I have a docker container that runs on a Debian instance in the cloud. Everything runs ok, but after approximately one day, container loses connectivity and docker info returns a warning about disabled ipv4 forwarding.

Running sysctl net.ipv4.ip_forward=1 brings the connectivity back.

What can cause resetting this kernel parameter to 0? Docker version is 18.03 CE.

  • did you set permanently in sysctl.conf file? what type of instance? is it a burstable instance? – Walid May 31 '18 at 22:03
  • No, it's not permanently set in sysctl.conf. It's set by a script before starting docker. Is it possible that docker for some reason reloads sysctl.conf? What could trigger such behavior? The instance is started, docker is started and container is started and that's about it, nothing else is running on this instance. And it's not a preemptible instance or anything like that, it's a CI inside the container. – Gregory Golda Jun 1 '18 at 12:17

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