Dockerfile.alpine

FROM alpine:3.16.0

# Use an older Alpine base so core packages remain behind the current v3.16
# repositories and `apk list -u` reports pending updates.
RUN apk add --no-cache \
        openssh-server sudo bash \
        curl wget vim git nano \
        htop tree zip unzip jq && \
    mkdir -p /run/sshd

# Configure SSH
RUN sed -i 's/^#PasswordAuthentication yes/PasswordAuthentication yes/' /etc/ssh/sshd_config && \
    sed -i 's/^#PermitRootLogin prohibit-password/PermitRootLogin no/' /etc/ssh/sshd_config && \
    echo 'PasswordAuthentication yes' >> /etc/ssh/sshd_config

# Create test user with sudo
RUN adduser -D -s /bin/bash testuser && \
    echo 'testuser:testpass' | chpasswd && \
    echo 'testuser ALL=(ALL) NOPASSWD:ALL' > /etc/sudoers.d/testuser && \
    chmod 440 /etc/sudoers.d/testuser

# Fail the build early if sudo is not usable for the test user.
RUN su - testuser -c "sudo -n true"

# Generate host keys
RUN ssh-keygen -A

EXPOSE 22
CMD ["/usr/sbin/sshd", "-D"]