Dockerfile

FROM alpine:latest

RUN apk add --no-cache openssh-client

COPY ./entrypoint.sh /bin/

ENTRYPOINT [ "/bin/entrypoint.sh" ]

entrypoint.sh

#!/bin/sh

if [ -d /root/.ssh ]; then
  chmod -R 600 /root/.ssh
fi

if [ -z "$SSH_PORT" ]; then
  SSH_PORT=22
fi

if [ -z "$REMOTE_IP" ]; then
  REMOTE_IP=*
fi

echo "$(date +"%Y-%m-%d %H:%m:%S%z") [INFO] opening tunnel at ${SSH_LOGIN} (port ${SSH_PORT})"

while true; do
	# bind logstash at localhost:5044 of remote host
	ssh -N \
	-o UserKnownHostsFile=/dev/null \
	-o StrictHostKeyChecking=no \
	-o ExitOnForwardFailure=yes \
	-o ServerAliveInterval=500 \
	-o ServerAliveCountMax=3 \
	-R ${REMOTE_IP}:${REMOTE_PORT}:${CONTAINER_HOST}:${CONTAINER_PORT} \
	-p ${SSH_PORT} ${SSH_LOGIN};

	echo "$(date +"%Y-%m-%d %H:%m:%S%z") [INFO] connection closed. reconnecting in 3 seconds.."

	sleep 3;
done