Homemmm​.s‑ol.nu

interesting experiments with electronics

my self-hosted Virtual Home

In this post I’ll break down the setup of my self-hosted virtual home: https://s-ol.nu.

First a quick overview of what this guide will cover:

  • HTTPS server with multiple subdomains and varying backends
    • traefik reverse-proxy maintains SSL certificates and serves all requests
    • docker-compose manages running sites/microservices
  • a private-public git server
    • access control, management with gitolite
    • klaus web frontend for browsing and cloning public repos
    • fine-grained permissions and SSH public-key access
  • micro ‘CI’ setup rebuilds & redeploys docker images when updates are pushed

UPDATE (2019-10-03): I updated the git hook below to one that supports pushing and building multiple branches based on the docker-compose.yml.

Most of these projects are very well documented so I won’t go into a lot of detail on setting them up.

HTTPS Server

To run multiple subdomains from a single machine, the HTTP requests need to be matched according to the ‘Host’ header. Most HTTP servers have good facilities for doing this, e.g. apache has vhosts, nginx has server directives etc.

In the past I had used apache as my main server, which worked well for static content and PHP apps, but not all applications fit into this scheme too well and configuration is a tad tedious.

With this latest iteration I am using traefik as a “reverse proxy”. This means traefik doesn’t serve anything (not even static content) by itself, it just delegates requests to one of multiple configured services based on a system of rules.

It also handles letsencrypt certificate generation and updates out-of-the-box and can be tightly integrated with docker, so that it automatically reacts to new services being added.

Traefik can be run at system level, but currently I prefer installing the least system-level applications to have my setup as self-contained as possible. Therefore I went with this traefik in docker-compose setup from kilian.io:

version: '3.4'

services:
  traefik:
    image: traefik:1.5-alpine
    restart: always
    ports:
      - 80:80
      - 443:443
    networks:
      - web
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
      - ./traefik.toml:/traefik.toml
      - ./acme.json:/acme.json
    container_name: traefik

networks:
  web:
    external: true

with the small addition of the :ro at the end of the docker socket volume, to prevent attacks on traefik from being able to take over the host docker system (too easily). In the guide you can find more details, including the traefik.toml that I am using almost verbatim.

Hosting Sites

With traefik set up, dockerized services can be added and exposed trivially. For example to start redirectly, a tiny link redirect service, this addition suffices:

redirectly:
  image: local/redirectly:master
  restart: always
  networks:
    - web
  labels:
    - "traefik.frontend.rule=Host:s-ol.nu"
    - "traefik.enable=true"

By setting different subdomains in the frontend-rule section, many different services can be provided.

The image local/redirectly:git in this case is built automatically when a repo is pushed (see below).

note: if a container doesn’t have an EXPOSE directive, or EXPOSEs multiple ports, you will have to add a traefik.port label specifying which port to use.

private/public Git Server

While I still have a lot of code on Github, where collaboration is easy, I prefer to own the infrastructure that I store my private projects on. I also wanted to have a public web index of some of the projects.

The git infrastructure itself is mananged by gitolite, which I really enjoy using.

repo gitolite-admin @all
  RW+ = s-ol
  C   = s-ol

repo public/.*
  R = @all daemon
  option writer-is-owner = 1

repo ... ...
  RW+ = ludopium

In the first block I grant myself full access to all repos, as well as the right to automatically create repos by attempting to push/pull from them.

The second block makes all repos prefixed with public/ readable by anyone in the gitolite system, as well as the git-daemon, which allows cloning via git://.... access (port 9418). The write-is-owner option lets me set the git description field using ssh git@git.s-ol.nu desc.

I chose the public/ prefix because it results in all public repos being stored in one directory together (/var/lib/gitolite/repositories/public), where klaus can easily pick them up.

