Scenario

A container image myapp:logapp continuously writes logs to stdout. Without log rotation configured, Docker's log files grow unbounded, consuming disk space and potentially filling up the filesystem.

Task

Run a container from the myapp:logapp image with the name myapp_container, enable Docker's built-in log rotation, configure the maximum size for individual log files to 10MB, retain maximum up to 3 log files during rotation, and verify the container is running successfully.

Example

Multiple rotated log files, each ≤10MB
/var/lib/docker/containers/<id>/<id>-json.log: 8.5MB
/var/lib/docker/containers/<id>/<id>-json.log.1: 10MB
/var/lib/docker/containers/<id>/<id>-json.log.2: 10MB
...
Docker automatically rotates logs at 10MB threshold

Step 1: Check the image exists

docker images

Verify myapp:logapp image is available.

Step 2: Run container with log rotation enabled

docker run -d --name myapp_container --log-opt max-size=10m --log-opt max-file=3 myapp:logapp

The --log-opt max-size=10m sets maximum size for each log file to 10 megabytes. Docker's json-file logging driver automatically rotates logs when they reach this limit. Rotated files are named <container-id>-json.log.1, .2, etc., and stored in /var/lib/docker/containers/<container-id>/.

Step 3: Verify container is running

docker ps | grep myapp_container

Confirm the container started successfully. Validation will generate logs and verify rotation.