Pi-hole in a docker container

Docker Pi-hole

Quick Start

Docker-compose example:

version: "3"

# More info at https://github.com/pi-hole/docker-pi-hole/ and https://docs.pi-hole.net/
services:
  pihole:
    container_name: pihole
    image: pihole/pihole:latest
    ports:
      - "53:53/tcp"
      - "53:53/udp"
      - "67:67/udp"
      - "80:80/tcp"
      - "443:443/tcp"
    environment:
      TZ: 'America/Chicago'
      # WEBPASSWORD: 'set a secure password here or it will be random'
    # Volumes store your data between container upgrades
    volumes:
      - './etc-pihole/:/etc/pihole/'
      - './etc-dnsmasq.d/:/etc/dnsmasq.d/'
    dns:
      - 127.0.0.1
      - 1.1.1.1
    # Recommended but not required (DHCP needs NET_ADMIN)
    #   https://github.com/pi-hole/docker-pi-hole#note-on-capabilities
    cap_add:
      - NET_ADMIN
    restart: unless-stopped

Here is an equivalent docker run script.

Upgrade Notices:

Docker Pi-Hole v4.2.2

• ServerIP no longer a required enviroment variable unless you run network ‘host’ mode! Feel free to remove it unless you need it to customize lighttpd
• –cap-add NET_ADMIN no longer required unless using DHCP, leaving in examples for consistency

Docker Pi-Hole v4.1.1+

Starting with the v4.1.1 release your Pi-hole container may encounter issues starting the DNS service unless ran with the following setting:

• --dns=127.0.0.1 --dns=1.1.1.1 The second server can be any DNS IP of your choosing, but the first dns must be 127.0.0.1
  • A WARNING stating “Misconfigured DNS in /etc/resolv.conf” may show in docker logs without this.
• 4.1 required –cap-add NET_ADMIN until 4.2.1-1

These are the raw docker run cli versions of the commands. We provide no official support for docker GUIs but the community forums may be able to help if you do not see a place for these settings. Remember, always consult your manual too!

Overview

Renamed from diginc/pi-hole to pihole/pihole

A Docker project to make a lightweight x86 and ARM container with Pi-hole functionality.

1. Install docker for your x86-64 system or ARMv7 system using those links. Docker-compose is also recommended.
2. Use the above quick start example, customize if desired.
3. Enjoy!

Running Pi-hole Docker

This container uses 2 popular ports, port 53 and port 80, so may conflict with existing applications ports. If you have no other services or docker containers using port 53/80 (if you do, keep reading below for a reverse proxy example), the minimum arguments required to run this container are in the script docker_run.sh

If you’re using a Red Hat based distribution with an SELinux Enforcing policy add :z to line with volumes like so:

    -v "$(pwd)/etc-pihole/:/etc/pihole/:z" \
    -v "$(pwd)/etc-dnsmasq.d/:/etc/dnsmasq.d/:z" \

Volumes are recommended for persisting data across container re-creations for updating images. The IP lookup variables may not work for everyone, please review their values and hard code IP and IPv6 if necessary.

Port 443 is to provide a sinkhole for ads that use SSL. If only port 80 is used, then blocked HTTPS queries will fail to connect to port 443 and may cause long loading times. Rejecting 443 on your firewall can also serve this same purpose. Ubuntu firewall example: sudo ufw reject https

Automatic Ad List Updates - since the 3.0+ release, cron is baked into the container and will grab the newest versions of your lists and flush your logs. Set your TZ environment variable to make sure the midnight log rotation syncs up with your timezone’s midnight.

Running DHCP from Docker Pi-Hole

There are multiple different ways to run DHCP from within your Docker Pi-hole container but it is slightly more advanced and one size does not fit all. DHCP and Docker’s multiple network modes are covered in detail on our docs site: Docker DHCP and Network Modes

Environment Variables

There are other environment variables if you want to customize various things inside the docker container:

To use these env vars in docker run format style them like: -e DNS1=1.1.1.1

Here is a rundown of other arguments for your docker-compose / docker run.

