Demo

Local Cluster Demo

This guide will walk you through setting up a local 3-node Marmot cluster and testing replication capabilities.

Prerequisites

  • Marmot Binary: Ensure you have the marmot-v2 binary built and available.
  • MySQL Client: mysql CLI or any GUI client (DBeaver, etc.).
  • Terminal: A terminal with bash/zsh.

Step 1: Start the Cluster

We will start 3 nodes on your local machine.

Node 1 (Seed Node)

Open a new terminal tab/window and run:

# Node 1: HTTP 8081, MySQL 3307
./marmot-v2 -config cfg/config.toml -cluster-addr :8081 -mysql-port 3307 -node-id 1

Node 2

Open a second terminal tab/window and join the cluster:

# Node 2: HTTP 8082, MySQL 3308
./marmot-v2 -config cfg/config.toml -cluster-addr :8082 -mysql-port 3308 -node-id 2 -seeds localhost:8081

Node 3

Open a third terminal tab/window and join the cluster:

# Node 3: HTTP 8083, MySQL 3309
./marmot-v2 -config cfg/config.toml -cluster-addr :8083 -mysql-port 3309 -node-id 3 -seeds localhost:8081

Note: You should see logs indicating that nodes have joined the cluster and established connections.

Step 2: Test Replication

Now let's verify that data replicates across the cluster.

Connect to Node 1

Open a fourth terminal tab/window:

mysql -h 127.0.0.1 -P 3307 -u root

Run the following SQL:

-- Create a database and table
CREATE DATABASE demo;
USE demo;
CREATE TABLE users (id INT PRIMARY KEY, name VARCHAR(50));
 
-- Insert some data
INSERT INTO users VALUES (1, 'Alice'), (2, 'Bob');

Connect to Node 2

In a new terminal tab (or exit the previous mysql session):

mysql -h 127.0.0.1 -P 3308 -u root

Verify data replication:

USE demo;
SELECT * FROM users;
-- Should show Alice and Bob

Make changes on Node 2:

-- Update a record
UPDATE users SET name = 'Bobby' WHERE id = 2;
 
-- Insert a new record
INSERT INTO users VALUES (3, 'Charlie');

Connect to Node 3

Check Node 3:

mysql -h 127.0.0.1 -P 3309 -u root

Verify all changes:

USE demo;
SELECT * FROM users;
-- Should show:
-- 1 | Alice
-- 2 | Bobby
-- 3 | Charlie

Step 3: Test Fault Tolerance

Let's simulate a node failure.

  1. Kill Node 2: Go to the terminal running Node 2 and press Ctrl+C.
  2. Write to Node 1: 
    INSERT INTO users VALUES (4, 'Dave');
  3. Restart Node 2: Run the same command to start Node 2 again.
  4. Verify Recovery: Connect to Node 2 and check if it caught up. 
    SELECT * FROM users WHERE id = 4;
-- Should show Dave

Marmot's anti-entropy mechanism ensures that Node 2 automatically fetches missing data from peers upon rejoining.

Cleanup

To stop all nodes, simply Ctrl+C in each terminal window. To clean up the data directories:

rm -rf ./marmot-data*
Reference