Build a Swarm cluster

Could you just run docker-compose on your server to keep some containers running?

FWIW, one thing the new Swarm mode stuff includes is support for rolling updates, so that e.g. you could have two containers behind a load balancer and roll out a new image without (or more likely to start, with minimal) downtime. Even on a single host this is useful, but you do still need a little shell glue.

I do agree that the "medium size" (useful to the vast majority of people) documentation resources that are available are quite inadequate today.

I'm in the process of building a system to do just that; super easy, small to medium container deployment. It's still a WIP and there's not much (or any) documentation, but if it generates some interest I'll work on it more and maybe post a Show HN.

In short, all you have to do is POST a url to a github repo and the system will pull your code, build a docker image from your Dockerfile, spin up a container, and then reverse proxy to the container's IP.

All you have to do is provide a repo with a Dockerfile and the deployment system does the rest.

Here's the code for it; https://gitlab.rlyshw.com/rlyshw/tiny-deploy

and here is an outdated blog post that outlines how it works; https://blog.rlyshw.com/2016/07/13/home-brew-deployment-syst...

I have been in a similar place lately. We have a primary rails application with 1 other web service and a DB. We looked at docker machine, docker swarm, and tutum (now a docker hub feature). None were very clear to use. Right now we've settled on Kubernetes and couldn't be happier. It was quite daunting at first as their docs aren't very newcomer friendly, but after a few youtube videos to get the ideas straight, it feels like the perfect way to deploy and orchestrate dockerized applications. You mention using Digital Ocean - you should reach out to Bryan Liles there, who is a super sharp and friendly guy and can help you with Kubernetes on DI. We'll probably be using Google's stuff for our deployments, but with Kubernetes it really doesn't matter anymore. Hope that helps!

You might want to check out minikube.

https://github.com/kubernetes/minikube

Super easy way to get Kubernetes running on a single host.

In my experience Dokku is perfect for this. It uses Heroku's buildpacks to build your app inside a Docker container (or containers) and serves it on yourapp.yourserver.com via a git push: https://github.com/dokku/dokku

I've got ~5 low-traffic websites running on a 1GB Droplet.

I may have what you're looking for: I've been working on exactly this problem, because I grew tired of the headaches from maintaining a "snowflake server" (http://martinfowler.com/bliki/SnowflakeServer.html), which I configured once in the past and would be very difficult to reproduce.

Here's a super-simple Docker host stack I put together that you can install on a cloud machine fairly easily. It runs Docker containers, does automatic backups, and has monitoring and alerting built-in. I've run around 5 webapps, split between 10 containers, on this infrastructure for about 6 months with significantly fewer headaches. Monitoring alerts go straight into a personal Slack channel.

The implementation is deliberately low-level -- you'll be running bare docker commands -- because the goal is to have a trivial infrastructure and to learn Docker in the process. There's no reliance on the "magic" in big wrappers like Kubernetes. Because there's nothing fancy in here, it's simple to understand and use.

My write-up is rough around the edges right now, but eventually this will turn into a simple blog post with an Ansible playbook attached. Here's a rough draft of how to set it up manually: https://github.com/maximz/docker-host/blob/master/public_doc...

There's an nginx reverse proxy fronting the Docker containers. You can do a zero-downtime deploy pretty easily. Happy to answer any questions if they arise.

If you go the docker-machine route, you can do the following.

    brew install docker-machine
    docker-machine create --name myserver ...digital-ocean-options
    eval $(docker-machine env myserver)
    docker ps

that is:

* install docker-machine

* provision a droplet with docker on it (you can also use test.docker.com to use an RC instead of the latest release)

* set your local shell env to point docker to said machine

* use the docker client to interact with said machine

I also use docker-for-mac and a similar process to spin up swarm-mode clusters. You can also ssh into the machine if you need to by `docker-machine ssh myserver`

[0]: https://docs.docker.com/machine/drivers/digital-ocean/

What I use is tinc to create a kind of a private subnet between all my docker hosts and then only listen with internal dockers on internal ips, ufw rules don't apply to docker networks, docker messes with the iptables directly.

I think the main firewall modification to keep in mind with Docker (swarm mode or not) is that if you publish a port with `--publish`, Docker will pretty much always punch a hole through your existing firewall rules for this port. If you don't want this, simply don't use `--publish` (or the equivalent through the Docker API). Container-to-container communication should be done using containers on the same `docker network` (generally, 'overlay' driver) and should not require exposing ports to the host directly.