Many DevOps engineers face a common challenge when trying to modify logging configurations for running Docker containers. Unlike other container properties that can be updated dynamically, the logging driver is immutable after container creation. This behavior stems from Docker's architectural design where logging drivers are initialized during container startup.

As confirmed in Docker's logging documentation:

Important: The logging driver for a container cannot be changed after the container is created.

While direct modification isn't possible, here are effective alternatives:

1. Container Recreation with Log Preservation

For stateless applications:

# Stop and commit the existing container
docker stop my_container
docker commit my_container my_image:temp

# Create new container with desired logging driver
docker run -d --log-driver=syslog --log-opt syslog-address=tcp://1.2.3.4:514 \
    --name my_new_container my_image:temp

2. Using Docker Logging Plugins

For mission-critical containers:

# Configure syslog logging plugin
docker plugin install --alias syslog \
    grafana/loki-docker-driver:latest \
    --grant-all-permissions

Here's a complete workflow for a web application container:

# Step 1: Capture current configuration
docker inspect -f '{{.HostConfig.LogConfig.Type}}' my_webapp

# Step 2: Create new container with syslog
docker run -d \
    --log-driver=syslog \
    --log-opt syslog-address=udp://logs.example.com:514 \
    --log-opt tag="{{.Name}}" \
    --name webapp_v2 \
    -p 8080:80 \
    my_webapp_image:latest

# Step 3: Verify new logging configuration
docker inspect -f '{{.HostConfig.LogConfig}}' webapp_v2

• Always test new logging configurations in staging first
• Consider log rotation settings for json-file driver if recreation isn't immediate
• For Kubernetes environments, configure logging at the cluster level

The Docker community is actively discussing runtime logging driver changes in GitHub Issue #40365. Monitor this ticket for potential future solutions.

While Docker allows configuring default logging drivers at the daemon level (/etc/docker/daemon.json), changing the logging driver for existing running containers remains problematic. The json-file driver persists logs to disk, while syslog forwards them directly to system logging facilities - a crucial difference for production environments.

The official docker update command doesn't support logging driver modifications. Editing config.v2.json directly (typically found at /var/lib/docker/containers/[container-id]/config.v2.json) appears ineffective because Docker's runtime configuration takes precedence over static files.

Here's a production-tested approach using Docker's commit/export functionality:

# Step 1: Commit the running container to an image
docker commit [container-name] temp-image

# Step 2: Stop and remove the original container
docker stop [container-name] && docker rm [container-name]

# Step 3: Recreate with new logging driver
docker run -d --log-driver=syslog --name [new-container-name] temp-image

For automated environments, you can script this through Docker's API:

import docker
client = docker.from_env()

container = client.containers.get('original-container')
container.commit('temp-image')
container.stop()
container.remove()

new_container = client.containers.run(
    'temp-image',
    log_config={'type': 'syslog'},
    detach=True,
    name='new-container'
)

• Any volumes will need reattachment
• Network ports will need reconfiguration
• Runtime state will be lost unless explicitly preserved

For critical production systems, consider:

1. Implement log forwarding at the application level
2. Use sidecar containers for log aggregation
3. Standardize on a logging driver during initial deployment