raboof/pekko
1
0
Fork 0
Code Issues Pull requests Projects Releases 6 Packages Wiki Activity Actions 10

Hardening of cluster member leaving path, see #3309

Browse source 
* Removed leader commands for Shutdown and Exit
* Member shutdown itself  when it sees itself as Exiting
* Singleton cluster with status Exiting will shutdown itself,
  in case the Exiting gossip never arrives
* Exiting member not part convergence check
* Exiting member is removed by leader (on convergence) when the
  exiting member is in the unreachable set, i.e. sucessfully shutdown
* Reverted the change made for #3266, i.e. Exiting is
  detected as unreachable again.
* Adjust ClusterSingletonManager to new Exiting behaviour
* Fix bug in HeartbeatSender, which caused it to continue to
  send heartbeats to removed nodes, instead of rebalancing
* Refactoring of leaderActions method
* Leaving section in docs
This commit is contained in:
Patrik Nordwall 2013-05-09 09:49:59 +02:00
parent 85954621ef
commit a0a0f39613
20 changed files with 338 additions and 340 deletions
Download patch file Download diff file Expand all files Collapse all files

30
akka-docs/rst/java/cluster-usage.rst
View file

@ -158,6 +158,26 @@ Be aware of that using auto-down implies that two separate clusters will
automatically be formed in case of network partition. That might be
desired by some applications but not by others.
Leaving
^^^^^^^
There are two ways to remove a member from the cluster.
You can just stop the actor system (or the JVM process). It will be detected
as unreachable and removed after the automatic or manual downing as described
above.
A more graceful exit can be performed if you tell the cluster that a node shall leave.
This can be performed using :ref:`cluster_jmx_java` or :ref:`cluster_command_line_java`.
It can also be performed programatically with ``Cluster.get(system).leave(address)``.
Note that this command can be issued to any member in the cluster, not necessarily the
one that is leaving. The cluster extension, but not the actor system or JVM, of the
leaving member will be shutdown after the leader has changed status of the member to
`Exiting`. Thereafter the member will be removed from the cluster. Normally this is handled
automatically, but in case of network failures during this process it might still be necessary
to set the node’s status to ``Down`` in order to complete the removal.
.. _cluster_subscriber_java:
Subscribe to Cluster Events
@ -168,7 +188,15 @@ You can subscribe to change notifications of the cluster membership by using
``akka.cluster.ClusterEvent.CurrentClusterState``, is sent to the subscriber
as the first event, followed by events for incremental updates.
There are several types of change events, consult the API documentation
The events to track the life-cycle of members are:
* ``ClusterEvent.MemberUp`` - A new member has joined the cluster and its status has been changed to ``Up``.
* ``ClusterEvent.MemberExited`` - A member is leaving the cluster and its status has been changed to ``Exiting``.
Note that the node might already have been shutdown when this event is published on another node.
* ``ClusterEvent.MemberRemoved`` - Member completely removed from the cluster.
* ``ClusterEvent.UnreachableMember`` - A member is considered as unreachable by the failure detector.
There are more types of change events, consult the API documentation
of classes that extends ``akka.cluster.ClusterEvent.ClusterDomainEvent``
for details about the events.