[Feature] Do not remove Agency members #535
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joerg84
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Mar 23, 2020
ajanikow
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neunhoef
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Mar 23, 2020
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neunhoef
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LGTM. We have discussed this at length: Contrary to what we thought earlier, we now think that any action that might become necessary if an agent with its PV is completely lost, should be with manual interaction. The reason is that this could for example be a network partitition, which might be temporary. Furthermore, a 3 member Raft ensemble can only sustain the loss of a single agent and we must ensure that no bad data loss happens.
Therefore, a human has to order the operation to deploy a new agent with the same ID. One can do this by explicitly deleting the PVC, in which case the operator will recreate a new one and redeploy the pod.
informalict
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Mar 23, 2020
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Difference between action
ActionTypeRemoveMember + ActionTypeAddMemberandActionTypeRecreateMemberis that actionActionTypeRecreateMemberwill not recreate PVC and Member ID - very useful in Ceerdinators to not create zombie Coordinators in cluster and for Agency to persist data in corner cases.