Next.js app fails to run in PM2 cluster mode within Docker container

[vgulerianb]

I'm encountering an issue running a Next.js application in a Docker container using PM2's cluster mode. While the application runs successfully in fork mode, it fails when attempting to use cluster mode.

Current Behavior

• Application fails to start in cluster mode with PM2 inside Docker
• Works fine in fork mode
• When executing into the container and running pm2 start manually, it works in cluster mode
• Only fails when using pm2-runtime which is required for Docker

Environment

• Next.js version: 14.2.3
• Node.js version: 19
• PM2 for process management
• Docker containerized environment

ecosystem.config.js

module.exports = {
  apps: [
    {
      name: "nextjs",
      cwd: "./",
      script: "node_modules/.bin/next",
      args: "start",
      // instances: "max",
      // exec_mode: "cluster",
      autorestart: true,
      max_memory_restart: "1G",
      env: {
        PORT: 3000,
        NODE_ENV: "production",
        wait_ready: true,
        listen_timeout: 10000,
        NEXT_SKIP_ENV_VALIDATION: true,
        SKIP_ENV_VALIDATION: true,
      },
    },
  ],
};

Dockerfile CMD

CMD ["pm2-runtime", "/ecosystem.config.js", "--no-daemon"]

Error Logs

No such directory exists as the project root: /ecosystem.config.js
2025-02-17T10:28:53: PM2 log: App [nextjs:1] online
2025-02-17T10:28:53: PM2 error: Cancelling versioning data parsing
2025-02-17T10:28:53: PM2 log: App name:nextjs id:2 disconnected
2025-02-17T10:28:53: PM2 log: App [nextjs:2] exited with code [1] via signal [SIGINT]
2025-02-17T10:28:53: PM2 log: App [nextjs:2] starting in -cluster mode-

Steps to Reproduce

1. Build and run the Docker container with the above configuration
2. Enable cluster mode in ecosystem.config.js by uncommenting:

   instances: "max",
   exec_mode: "cluster",

3. Application fails to start in cluster mode

Additional Information

• The application runs successfully in fork mode
• Manual pm2 start inside the container works in cluster mode
• Issue only occurs with pm2-runtime in cluster mode
• Using Next.js 14.2.3 with Node.js 19

Any assistance or guidance would be greatly appreciated.