add basic rsync server image

.dockerignore

@@ -0,0 +1 @@
+.git

Dockerfile

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+FROM alpine:3.13
+
+RUN apk add --no-cache \
+	openssh-server \
+	rsync
+
+RUN mkdir -p /root/.ssh && cp /etc/ssh/sshd_config /etc/default_sshd_config

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

README.md

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 # docker-rsync-server
 
+This is a simple docker image definition for starting an SSH server that is used for rsyncing to volume mounts.
+
+## Volumes
+
+| path                       | description                           |
+|----------------------------|---------------------------------------|
+| /root/.ssh/authorized_keys | the ssh keys to allow for auth        |
+| /etc/ssh                   | location for SSH host keys and config |
+| anywhere else              | the locations available for rsync     |

entrypoint.sh

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+#!/bin/sh
+set -eu
+
+ssh-keygen -A
+
+if [ ! -e '/etc/ssh/sshd_config' ]; then
+	cp /etc/default_sshd_config /etc/ssh/sshd_config
+fi
+
+/usr/sbin/sshd
+
+while pgrep -f /usr/sbin/sshd; do
+	sleep 5
+done
+
+>&2 echo 'SSHD is no longer running'
+exit 1