Cluster

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.

Cluster components

Briefly, Helix divides nodes into three logical components based on their responsibilities

Participant

The nodes that host distributed, partitioned resources

Spectator

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).

Controller

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.

Logical view

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.

Using docker images

0. Create a Network

Create an isolated bridge network in docker

docker network create -d bridge pinot-demo

1. Start Zookeeper

Start Zookeeper in daemon.

docker run \
    --network=pinot-demo \
    --name pinot-zookeeper \
    --restart always \
    -p 2181:2181 \
    -d zookeeper:3.5.6

2. Start Zookeeper UI

Start ZKUI to browse Zookeeper data at http://localhost:9090.

docker run \
    --network pinot-demo --name=zkui \
    -p 9090:9090 \
    -e ZK_SERVER=pinot-zookeeper:2181 \
    -d qnib/plain-zkui:latest

Using launcher scripts

Download Pinot Distribution using instructions in Download

1. Start Zookeeper

bin/pinot-admin.sh StartZookeeper -zkPort 2181

2. Start Zooinspector

Install zooinspector to view the data in Zookeeper, and connect to localhost:2181

Once we've started Zookeeper, we can start other components to join this cluster. If you're using docker, pull the latest apachepinot/pinot image.

Using docker images

Pull pinot docker image

You can try out pre-built Pinot all-in-one docker image.

export PINOT_VERSION=latest
export PINOT_IMAGE=apachepinot/pinot:${PINOT_VERSION}
docker pull ${PINOT_IMAGE}

(Optional) You can also follow the instructions here to build your own images.

To start other components to join the cluster

1. Start Controller

2. Start Broker

3. Start Server

Explore your cluster via Pinot Data Explorer