The vlingo/cluster is a key component that sits on top of vlingo/actors to support the development of scalable and fault-tolerant tools and applications. Additional tools that build out the vlingo/platform will almost always be constructed on top of vlingo/cluster. Additionally, you will implement and deploy your services/applications in clusters.
In addition to scalable fault-tolerance, the vlingo/cluster also provides cluster-wide, synchronizing attributes. This enables the cluster to share live and mutating operational state among all nodes.
Referring to the cluster diagram, if one of the three nodes is lost, the cluster will still maintain a quorum and remain healthy. However, if two nodes are lost and only one node remains in a running state, the quorum is lost and the cluster is considered unhealthy. In that case the one remaining node will enter an idle state and await one or more of the other nodes to return to active operation. When that occurs, the cluster will again constitute a quorum and reach a healthy state. Although many service/application clusters will require only three nodes for optimal use, clusters can support far more than three nodes. Yet, because of the performance and efﬁciencies of our platform, you may rarely need many nodes. Even a 9-node, 21-node, or 49-node cluster may be considered quite large due to our efﬁciency standards.