MongoDB Replication: Understanding the Primary Node

Identify the Primary Node

Use the MongoDB shell to connect to a replica set and run commands to identify the current primary node.

Expected output: Output showing the replica set status with one member marked as PRIMARY.

Hint: Use the rs.status() command and look for the member with stateStr set to PRIMARY.

Simulate a Primary Failover

Manually step down the primary node and observe the election of a new primary.

Expected output: A new primary node is elected and accepts write operations.

Hint: Use the rs.stepDown() command on the primary node.

The primary node handles all write operations and replicates data changes to secondary nodes to maintain data consistency and availability.

MongoDB replica set members vote in an election process triggered when the current primary is unavailable or a new member joins; the member with the highest priority and most up-to-date data becomes the primary.

If the primary node fails, the replica set members hold an election to select a new primary, ensuring continuous availability without manual intervention.