How to Build a High‑Availability RocketMQ Cluster on Two Linux Servers

1. Cluster Deployment Options

RocketMQ physical deployment diagram.

Producer and Consumer are applications. NameServer cluster consists of independent instances; deploying two or more ensures high availability. For Broker, several cluster deployment modes are available:

1. Single Master Mode

High risk; not recommended for production, only for local testing.

2. Multi‑Master Mode

All nodes are Masters (e.g., 2 or 3). Advantages: simple configuration, no impact when a Master restarts, high performance with RAID10. Disadvantages: messages on a down machine cannot be consumed until it recovers.

3. Multi‑Master Multi‑Slave (Async Replication)

Each Master has a Slave; HA uses asynchronous replication, causing millisecond‑level delay. Advantages: minimal message loss, transparent failover, performance similar to multi‑master. Disadvantage: possible loss of a few messages if Master fails and disk is damaged.

4. Multi‑Master Multi‑Slave (Sync Dual‑Write)

HA uses synchronous dual‑write; both Master and Slave must write successfully. Advantages: no single point of failure, zero message delay on Master failure. Disadvantage: ~10% lower performance, higher latency, and current version does not auto‑promote Slave after Master crash.

This article shows how to build a high‑availability RocketMQ cluster with dual NameServers, dual Masters, and dual Slaves on two servers (IP 192.168.31.186 and 192.168.31.231).

2. Installation Environment

Linux: CentOS 7

RocketMQ version: 4.7.0

Java version: JDK 1.8

3. Installation Steps

3.1 Install Java

On each server, download the JDK package, upload to /usr/local/java, extract, and configure environment variables.

cd /usr/local/
mkdir java

tar zxvf jdk-8u161-linux-x64.tar.gz

vi /etc/profile

JAVA_HOME=/usr/local/java/jdk1.8.0_161
CLASSPATH=.:$JAVA_HOME/lib/
PATH=$PATH:$JAVA_HOME/bin
export PATH JAVA_HOME CLASSPATH

source /etc/profile

java -version

3.2 Install NameServer

Create data directory, download and unzip RocketMQ, then start NameServer.

mkdir /data

wget https://mirror.bit.edu.cn/apache/rocketmq/4.7.0/rocketmq-all-4.7.0-bin-release.zip

unzip rocketmq-all-4.7.0-bin-release.zip

nohup sh /data/rocketmq-all-4.7.0-bin-release/bin/mqnamesrv &

jps

3.3 Install Brokers

Configure Master and Slave broker property files for each server (examples of broker-a.properties, broker-b.properties, broker-a-s.properties, broker-b-s.properties). Key settings include brokerClusterName, brokerName, brokerId, brokerRole, flushDiskType, listenPort, namesrvAddr, and storage paths.

# Example snippet from broker-a.properties
brokerClusterName=rocketmq-cluster
brokerName=broker-a
brokerId=0
brokerRole=ASYNC_MASTER
flushDiskType=SYNC_FLUSH
listenPort=10911
namesrvAddr=192.168.31.186:9876;192.168.31.231:9876
...

Start Brokers

nohup sh bin/mqbroker -c conf/2m-2s-async/broker-a.properties &

nohup sh bin/mqbroker -c conf/2m-2s-async/broker-b.properties &

nohup sh bin/mqbroker -c conf/2m-2s-async/broker-a-s.properties &

nohup sh bin/mqbroker -c conf/2m-2s-async/broker-b-s.properties &

3.3.1 Memory Issues

If Java cannot allocate memory, reduce JVM heap in bin/runbroker.sh:

JAVA_OPT="${JAVA_OPT} -server -Xms512m -Xmx512m -Xmn512m"

3.3.2 Open Required Ports

NameServer: 9876; Broker: 10911, 11011, 10909, 11009.

3.4 Verification

Check broker.log and use mqadmin to list cluster status.

sh bin/mqadmin clusterList -n "192.168.31.186:9876;192.168.31.231:9876"

3.5 Shutdown

sh bin/mqshutdown broker
sh bin/mqshutdown namesrv

4. Optional: Install rocketmq-console

Install Maven, download rocketmq-externals, build the console, and run it.

wget http://mirrors.cnnic.cn/apache/maven/maven-3/3.5.4/binaries/apache-maven-3.5.4-bin.tar.gz
tar zxvf apache-maven-3.5.4-bin.tar.gz
export MAVEN_HOME=/data/apache-maven-3.5.4
export PATH=$MAVEN_HOME/bin:$PATH
mvn -v

wget https://github.com/apache/rocketmq-externals/archive/refs/heads/master.zip
unzip master.zip
cd rocketmq-externals-master/rocketmq-console/
mvn clean package -Dmaven.test.skip=true
java -jar target/rocketmq-console-ng-1.0.1.jar --rocketmq.config.namesrvAddr='192.168.31.186:9876;192.168.31.231:9876'

Access http://192.168.31.186:8080 to view the console UI.

5. References

http://rocketmq.apache.org/docs/quick-start/
https://github.com/apache/rocketmq/tree/master/docs/cn
https://github.com/apache/rocketmq-externals/tree/master/rocketmq-console