What's Actually Happening

ActiveMQ message broker is down or not accepting connections.

The Error You'll See

```bash $ ./activemq status

ActiveMQ Broker is not running ```

Why This Happens

  1. 1.OOM crash - Memory limit exceeded
  2. 2.Store corruption - KahaDB corrupted
  3. 3.Port conflict - Port already in use
  4. 4.Config error - Invalid configuration

Step 1: Check Logs

```bash # Check broker logs: tail -f data/activemq.log

# Look for errors: grep -i error data/activemq.log ```

Step 2: Check Memory

```bash # Check system memory: free -m

# Check Java heap: # In activemq.conf: ACTIVEMQ_OPTS_MEMORY="-Xms1G -Xmx2G" ```

Step 3: Fix Store Corruption

```bash # Check KahaDB: ls -la data/kahadb/

# If corrupted, delete and restart: rm -rf data/kahadb/* ./activemq start ```

Step 4: Start Broker

```bash # Start: ./activemq start

# Check status: ./activemq status

# Test connection: telnet localhost 61616 ```

ActiveMQ Broker Checklist

CheckCommandExpected
Process runningactivemq statusRunning
Memoryfree -mAvailable
LogstailNo errors

Verify the Fix

bash
./activemq status
# Output: ActiveMQ Broker is running
  • [Fix ActiveMQ Slow Consumer](/articles/fix-activemq-slow-consumer)
  • [Fix ActiveMQ Destination Full](/articles/fix-activemq-destination-full)