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Discovery: back port #7558 to 1.x and add bwc protections of the new ping on master gone introduced in #7493 #7694

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Discovery: back port #7558 to 1.x and add bwc protections of the new ping on master gone introduced in #7493 #7694

wants to merge 6 commits into from

Commits on Sep 16, 2014

  1. Resiliency: Master election should demotes nodes which try to join th… 

    …e cluster for the first time

With the change in elastic#7493,  we introduced a pinging round when a master nodes goes down. That pinging round helps validating the current state of the cluster and takes, by default, 3 seconds. It may be that during that window, a new node tries to join the cluster and starts pinging (this is typical when you quickly restart the current master).  If this node gets elected as the new master it will force recovery from the gateway (it has no in memory cluster state), which in turn will cause a full cluster shard synchronisation. While this is not a problem on it's own, it's a shame. This commit demotes "new" nodes during master election so the will only be elected if really needed.

Closes elastic#7558
    @bleskes
    bleskes committed Sep 16, 2014
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  2. Discovery: back port elastic#7558 to 1.x and add bwc protections of t… 

    …he new ping on master gone introduced in elastic#7493

The change in elastic#7558 adds a flag to PingResponse. However, when unicast discovery is used,  this extra flag can not be serialized by the very initial pings as they do not know yet what node version they ping (i.e., they have to default to 1.0.0, which excludes changing the serialization format). This commit bypasses this problem by adding a dedicated action which only exist on nodes of version 1.4 or up. Nodes first try to ping this endpoint using 1.4.0 as a serialization version. If that fails they fall back to the pre 1.4.0 action. This is optimal if all nodes are on 1.4.0 or higher, with a small down side if the cluster has mixed versions - but this is a temporary state.

Further two bwc protections are added:
1) Disable the preference to nodes who previously joined the cluster if some of the pings are on version < 1.4.0
2) Disable the rejoin on master gone functionality if some nodes in the cluster or version < 1.4.0
    @bleskes
    bleskes committed Sep 16, 2014
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  3. feedback

    @bleskes
    bleskes committed Sep 16, 2014
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  4. 1_4_0->1_4_0_beta

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    bleskes committed Sep 16, 2014
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  5. last feedback

    @bleskes
    bleskes committed Sep 16, 2014
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  6. fix NPE when sending old pings between new nodes

    @bleskes
    bleskes committed Sep 16, 2014
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