The klaus web frontend is set up using traefik above like so:

klaus:
  image: hiciu/klaus-dockerfile
  restart: always
  networks:
    - web
  volumes:
    - /var/lib/gitolite/repositories/public:/srv/git:ro
  command: /opt/klaus/venv/bin/uwsgi --wsgi-file /opt/klaus/venv/local/lib/python2.7/site-packages/klaus/contrib/wsgi_autoreload.py --http 0.0.0.0:8080 --processes 1 --threads 2
  environment:
    KLAUS_REPOS_ROOT: /srv/git
    KLAUS_SITE_NAME: git.s-ol.nu
    KAUS_CTAGS_POLICY: tags-and-branches
    KLAUS_USE_SMARTHTTP: y
  labels:
    - "traefik.frontend.rule=Host:git.s-ol.nu"
    - "traefik.enable=true"

I am using the ‘autoreload’ feature and the hiciu/klaus-dockerfile docker image. Setting KLAUS_USE_SMARTHTTP allows cloning repos via HTTP.

In the future I would like to modify klaus a bit, for example by showing the README in the root of a project per default and applying a custom theme.

Micro-CI

The last piece of the puzzle is automatically deploying projects whenever they are pushed. This can be realized using git’s post-receive hooks and is generally pretty well known.

I followed this gitolite guide for storing repo-specific hooks in the gitolite-admin repo. It requires a change in the gitolite rc file (on the server), but after that you can configure deployment processes in the conf like this:

@dockerize = public/redirectly ...
@jekyllify = blog

repo @dockerize
  option hook.post-receive = docker-deploy

# i actually dont have a jekyll blog anymore but its an easy one as well
repo @jekyllify
  option hook.post-receive = jekyll-deploy

The hooks are stored in the same repo under local/hooks/repo-specific. Here is the docker-deploy hook I am using:

#!/bin/bash
set -e

while read oldrev newrev refname
do
  BRANCH="$(git rev-parse --symbolic --abbrev-ref $refname)"

  # Get project name
  PROJECT="$PWD"
  PROJECT="${PROJECT#*/repositories/public/}"
  PROJECT="${PROJECT#*/repositories/}"
  PROJECT="${PROJECT%.git}"
  PROJECT="$(echo "$PROJECT" | tr "/ " "-_")"

  # Paths
  CHECKOUT_DIR=/tmp/git/$PROJECT
  TARGET_DIR=/home/s-ol/aerol
  IMAGE_NAME=local/$PROJECT:$BRANCH

  # this one doesn't require python & yq, but it means the container has to run already...
  # SERVICES=$(docker ps --filter "ancestor=${IMAGE_NAME}" --format '{{.Label "com.docker.compose.service"}}' \
  #             | sort | uniq)

  SERVICES=$(yq -r <"$TARGET_DIR/docker-compose.yml" \
                    ".services | to_entries | map(select(.value.image == \"${IMAGE_NAME}\").key) \
                     | join(\" \")")

  if [ -z "$SERVICES" ]; then
    continue
  fi

  mkdir -p "$CHECKOUT_DIR"
  GIT_WORK_TREE="$CHECKOUT_DIR" git checkout -q -f $newrev
  echo -e "\e[1;32mChecked out '$PROJECT'.\e[00m"

  cd "$CHECKOUT_DIR"
  docker build -t "$IMAGE_NAME" .
  echo -e "\e[1;32mImage '$IMAGE_NAME' built.\e[00m"

  cd "$TARGET_DIR"
  docker-compose up -d $SERVICES
  echo -e "\e[1;32mService(s) '$SERVICES' restarted.\e[00m"
done

It will build a local/$REPO:$BRANCH image whenever you push, then run docker-compose up -d $SERVICES in $TARGET_DIR, where $SERVICES are all the docker-compose services that use the image. If there are none, no image will be built. For this to work it has to parse the docker-compose.yaml file, which means you have to install yq and jq, e.g. on Ubuntu:

sudo apt-get install jq python3-pip
sudo pip install yq

If you would like to avoid that, you can use the commented command for SERVICES= above, which only relies on docker itself, the only problem is that you will have to do the first build manually (or re-tag a dummy image) before the first build, since it can only detect containers that are already running.

That’s basically it! If you have questions or comments i’ll be happy to hear from you on twitter, github or mastodon.