How to SSH agent forward into a docker container

docker-ssh-forward.bash

docker run -rm -t -i -v $(dirname $SSH_AUTH_SOCK) -e SSH_AUTH_SOCK=$SSH_AUTH_SOCK ubuntu /bin/bash

Based on @tomdavies post, i created this Dockerfile which uses the USER statement in order to have an unpriviledged container instead of su-exec:

FROM python:3.11.6-alpine

RUN apk --no-cache add --update \
    socat \
    sudo

RUN addgroup --gid 1001 -S ansible && adduser --uid 1001 -S ansible -G ansible -h /home/ansible
RUN echo 'ansible ALL=(ALL:ALL) NOPASSWD:/usr/local/bin/create-ansible-agent-socket.sh' > /etc/sudoers
RUN echo 'socat UNIX-LISTEN:/home/ansible/.ssh/agent,fork,user=ansible,group=ansible,mode=777 UNIX-CONNECT:/root/.ssh/agent' > /usr/local/bin/create-ansible-agent-socket.sh
RUN chmod +x /usr/local/bin/create-ansible-agent-socket.sh
RUN echo 'sudo /usr/local/bin/create-ansible-agent-socket.sh & SSH_AUTH_SOCK=/home/ansible/.ssh/agent "$@"' > /entrypoint.sh

USER ansible
RUN mkdir -p /home/ansible/.ssh && chown ansible:ansible /home/ansible/.ssh

ENTRYPOINT [/bin/sh, /entrypoint.sh]

you run it then with

docker run -it -u ansible \
    -v "$SSH_AUTH_SOCK":/root/.ssh/agent \
    -e SSH_AUTH_SOCK=/root/.ssh/agent \
    name cmd

@benjertho After struggling for hours with the same problem (works on first shell login but after that fails), I tried a hack and it worked! Sharing here:

• Add an entrypoint line to dockerfile
  ENTRYPOINT ["/ros_entrypoint.sh"]

• In entrypoint script, add the following at the top:

# Dynamically set SSH_AUTH_SOCK if it's available in the mounted /tmp directory
if [ -n "$(find /tmp -type s -name 'agent.*' 2>/dev/null)" ]; then
  export SSH_AUTH_SOCK=$(find /tmp -type s -name 'agent.*' 2>/dev/null)
fi

• Add the following to your compose.yaml:

environment:
    - SSH_AUTH_SOCK=/tmp/ssh-agent
volumes:
    - /tmp:/tmp

Now the ssh auth sock will be set appropriately every time.

run docker -p  222:22 && apt install openssh-server &&  $(edit /etc/ssh/sshdconfig to enable root login)

on your mac of git bash

eval $(ssh-agent -s)
ssh-add 
ssh -A  toDockerContainer