Package net.sodacan.core.coordinator
The Sodacan coordinator keeps a network-wide "ideal" distribution of ActorGroups along with a snapshot of the current Host/ActorGroup arrangement.
In practice, each Host has a coordinator that communicates with other coordinators. Then it's a matter of the local Coordinator working with the local Host to get the current configuration to match the ideal configuration. Details: ITS EASIER SAID THAN DONE
While each Host has a coordinator, all coordinators endeavor to have the same view of the network. Therefore, in other parts Sodacan, when the term "The Coordinator" is used, it can be thought of as a single entity even though each Host has one.
The configuration of the system can change dramatically from time to time. For example, when a Host goes off-line how are the remaining nodes reconfigured to take up the slack. Likewise, when a new or existing node is brought on-line, how are ActorGroups balanced to take advantage of the new resource.
Sodacan's coordinators rely on Apache Zookeeper to maintain these configurations across the network and to provide services such as leader-election, heartbeat function, and change notifications.
ActorGroup View
ActorGroup
Status Normal or Not fully replicated
Backlog (inflight messages vs backpressure point)
Throughput (average messages per second)
Live Host
Hot backup host(s)
Warm backup host(s) if any
Cold backup host(s) if any
Host View
Host
Off-line or On-line
ActorGroups
ActorGroup and Mode (live,hot,warm, cold)
Incident View
ActorGroups not at full replication
Off-line Host(s)
Slow Host(s)
Hosts with low storage
Transition View
Hosts Recently off-line
Hosts Recently On-line
ActorGroup from Cold on Host1 to Warm on Host2 (source ActorGroup on Host3)
ActorGroup from Warm on Host to Hot on Host (local journal to Actor local)
ActorGroup from Hot to Live
Current Live on HostA (if any) to Hot or Warm
Current Hot on HostB... to Live
ActorGroup from Hot to Cold on Host (No heartbeat, off-line, crash)
Current Live on HostA to Cold
Current Hot on HostB... to Live
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ClassDescriptionContains a combination of host number, actorgroup number, and actorGroup state.Active state means that this actorGroup is able to process messages. Replica state means that this actorGroup is only receiving actor state messages and storing them locally in anticipation of possibly becoming active. The Host mode allows the specified ActorGroup to remain bound to the host; It can't move like an ordinary ActorrGroup.For this Single host coordinator, the static configuration is provided and used.