Tips and Tricks

• A good way to test things are working right is by loading this page: http://pi.hole/admin/
• How do I set or reset the Web interface Password?
  • docker exec -it pihole_container_name pihole -a -p - then enter your password into the prompt
• Port conflicts? Stop your server’s existing DNS / Web services.
  • Don’t forget to stop your services from auto-starting again after you reboot
  • Ubuntu users see below for more detailed information
• Port 80 is highly recommended because if you have another site/service using port 80 by default then the ads may not transform into blank ads correctly. To make sure docker-pi-hole plays nicely with an existing webserver you run you’ll probably need a reverse proxy webserver config if you don’t have one already. Pi-hole must be the default web app on the proxy e.g. if you go to your host by IP instead of domain then Pi-hole is served out instead of any other sites hosted by the proxy. This is the ‘default_server’ in nginx or 'default’ virtual host in Apache and is taken advantage of so any undefined ad domain can be directed to your webserver and get a ‘blocked’ response instead of ads.
  • You can still map other ports to Pi-hole port 80 using docker’s port forwarding like this -p 8080:80, but again the ads won’t render properly. Changing the inner port 80 shouldn’t be required unless you run docker host networking mode.
  • Here is an example of running with jwilder/proxy (an nginx auto-configuring docker reverse proxy for docker) on my port 80 with Pi-hole on another port. Pi-hole needs to be DEFAULT_HOST env in jwilder/proxy and you need to set the matching VIRTUAL_HOST for the Pi-hole’s container. Please read jwilder/proxy readme for more info if you have trouble.

Installing on Ubuntu

Modern releases of Ubuntu (17.10+) include systemd-resolved which is configured by default to implement a caching DNS stub resolver. This will prevent pi-hole from listening on port 53. The stub resolver should be disabled with: sudo sed -r -i.orig 's/#?DNSStubListener=yes/DNSStubListener=no/g' /etc/systemd/resolved.conf

This will not change the nameserver settings, which point to the stub resolver thus preventing DNS resolution. Change the /etc/resolv.conf symlink to point to /run/systemd/resolve/resolv.conf, which is automatically updated to follow the system’s netplan: sudo sh -c 'rm /etc/resolv.conf && ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf'

Once pi-hole is installed, you’ll want to configure your clients to use it (see here). If you used the symlink above, your docker host will either use whatever is served by DHCP, or whatever static setting you’ve configured. If you want to explicitly set your docker host’s nameservers you can edit the netplan(s) found at /etc/netplan, then run sudo netplan apply. Example netplan:

network:
    ethernets:
        ens160:
            dhcp4: true
            dhcp4-overrides:
                use-dns: false
            nameservers:
                addresses: [127.0.0.1]
    version: 2

Note that it is also possible to disable systemd-resolved entirely. However, this can cause problems with name resolution in vpns (see bug report). It also disables the functionality of netplan since systemd-resolved is used as the default renderer (see man netplan). If you choose to disable the service, you will need to manually set the nameservers, for example by creating a new /etc/resolv.conf.

Users of older Ubuntu releases (circa 17.04) will need to disable dnsmasq.

Docker tags and versioning

The primary docker tags / versions are explained in the following table. Click here to see the full list of tags (arm tags are here), I also try to tag with the specific version of Pi-hole Core for version archival purposes, the web version that comes with the core releases should be in the GitHub Release notes.

pihole/pihole:latest

This version of the docker aims to be as close to a standard Pi-hole installation by using the recommended base OS and the exact configs and scripts (minimally modified to get them working). This enables fast updating when an update comes from Pi-hole.

https://hub.docker.com/r/pihole/pihole/tags/

Upgrading, Persistence, and Customizations

The standard Pi-hole customization abilities apply to this docker, but with docker twists such as using docker volume mounts to map host stored file configurations over the container defaults. Volumes are also important to persist the configuration in case you have removed the Pi-hole container which is a typical docker upgrade pattern.

Upgrading / Reconfiguring

Do not attempt to upgrade (pihole -up) or reconfigure (pihole -r). New images will be released for upgrades, upgrading by replacing your old container with a fresh upgraded image is the ‘docker way’. Long-living docker containers are not the docker way since they aim to be portable and reproducible, why not re-create them often! Just to prove you can.

