docker-router

docker-router

Routing proxy for Docker containers with native LetsEncrypt support

Overview

Docker router project is designed for a specific purpose - to route and load balance HTTP traffic across docker containers, with automatic LetsEncrypt support. It's also intended to be as much config-less as possible. While there are many other docker-based load balancers/routers on the market (traefik, fabio, nginx-gen, etc) docker-router aims to be extremely simple with a limited number of features.

Single host use only

Docker router is intended to be used on a single machine, so if you're planning on load balancing traffic to containers located on different machines you might need to consider other solutions (traefik/fabio).

No centralized store

Dynamic routes are pulled off docker configuration, meaning docker-router will inspect all existing (running) containers and detemine which ones should be live. All internal configuration state is stored in memory only and will be rebuilt during service restarts.

Automatic SSL with LetsEncrypt

Original goal of the project was to automatically enable SSL termination via LetsEncrypt certificate management and remove the need to manage that part manually or via other dependencies like certbot.

Simple Configuration

Docker router does not support reading configuration from a file and all configuration must be done via environment variables (for host) and docker labels (for containers). To make a container discoverable add the following labels when starting it:

docker run \
  --label router.domain=myapp.com
  myapp

Usage

Start the proxy container:

docker run \
  -d \
  --name=router \
  --restart=always \
  -p 80:80 \
  -p 443:443 \
  --net=app \
  -e HTTP_PORT=80 \
  -e HTTPS_PORT=443 \
  -e DOCKER_NETWORK=app \
  -e LETSENCRYPT_EMAIL=...YOUR EMAIL... \
  -e LETSENCRYPT_CERTS_DIR=/certs \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -v /root/certs:/certs \
  sosedoff/docker-router

To route HTTP requests to your containers, start them with options:

docker run \
  --name=myapp \
  --restart=always \
  -d \
  -e PORT=5000 \
  --label=router.domain=myawesomeapp.com \
  --label=router.healthcheck=/heartbeat \
  --net=app \
  myapp

Debugging

To see the internal routing state and table, add DEBUG=1 env var when starting docker-proxy.

You should be able to open http://router-hostname/_debug_/info endpoint.

Example:

{
  "accesstime": {
    "06bf3fd503ca419f18e4d175d5143fcadc79389f918288f995d785da2320bb8b": "2019-04-26T16:48:38.12782292Z",
    "41a2b6cfaf5822d743a6ae0a178d1b3cd32e5534d274310e75eb21fc68eaa5e4": "2019-04-26T16:57:06.655900487Z",
    "518a0dc6ca67837954f08c20ad2dec48904b508728d456eeeba7bafab8f88cab": "2019-04-26T16:57:06.958181838Z"
  },
  "mapping": {
    "41a2b6cfaf5822d743a6ae0a178d1b3cd32e5534d274310e75eb21fc68eaa5e4": "myawesomeapp.com@*",
    "518a0dc6ca67837954f08c20ad2dec48904b508728d456eeeba7bafab8f88cab": "myawesomeapp.com@*",
    "751d7b4a32a02cd56d8f1009d490e2d3b13d62da3b2a90ea609563e63ea69398": "myawesomeapp.com@*"
  },
  "routes": {
    "myawesomeapp.com": {
      "*": {
        "targets": [
          {
            "id": "751d7b4a32a02cd56d8f1009d490e2d3b13d62da3b2a90ea609563e63ea69398",
            "endpoint": "172.20.0.3:5000",
            "count": 0,
            "conns": 0
          },
          {
            "id": "41a2b6cfaf5822d743a6ae0a178d1b3cd32e5534d274310e75eb21fc68eaa5e4",
            "endpoint": "172.20.0.4:5000",
            "count": 0,
            "conns": 0
          },
          {
            "id": "518a0dc6ca67837954f08c20ad2dec48904b508728d456eeeba7bafab8f88cab",
            "endpoint": "172.20.0.5:5000",
            "count": 0,
            "conns": 0
          }
        ],
        "total": 24
      }
    }
  }
}

You can also inspect container logs without typing any terminal commands. Visit http://router-hostname/_debug/logs and the page will print out last 1K lines of container logs if there are any.

Features

Basic Authentication

To enable basic authentication, add the following labels with starting docker containers:

docker run \
  ...
  --label auth.user=myuser \
  --label auth.password=mypass \
  ...
  myimages

Password protection will be enabled for all targets within a route. Both username and password labels must be correct otherwise the password authentication is going to be skipped.

Prefix-based Routing

Instead of running different application/containers via subdomains you can use a built-in prefix routing. For example, you might want to add a supplimental pgweb database container and instead of running it on pgweb.myapp.com you can use a special path myapp.com/_pgweb. Another great example is to run multiple versions of API service on the same domain like myapp.com/api/v1 alongside `myapp.com/api/v2'.

To enable to prefix routing, add the following label to docker container:

docker run \
  --label router.domain=myapp.com \
  --label router.prefix=/api/v1 \ # <-- matching over /api/v1 prefix
  myapp

You can disable prefix-based routing by setting an PREFIX_ROUTING=0 environment variable.

Healthchecks

By default docker-router will add the container to the internal routing map as soon as it detects it's start. The new target will be available for routing immediately which could result in clients getting 502 bad gateway error. Usually it takes a few seconds for the application to be fully available before servicing any requests, and to address that docker-router provides a healthcheck feature. To enable it, add the following label to your containers when you start them:

docker run \
  --label router.domain=myapp.com \
  --label router.healthcheck=/health \
  myapp

Websocket Support

Available out of the box with no additional configuration required.

Idle/Wakeup

If you'd like to put containers to sleep after certain idle time, add the following label to your container:

docker run \
  .... 
  --label=router.domain=myawesomeapp.com \
  --label=router.idletime=30m \
  ...

Certificate Store

To store certificate files on the host machine use the LETSENCRYPT_CERTS_DIR environment variable.

To store certificates using Amazon S3 store you'll need to define the following environment variables:

• LETSENCRYPT_S3_BUCKET - Bucket name.
• LETSENCRYPT_S3_REGION - Region name. It's important to get this value right.
• AWS_ACCESS_KEY_ID - Optional access key var. Required if not using AWS instance profiles.
• AWS_SECRET_ACCESS_KEY - Optional secret key. Required if not using AWS instance profiles.
• AWS_PROFILE - Optional profile name if ~/.aws/credentials is configured.

OAuth

To enable OAuth flow create a config file with the following contents:

{
  "oauth": {
    "myapp": {
      "provider": "google",
      "client_id": "... paste client id ...",
      "client_secret": "... paste client secret",
      "allowed_domains": [
        "myapp.com"
      ]
    }
  }
}

Then start your container with the label:

docker run \
  ....
  --label=router.domain=myapp.com
  --label=router.oauth=myapp
  ....