Cluster is a set of nodes comprising of servers, brokers, controllers and minions.
Pinot cluster components
Pinot leverages Apache Helix for cluster management. Helix is a cluster management framework to manage replicated, partitioned resources in a distributed system. Helix uses Zookeeper to store cluster state and metadata.
Briefly, Helix divides nodes into three logical components based on their responsibilities
The nodes that host distributed, partitioned resources
The nodes that observe the current state of each Participant and use that information to access the resources. Spectators are notified of state changes in the cluster (state of a participant, or that of a partition in a participant).
The node that observes and controls the Participant nodes. It is responsible for coordinating all transitions in the cluster and ensuring that state constraints are satisfied while maintaining cluster stability.
Pinot Servers are modeled as Participants, more details about server nodes can be found in Server.
Pinot Brokers are modeled as Spectators, more details about broker nodes can be found in Broker.
Pinot Controllers are modeled as Controllers, more details about controller nodes can be found in Controller.
Another way to visualize the cluster is a logical view, wherein a cluster contains tenants, tenants contain tables, and tables contain segments.
Setup a Pinot Cluster
Typically, there is only one cluster per environment/data center. There is no needed to create multiple Pinot clusters since Pinot supports the concept of tenants. At LinkedIn, the largest Pinot cluster consists of 1000+ nodes.
To setup a Pinot cluster, we need to first start Zookeeper.