouts for: >> a. change AT on any topology change after some timeout (setATChangeTimeout >> in seconds); >> b. change AT on node left after some timeout (setATChangeOnNodeLeftTimeout >> in seconds); >> c. change AT on node join after some timeout (setATChangeOnNodeJoinTimeout >> in seconds). >> >> b and c are more specific, so they would override a. >> >> Also, I want to introduce a mechanism of merging AT changes, which would >> be >> turned on by default. >> Other words, if we reached timeout than we would change AT to current >> topology, not that one which was on timeout schedule. >> >> 2. Manual change. >> >> Current behavior. A user change AT himself by console tools or web >> console. >> >> 3. Custom. >> >> We would give the option to set own realization of changing policy (class >> name in config). >> We should pass as incoming parameters: >> - current topology (collection of cluster nodes); >> - current AT (affinity topology); >> - map of GroupId to minimal alive backup number; >> - list of configuration (1.a, 1.b, 1.c); >> - scheduler. >> >> Plus to these configurations, I propose orthogonal option. >> 4. Emergency affinity topology change. >> It would change AT even MANUAL option is set if at least one cache group >> backup factor goes below or equal chosen one (by default 0). >> So, if we came to situation when after node left there was only primary >> partion (without backups) for some cache group we would change AT >> immediately. >> >> >> Thank you for your attention. >> >> >> On Thu, Apr 26, 2018 at 6:57 PM, Eduard Shangareev < >> eduard.shangar...@gmail.com> wrote: >> >> Dmitriy, >>> >>> I also think that we should think about 2.6 as the target. >>> >>> >>> On Thu, Apr 26, 2018 at 3:27 PM, Alexey Goncharuk < >>> alexey.goncha...@gmail.com> wrote: >>> >>> Dmitriy, >>>> >>>> I doubt we will be able to fit this in 2.5 given that we did not even >>>> agree >>>> on the policy interface. Forcing in-memory caches to use baseline >>>> topology >>>> will be an easy technical fix, however, we will need to update and >>>> probably >>>> fix lots of failover tests, add new ones. >>>> >>>> I think it makes sense to target this change to 2.6. >>>> >>>> 2018-04-25 22:25 GMT+03:00 Ilya Lantukh <ilant...@gridgain.com>: >>>> >>>> Eduard, >>>>> >>>>> I'm not sure I understand what you mean by "policy". Is it an interface >>>>> that will have a few default implementations and user will be able to >>>>> create his own one? If so, could you please write an example of such >>>>> interface (how you see it) and how and when it's methods will be >>>>> >>>> invoked. >>>> >>>>> On Wed, Apr 25, 2018 at 10:10 PM, Eduard Shangareev < >>>>> eduard.shangar...@gmail.com> wrote: >>>>> >>>>> Igniters, >>>>>> I have described the issue with current approach in "New definition >>>>>> >>>>> for >>>> >>>>> affinity node (issues with baseline)" topic[1]. >>>>>> >>>>>> Now we have 2 different affinity topology (one for in-memory, another >>>>>> >>>>> for >>>> >>>>> persistent caches). >>>>>> >>>>>> It causes problems: >>>>>> - we lose (in general) co-location between different caches; >>>>>> - we can't avoid PME when non-BLAT node joins cluster; >>>>>> - implementation should consider 2 different approaches to affinity >>>>>> calculation. >>>>>> >>>>>> So, I suggest unifying behavior of in-memory and persistent caches. >>>>>> They should all use BLAT. >>>>>> >>>>>> Their behaviors were different because we couldn't guarantee the >>>>>> >>>>> safety >>>> >>>>> of >>>>> >>>>>> in-memory data. >>>>>> It should be fixed by a new mechanism of BLAT changing policy which >>>>>> >>>>> was >>>> >>>>> already discussed there - "Triggering rebalancing on timeout or >>>>>> >>>>> manually >>>> >>>>> if >>>>> >>>>>> the baseline topology is not reassembled" [2]. >>>>>> >>>>>> And we should have a policy by default which similar to current one >>>>>> (add nodes, remove nodes automatically but after some reasonable delay >>>>>> [seconds]). >>>>>> >>>>>> After this change, we could stop using the term 'BLAT', Basline and so >>>>>> >>>>> on. >>>>> >>>>>> Because there would not be an alternative. So, it would be only one >>>>>> possible Affinity Topology. >>>>>> >>>>>> >>>>>> [1] >>>>>> http://apache-ignite-developers.2346864.n4.nabble. >>>>>> >>>>> com/New-definition-for- >>>>> >>>>>> affinity-node-issues-with-baseline-td29868.html >>>>>> [2] >>>>>> http://apache-ignite-developers.2346864.n4.nabble. >>>>>> com/Triggering-rebalancing-on-timeout-or-manually-if-the- >>>>>> baseline-topology-is-not-reassembled-td29299.html#none >>>>>> >>>>>> >>>>> >>>>> -- >>>>> Best regards, >>>>> Ilya >>>>> >>>>> >>> >
