If your Node.js services run under PM2 inside Docker Compose, you already value stability and zero-downtime restarts. But reliability doesn\u2019t happen by accident. Clear logs, actionable monitoring, and trustworthy health checks are the guardrails that keep production calm. In this guide, you will learn pragmatic ways to wire PM2 with Docker Compose so your services are observable, self-healing, and ready for scale.<\/p>\n
Logs tell you what happened. Monitoring tells you what is happening now. Health checks tell Docker when to step in and restart something that can\u2019t heal itself. Together, they reduce mean time to detection (MTTD) and mean time to recovery (MTTR), directly influencing uptime and customer trust.<\/p>\n
Inside containers, the rules change slightly: you want processes to write to stdout\/stderr<\/em>, you lean on the platform for rotation and shipping, and you codify liveness\/readiness. PM2 adds process supervision and clustering on top, but you need to configure it the \u201ccontainer-native\u201d way.<\/p>\n PM2 can manage one or many Node.js processes. In containers, the recommended entrypoint is pm2-runtime<\/strong>, which behaves well as PID 1 and relays logs to the container\u2019s stdout\/stderr.<\/p>\n Ensure your app listens to SIGINT\/SIGTERM and closes servers and DB connections. PM2 will forward signals so Docker can stop quickly during deploys.<\/p>\n For CPU-bound workloads or parallel I\/O, PM2\u2019s cluster mode (instances: “max”<\/em> or a number) balances workers behind a single port. Make sure readiness checks reflect readiness<\/em> of the whole service, not just one worker.<\/p>\n In containers, write logs to stdout\/stderr. PM2 does this by default with pm2-runtime<\/em>. This lets Docker\u2019s logging driver collect, rotate, and ship logs without extra agents in the container.<\/p>\n If you rely on the default json-file<\/em> driver, configure rotation in Compose so logs don\u2019t fill disks:<\/p>\n This rotates container logs automatically without changing PM2.<\/p>\n If you intentionally write to files (e.g., persistent audit logs), use pm2 install pm2-logrotate<\/em> and configure rotation limits. Keep in mind that file-based logs inside containers are an anti-pattern unless mounted to a volume and shipped externally.<\/p>\n Key lines you might put under a service in docker-compose.yml:<\/p>\n In ecosystem.config.js<\/em>, consider:<\/p>\n Compose snippet lines for an HTTP health endpoint at \/health<\/em>:<\/p>\n Production systems benefit from external log aggregation for search, dashboards, and alerts.<\/p>\n Example lines for a GELF driver:<\/p>\n Pick one<\/em> path to aggregation to avoid paying twice in egress and storage. Either ship from Docker or from a sidecar agent, not both.<\/p>\nHow PM2 Fits Inside Containers<\/h2>\n
pm2 vs pm2-runtime<\/h3>\n
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Graceful shutdown<\/h3>\n
Clustering<\/h3>\n
Logging Strategies for PM2 in Docker Compose<\/h2>\n
1) Prefer stdout\/stderr over files<\/h3>\n
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2) Format and enrich logs with environment<\/h3>\n
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3) Control size with Docker log options<\/h3>\n
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4) PM2 Logrotate (when you write files)<\/h3>\n
5) Persist logs sparingly<\/h3>\n
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Docker Compose Examples and Patterns<\/h2>\n
Service with pm2-runtime and JSON logs<\/h3>\n
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PM2 ecosystem essentials<\/h3>\n
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Healthcheck with HTTP<\/h3>\n
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Centralized Logging Options<\/h2>\n
Use Docker logging drivers<\/h3>\n
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Don\u2019t duplicate<\/h3>\n
Monitoring Options for PM2 Apps<\/h2>\n
PM2 built-ins<\/h3>\n