RocketMQ is a distributed messaging middleware open sourced by Alibaba. An in-depth analysis of its architectural principles is of great significance for understanding RocketMQ's design ideas, usage and performance optimization. This article will conduct an in-depth discussion from two aspects: Broker master-slave high-availability architecture principle and master-slave architecture based on raft protocol.
1. Principle of Broker master-slave high availability architecture
RocketMQ's Broker master-slave high-availability architecture is implemented through the Master-Slave mode. The Master node is responsible for message writing and consumer subscription, and the Slave node is responsible for message backup and reading. When the Master node goes down, the Slave node will automatically take over the work of the Master node to ensure message reliability and high availability.
The implementation principle of Broker master-slave high availability architecture is as follows:
1. The Master node is responsible for message writing and consumer subscription, and at the same time sends messages to the Slave node for backup.
2. The Slave node is responsible for backing up and reading messages. When the Master node goes down, the Slave node will automatically take over the work of the Master node.
3. The Master node and Slave node communicate through the heartbeat mechanism to ensure data synchronization and status synchronization.
4. When the Master node goes down, the Slave node will initiate an election process and elect a new Master node.
5. The new Master node takes over the work of the original Master node, restores services, and ensures message reliability and high availability.
The advantage of the Broker master-slave high-availability architecture is that it can ensure the reliability and high availability of messages. At the same time, the throughput and performance of the system can be improved by adding Slave nodes.
2. Broker’s master-slave architecture based on raft protocol
RocketMQ supports the master-slave architecture based on the raft protocol starting from version 4.3. The raft protocol is a distributed consensus algorithm that can ensure data synchronization and status synchronization between multiple nodes. Implementing the Broker master-slave architecture through the raft protocol can more flexibly manage data synchronization and status synchronization between the Master node and Slave node.
The implementation principle of Broker's master-slave architecture based on the raft protocol is as follows:
1. When the Broker starts, it will automatically elect a Leader node and multiple Follower nodes.
2. The Leader node is responsible for message writing and consumer subscription, and at the same time sends messages to the Follower node for backup.
3. The Follower node is responsible for backing up and reading messages. When the Leader node goes down, the Follower node will automatically take over the work of the Leader node.
4. The Leader node and Follower node communicate through the raft protocol to ensure data synchronization and status synchronization.
5. When the Leader node goes down, the Follower node will initiate the election process and elect a new Leader node.
6. The new Leader node takes over the work of the original Leader node, restores services, and ensures message reliability and high availability.
Broker's master-slave architecture based on the raft protocol has the following advantages compared to the traditional Master-Slave model:
1. More flexible: Follower nodes can be dynamically added or deleted to improve system throughput and performance.
2. More reliable: Data synchronization and status synchronization are ensured through the raft protocol, which can avoid problems such as data loss and brain splitting.
3. More secure: The raft protocol ensures that only the Leader node can write data, avoiding problems such as data conflicts and damage.
Summarize:
RocketMQ is a distributed messaging middleware designed using the Broker master-slave high-availability architecture and the master-slave architecture based on the raft protocol. Through an in-depth analysis of the architectural principles of RocketMQ, you can better understand the design ideas, usage and performance optimization of RocketMQ. At the same time, in actual applications, it is necessary to select an appropriate architecture model according to business needs, and perform reasonable configuration and optimization.