Description

Running Debian 9.5 in a LXC container. Upgraded docker-ce to 5:18.09.0~3-0~debian-stretch, which pulls containerd.io version 1.2.0-1.

Steps to reproduce the issue:

1. systemctl start containerd

Describe the results you received:

containerd fails to start due to systemd being unable to execute modprobe overlay inside the container (module is already loaded in host kernel). This is triggered by the following line on the systemd unit file: https://github.com/containerd/containerd/blob/master/containerd.service#L7

Describe the results you expected:

Ideally containerd should check if the module is already loaded, and only if not present try to load the module. Or ExecStartPre should invoke a script that does the same, instead of unconditionally invoking modprobe.

Output of containerd --version:

containerd github.com/containerd/containerd 1.2.0-rc.2 d6de12e2f362cb9dc49ad957911996d3de59b338