Cluster
Terms
-
Node
- A logical member of a cluster. There could be multiple nodes on a physical machine. Defined by a hostname:port:uid tuple.
-
Cluster
- A set of nodes joined together through the membership service.
-
Leader
- A single node in the cluster that acts as the leader. Managing cluster convergence and membership state transitions.
Membership Lifecyle
Membership
The cluster membership state is a specialized CRDT, which means that it has a monotonic merge function. When concurrent changes occur on different nodes the updates can always be merged and converge to the same end result.
Network view of a cluster
Initial Cluster State
Deploying 5 nodes
Joining the Cluster
Everyone attempts to Join Seed Nodes
Leader Election
Gossip Protocol begins, marking nodes UP
Ring Formation
Gossip Spreads, Communication stablished with Non-Seed Nodes
Network view of a cluster
Live Demo!
Akka Cluster
By Gabriel Volpe
