Part 2: Installation & Cluster Setup

Theory is great, but let’s get our hands dirty. We’re going to spin up a 3-node CockroachDB cluster on your local machine using Docker.

Why 3 Nodes?

You can run a single node, but that’s boring. CockroachDB shines when it’s distributed. With 3 nodes, we can simulate failures and see how the cluster self-heals.

Step 1: Create a Network

First, let’s create a Docker network so our nodes can talk to each other.

docker network create -d bridge roachnet

Step 2: Start the Nodes

Run these commands to start three nodes:

# Node 1
docker run -d --name=roach1 --hostname=roach1 --net=roachnet -p 26257:26257 -p 8080:8080 cockroachdb/cockroach:latest start-single-node --insecure

# Wait... actually, let's do a proper 3-node cluster.
# Stop that single node first if you ran it.

# Node 1
docker run -d --name=roach1 --hostname=roach1 --net=roachnet -p 26257:26257 -p 8080:8080 cockroachdb/cockroach:latest start --insecure --join=roach1,roach2,roach3

# Node 2
docker run -d --name=roach2 --hostname=roach2 --net=roachnet cockroachdb/cockroach:latest start --insecure --join=roach1,roach2,roach3

# Node 3
docker run -d --name=roach3 --hostname=roach3 --net=roachnet cockroachdb/cockroach:latest start --insecure --join=roach1,roach2,roach3

Step 3: Initialize the Cluster

The nodes are running, but they aren’t a cluster yet. We need to tell them to join forces.

docker exec -it roach1 ./cockroach init --insecure

You should see: Cluster successfully initialized.

Step 4: Access the Dashboard

Open your browser and go to http://localhost:8080. You’ll see the beautiful DB Console showing 3 live nodes.

Conclusion

You now have a distributed database running on your laptop. In the next part, we’ll connect to it using SQL and see how it compares to Postgres.