Cannot use `sudo` on aarch64

[martin-g]

Hi!

Thank you for this project! It is really helpful!

I've found an issue that prevents me to use Alpine Linux abuild tool on it.
abuild has to be executed by a non-root user with sudo but fails with Cannot lock database error while trying to install the dependencies with apk add.

I was able to minimize the problem to these steps:

1. docker run -it --rm multiarch/alpine:aarch64-edge sh
2. apk add sudo
3. adduser xyz
4. echo "xyz ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers
5. su xyz
6. sudo ls -la

sudo: effective uid is not 0, is /usr/bin/sudo on a file system with the 'nosuid' option set or an NFS file system without root privileges?

If I replace multiarch/alpine:aarch64-edge with alpine:3 at step 1 then everything is OK.

It looks similar to these issues:

1. Cannot use sudo command inside Nvidia-Docker image moby/moby#36730 (comment)
2. nosuid problem in foreign architecture builds alpinelinux/docker-abuild#47

Any idea how to work it around ?

[martin-g]

I've just found a workaround!
multiarch/qemu-user-static#17 (comment)

docker run --rm --privileged multiarch/qemu-user-static:register --reset --credential yes

--credential yes is the key.

It would be nice to mention this in the README. Thank you!