Just a short note on trying to make Docker behave like a grown up piece of software, since it doesn't come with any default log limits nor log rotation by default.

Table of Contents

Reading the documentation justifies the default setup like this:

Docker keeps the json-file logging driver (without log-rotation) as a default to remain backward compatibility with older versions of Docker, and for situations where Docker is used as runtime for Kubernetes.

Not limiting logs mostly affects very verbose containers, or long running ones. In my case it was my zigbee2mqtt container that had grown to consume all available space.

It seems we have two or three options – either using the default log-driver json-file and limiting it, or using the local log-driver which has log rotation & compression built-in. It is also possible to output logs to journald, which also has log rotation & compression built in, but is awkward to use.

Which is the best option? Dump Docker and use Podman instead! The path of least resistance is probably to keep using json-file and limit its size.

  {
      "log-driver": "json-file",
      "log-opts": {
          "max-size": "250m",
          "max-file": "3"
      }
  }

  {
      "log-driver": "local",
      "log-opts": {
          "max-size": "20m"
      }
  }

  sudo journalctl CONTAINER_NAME=webserver

  {
      "log-driver": "journald"
  }