Using Docker

Using Docker

Introduction

With Docker you can easily set up btcd to run your Bitcoin full node. You can find the official btcd Docker images on Docker Hub btcsuite/btcd. The Docker source file of this image is located at Dockerfile.

This documentation focuses on running Docker container with docker-compose.yml files. These files are better to read and you can use them as a template for your own use. For more information about Docker and Docker compose visit the official Docker documentation.

Docker volumes

Special diskspace hint: The following examples are using a Docker managed volume. The volume is named btcd-data This will use a lot of disk space, because it contains the full Bitcoin blockchain. Please make yourself familiar with Docker volumes.

The btcd-data volume will be reused, if you upgrade your docker-compose.yml file. Keep in mind, that it is not automatically removed by Docker, if you delete the btcd container. If you don't need the volume anymore, please delete it manually with the command:

docker volume ls
docker volume rm btcd-data

For binding a local folder to your btcd container please read the Docker documentation. The preferred way is to use a Docker managed volume.

Known error messages when starting the btcd container

We pass all needed arguments to btcd as command line parameters in our docker-compose.yml file. It doesn't make sense to create a btcd.conf file. This would make things too complicated. Anyhow btcd will complain with following log messages when starting. These messages can be ignored:

Error creating a default config file: open /sample-btcd.conf: no such file or directory
...
[WRN] BTCD: open /root/.btcd/btcd.conf: no such file or directory

Examples

Preamble

All following examples uses some defaults:

container_name: btcd Name of the docker container that is be shown by e.g. docker ps -a
hostname: btcd (very important to set a fixed name before first start) The internal hostname in the docker container. By default, docker is recreating the hostname every time you change the docker-compose.yml file. The default hostnames look like ef00548d4fa5. This is a problem when using the btcd RPC port. The RPC port is using a certificate to validate the hostname. If the hostname changes you need to recreate the certificate. To avoid this, you should set a fixed hostname before the first start. This ensures, that the docker volume is created with a certificate with this hostname.
restart: unless-stopped Starts the btcd container when Docker starts, except that when the container is stopped (manually or otherwise), it is not restarted even after Docker restarts.

To use the following examples create an empty directory. In this directory create a file named docker-compose.yml, copy and paste the example into the docker-compose.yml file and run it.

mkdir ~/btcd-docker
cd ~/btcd-docker
touch docker-compose.yaml
nano docker-compose.yaml (use your favourite editor to edit the compose file)
docker-compose up (creates and starts a new btcd container)

With the following commands you can control docker-compose:

docker-compose up -d (creates and starts the container in background)

docker-compose down (stops and delete the container. The docker volume btcd-data will not be deleted)

docker-compose stop (stops the container)

docker-compose start (starts the container)

docker ps -a (list all running and stopped container)

docker volume ls (lists all docker volumes)

docker logs btcd (shows the log )

docker-compose help (brings up some helpful information)

Full node without RPC port

Let's start with an easy example. If you just want to create a full node without the need of using the RPC port, you can use the following example. This example will launch btcd and exposes only the default p2p port 8333 to the outside world:

version: "2"

services:
  btcd:
    container_name: btcd
    hostname: btcd
    image: btcsuite/btcd:latest
    restart: unless-stopped
    volumes:
      - btcd-data:/root/.btcd
    ports:
      - 8333:8333

volumes:
  btcd-data:

Full node with RPC port

To use the RPC port of btcd you need to specify a username and a very strong password. If you want to connect to the RPC port from the internet, you need to expose port 8334(RPC) as well.

version: "2"

services:
  btcd:
    container_name: btcd
    hostname: btcd
    image: btcsuite/btcd:latest
    restart: unless-stopped
    volumes:
      - btcd-data:/root/.btcd
    ports:
      - 8333:8333
      - 8334:8334
    command: [
        "--rpcuser=[CHOOSE_A_USERNAME]",
        "--rpcpass=[CREATE_A_VERY_HARD_PASSWORD]"
    ]

volumes:
  btcd-data:

Full node with RPC port running on TESTNET

To run a node on testnet, you need to provide the --testnet argument. The ports for testnet are 18333 (p2p) and 18334 (RPC):

version: "2"

services:
  btcd:
    container_name: btcd
    hostname: btcd
    image: btcsuite/btcd:latest
    restart: unless-stopped
    volumes:
      - btcd-data:/root/.btcd
    ports:
      - 18333:18333
      - 18334:18334
    command: [
        "--testnet",
        "--rpcuser=[CHOOSE_A_USERNAME]",
        "--rpcpass=[CREATE_A_VERY_HARD_PASSWORD]"
    ]

volumes:
  btcd-data:

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