ssh jumpbox with gpg agent and random password

Dockerfile

FROM --platform=linux/arm64 amazonlinux:2
RUN yum install -y openssh-server
RUN useradd -ms /bin/bash jumpuser
RUN mkdir -v /run/sshd
RUN ssh-keygen -A

USER jumpuser
RUN mkdir ~/.gnupg ~/.ssh
RUN echo 'eval `ssh-agent -s` > /dev/null' >> ~/.bashrc
RUN echo 'export SSH_AUTH_SOCK=$HOME/S.gpg-agent.ssh' >> ~/.bashrc

USER root
COPY entrypoint.sh /
ENTRYPOINT [ "/entrypoint.sh" ]

entrypoint.sh

#!/usr/bin/env bash
random_password() {
    echo -n "jumpuser password: " > /dev/stderr
    dd if=/dev/random count=$(($1 * 2)) bs=1 2> /dev/null | base64 | tr -d '/=+' | head -c "$1" | tee /dev/stderr
    echo > /dev/stderr
}

chpasswd <<< "jumpuser:$(random_password 32)"
while sleep 3 ; do 
  /usr/sbin/sshd -D -p 22
done