create basic Dockerfile for having an ssh server with rsync

.dockerignore

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+.git

Dockerfile

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+FROM alpine:3.13
+
+RUN apk add --no-cache \
+	openssh-server \
+	rsync

Makefile

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+.PHONY: build
+build:
+	docker build -t registry.0xdad.com/rsync-ssh-server:latest .
+
+.PHONY: deploy
+deploy: build
+	docker push registry.0xdad.com/rsync-ssh-server:latest

entrypoint.sh

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+#!/bin/sh
+set -eu
+
+ssh-keygen -A
+
+/usr/sbin/sshd
+
+while pgrep -f /usr/sbin/sshd; do
+	sleep 5
+done
+
+>&2 echo 'SSHD is no longer running'
+exit 1