Issues with Docker

I'm trying to use Docker to create the toolchain and I'm getting some errors:

./build-sdk.sh linux-x86_64 armv7
"docker build" requires exactly 1 argument.
See 'docker build --help'.

Usage:  docker build [OPTIONS] PATH | URL | -

Build an image from a Dockerfile

Adding a dot . (the path) at the end of ${container} build -f Dockerfile.linux-builder -t godot-buildroot-builder-linux seems to fix it.

./build-sdk.sh linux-x86_64 armv7
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post http://%2Fvar%2Frun%2Fdocker.sock/v1.24/build?buildargs=%7B%7D&cachefrom=%5B%5D&cgroupparent=&cpuperiod=0&cpuquota=0&cpusetcpus=&cpusetmems=&cpushares=0&dockerfile=Dockerfile.linux-builder&labels=%7B%7D&memory=0&memswap=0&networkmode=default&rm=1&shmsize=0&t=godot-buildroot-builder-linux&target=&ulimits=null&version=1: dial unix /var/run/docker.sock: connect: permission denied

It gives a permissions error which seems to be solved by running the script with sudo.

sudo ./build-sdk.sh linux-x86_64 armv7
[sudo] password for hiulit: 
Sending build context to Docker daemon  168.5MB
Step 1/2 : FROM centos:7
 ---> 8652b9f0cb4c
Step 2/2 : RUN yum -y install yum install centos-release-scl &&     yum -y install devtoolset-9 &&     yum -y install make ncurses-devel which unzip perl cpio rsync fileutils bc bzip2 gzip sed git python file patch wget perl-Thread-Queue perl-Data-Dumper perl-ExtUtils-MakeMaker &&     yum clean all
 ---> Using cache
 ---> 7dc3436498e3
Successfully built 7dc3436498e3
Successfully tagged godot-buildroot-builder-linux:latest
docker: --userns: invalid USER mode.
See 'docker run --help'.

Seems like Docker doesn't like --userns=keep-id.

And I'm stuck here :)