0. Read the release notes for both this Docker release and the Pi-hole release
   • This will help you avoid common problems due to any known issues with upgrading or newly required arguments or variables
   • We will try to put common break/fixes at the top of this readme too
1. Download the latest version of the image: docker pull pihole/pihole
2. Throw away your container: docker rm -f pihole
   • Warning When removing your pihole container you may be stuck without DNS until step 3; docker pull before docker rm -f to avoid DNS inturruption OR always have a fallback DNS server configured in DHCP to avoid this problem altogether.
   • If you care about your data (logs/customizations), make sure you have it volume-mapped or it will be deleted in this step.
3. Start your container with the newer base image: docker run <args> pihole/pihole (<args> being your preferred run volumes and env vars)

Why is this style of upgrading good? A couple reasons: Everyone is starting from the same base image which has been tested to known it works. No worrying about upgrading from A to B, B to C, or A to C is required when rolling out updates, it reducing complexity, and simply allows a ‘fresh start’ every time while preserving customizations with volumes. Basically I’m encouraging phoenix server principles for your containers.

To reconfigure Pi-hole you’ll either need to use an existing container environment variables or if there is no a variable for what you need, use the web UI or CLI commands.

Pi-hole features

Here are some relevant wiki pages from Pi-hole’s documentation. The web interface or command line tools can be used to implement changes to pihole.

We install all pihole utilities so the the built in pihole commands will work via docker exec <container> <command> like so:

• docker exec pihole_container_name pihole updateGravity
• docker exec pihole_container_name pihole -w spclient.wg.spotify.com
• docker exec pihole_container_name pihole -wild example.com

Customizations

The webserver and DNS service inside the container can be customized if necessary. Any configuration files you volume mount into /etc/dnsmasq.d/ will be loaded by dnsmasq when the container starts or restarts or if you need to modify the Pi-hole config it is located at /etc/dnsmasq.d/01-pihole.conf. The docker start scripts runs a config test prior to starting so it will tell you about any errors in the docker log.

Similarly for the webserver you can customize configs in /etc/lighttpd

Systemd init script

As long as your docker system service auto starts on boot and you run your container with --restart=unless-stopped your container should always start on boot and restart on crashes. If you prefer to have your docker container run as a systemd service instead, add the file pihole.service to “/etc/systemd/system”; customize whatever your container name is and remove --restart=unless-stopped from your docker run. Then after you have initially created the docker container using the docker run command above, you can control it with “systemctl start pihole” or “systemctl stop pihole” (instead of docker start/docker stop). You can also enable it to auto-start on boot with “systemctl enable pihole” (as opposed to --restart=unless-stopped and making sure docker service auto-starts on boot).

NOTE: After initial run you may need to manually stop the docker container with “docker stop pihole” before the systemctl can start controlling the container.

Note on Capabilities

DNSMasq / FTLDNS expects to have the following capabilities available:

• CAP_NET_BIND_SERVICE: Allows FTLDNS binding to TCP/UDP sockets below 1024 (specifically DNS service on port 53)
• CAP_NET_RAW: use raw and packet sockets (needed for handling DHCPv6 requests, and verifying that an IP is not in use before leasing it)
• CAP_NET_ADMIN: modify routing tables and other network-related operations (in particular inserting an entry in the neighbor table to answer DHCP requests using unicast packets)

This image automatically grants those capabilities, if available, to the FTLDNS process, even when run as non-root.
By default, docker does not include the NET_ADMIN capability for non-privileged containers, and it is recommended to explicitly add it to the container using --cap-add=NET_ADMIN.
However, if DHCP and IPv6 Router Advertisements are not in use, it should be safe to skip it. For the most paranoid, it should even be possible to explicitly drop the NET_RAW capability to prevent FTLDNS from automatically gaining it.

User Feedback

Please report issues on the GitHub project when you suspect something docker related. Pi-hole or general docker questions are best answered on our user forums. Ping me (@diginc) on the forums if it’s a docker container and you’re not sure if it’s docker related.