Oops! Storage running out in docker swarm cluster nodes…

If you are running your Docker containers in docker swarm and have observed that you are gradually running out of disk space.

There is a simple explanation for this.

Whenever a docker container is running, there are logs files being generated and stored within the container. After a while, the container blows up in size.

In order to prevent this, you can update your Stack service with a small change like below.

logging:
  driver: json-file
    options:
      max-size: "1m"
      max-file: "5"

What this basically enforces, is to have a maximum size of 1 megabyte and a maximum of 5 files to keep. Of course, you can change these values to your needs.

A full example of how to use this is seen below.

version: "3"
services:
  apache:
    image: httpd:2.4
    logging:
      driver: json-file
      options:
        max-size: "1m"
        max-file: "5"
    deploy:
      resources:
        limits:
          cpus: "0.50"
          memory: "512M"
        reservations:
          cpus: "0.25"
          memory: "256M"