[SOLVED] Run docker build inside LXC

[oliwel]

Hi All,

I want to use a LXC container to build docker images - "it doesnt work"....

cat > Dockerfile <<EOF
FROM ubuntu:bionic
RUN apt-get update
EOF
docker build .

It starts to download the files but then I get

Fetched 18.2 MB in 4s (5176 kB/s)
Reading package lists...
Error processing tar file(exit status 1): operation not permitted

The container uses CentOS7, SELinux is turned off (obviously) and the server has the nested, keyctl and fuse capability.

Any ideas?

Oliver

 

[Stefan_R]

Is the 'overlay' module loaded on the host? It needs to be active in the kernel, but can't be loaded from the container for obvious security reasons.

Alternatively, you can set up docker to use the 'vfs' storage driver, but expect poor performance (see https://docs.docker.com/storage/storagedriver/select-storage-driver/ for more)

 

[oliwel]

Hi Stefan,

[root@wrs-centos-build ~]# lsmod | grep overlay overlay 77824 0

So yes it is, but this was the right pointer but not the solution

There are two versions overlay and overlay2 and the docker inside the container uses "Storage Driver: overlay2" which is not found - changing the storage driver to "overlay" (/etc/sysconfig/docker-storage) did the trick.

Oli