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

Cluster deployment modes

RocketMQ supports several high‑availability deployment patterns. Single‑master mode is not recommended for production. Multi‑master options include:

Multiple masters without slaves : simple configuration and highest throughput, but messages on a failed node are unavailable until recovery.

Multiple masters with asynchronous replication slaves : provides data safety and near‑real‑time delivery; a slave failure causes minimal message loss.

Multiple masters with synchronous double‑write slaves : eliminates single points of failure and guarantees zero message delay, at the cost of roughly 10% lower throughput.

This guide demonstrates the asynchronous multi‑master, multi‑slave (2m‑2s‑async) topology using two servers with IPs 192.168.31.186 and 192.168.31.231.

Installation environment

OS: CentOS 7

RocketMQ version: 4.7.0

Java version: JDK 1.8

Step‑by‑step installation

1. Install Java

Download the JDK tarball (e.g., jdk-8u161-linux-x64.tar.gz).

Create a directory and extract the package:

mkdir /usr/local/java
cd /usr/local/java
tar zxvf jdk-8u161-linux-x64.tar.gz

Set environment variables in /etc/profile:

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

Apply the changes: source /etc/profile Verify:

java -version

2. Install NameServer

Create a data directory: mkdir /data Download RocketMQ binary package:

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

Unzip the package: unzip rocketmq-all-4.7.0-bin-release.zip Start NameServer in background:

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

Confirm it is running with jps (look for NamesrvStartup).

3. Install brokers (2‑master‑2‑slave asynchronous replication)

3.1 Broker configuration files

Example master configuration ( broker-a.properties) on 192.168.31.186:

brokerClusterName=rocketmq-cluster
brokerName=broker-a
brokerId=0               # 0 = master
brokerRole=ASYNC_MASTER
flushDiskType=SYNC_FLUSH
listenPort=10911
namesrvAddr=192.168.31.186:9876;192.168.31.231:9876
defaultTopicQueueNums=8
autoCreateTopicEnable=false
autoCreateSubscriptionGroup=false
brokerIP1=192.168.31.186
storePathRootDir=/data/rocketmq-all-4.7.0-bin-release/data/store
storePathCommitLog=/data/rocketmq-all-4.7.0-bin-release/data/store/commitlog
storePathConsumerQueue=/data/rocketmq-all-4.7.0-bin-release/data/store/consumequeue
storePathIndex=/data/rocketmq-all-4.7.0-bin-release/data/store/index
mapedFileSizeCommitLog=1073741824
mapedFileSizeConsumeQueue=300000

Corresponding slave configuration ( broker-b-s.properties) changes brokerId to 1, sets brokerRole=SLAVE, and uses a separate storage path.

3.2 Start brokers

# On 192.168.31.186
nohup sh bin/mqbroker -c conf/2m-2s-async/broker-a.properties &
# On 192.168.31.231
nohup sh bin/mqbroker -c conf/2m-2s-async/broker-b.properties &
# Start slaves
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 Common issues

Memory allocation : If the JVM cannot allocate the default 8 GB heap, edit bin/runbroker.sh and reduce the heap size, e.g.:

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

Port access : Open firewall ports 9876 (NameServer) and 10911, 11011, 10909, 11009 (Brokers).

4. Verification

Check broker logs under /data/rocketmq-all-4.7.0-bin-release/conf/logback_broker.xml for normal startup messages. Use the mqadmin tool to list cluster status:

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

The command outputs each broker’s ID, address, version, and load metrics.

5. Shutdown procedure

sh bin/mqshutdown broker
sh bin/mqshutdown namesrv

6. Optional: Install RocketMQ Console

Install Maven, set MAVEN_HOME and add $MAVEN_HOME/bin to PATH.

Clone the console source:

git clone https://github.com/apache/rocketmq-externals.git

Build the console:

cd rocketmq-externals/rocketmq-console
mvn clean package -Dmaven.test.skip=true

Run the console:

java -jar target/rocketmq-console-ng-1.0.1.jar --rocketmq.config.namesrvAddr='192.168.31.186:9876;192.168.31.231:9876'

Access the UI at http://192.168.31.186:8080 to monitor topics, producers, and consumers.

7. References

RocketMQ Quick Start: http://rocketmq.apache.org/docs/quick-start/

Official documentation (Chinese): https://github.com/apache/rocketmq/tree/master/docs/cn

RocketMQ Console repository: https://github.com/apache/rocketmq-externals/tree/master/rocketmq-console