Zebra with Docker

The foundation maintains a Docker infrastructure for deploying and testing Zebra.

Quick Start

To get Zebra quickly up and running, you can use an off-the-rack image from Docker Hub:

docker run --name zebra zfnd/zebra

If you want to preserve Zebra's state, you can create a Docker volume:

docker volume create zebrad-cache

And mount it before you start the container:

docker run \
  --mount source=zebrad-cache,target=/home/zebra/.cache/zebra \
  --name zebra \
  zfnd/zebra

You can also use docker compose, which we recommend. First get the repo:

git clone --depth 1 --branch v2.2.0 https://github.com/ZcashFoundation/zebra.git
cd zebra

Then run:

docker compose -f docker/docker-compose.yml up

Custom Images

If you want to use your own images with, for example, some opt-in compilation features enabled, add the desired features to the FEATURES variable in the docker/.env file and build the image:

docker build \
  --file docker/Dockerfile \
  --env-file docker/.env \
  --target runtime \
  --tag zebra:local \
  .

All available Cargo features are listed at https://docs.rs/zebrad/latest/zebrad/index.html#zebra-feature-flags.

To configure Zebra, edit the docker/default-zebra-config.toml config file and uncomment the configs mapping in docker/docker-compose.yml so your config takes effect. You can see if your config works as intended by looking at Zebra's logs.

Alternatively, you can configure Zebra by setting the environment variables in the docker/.env file. Note that the config options of this file are limited to the variables already present in the commented out blocks in it and adding new ones will not be effective. Also note that the values of the variables take precedence over the values set in the docker/default-zebra-config.toml config file. The docker/.env file serves as a quick way to override the most commonly used settings for Zebra, whereas the docker/default-zebra-config.toml file provides full config capabilities.

RPC

Zebra's RPC server is disabled by default. To enable it, you need to set its RPC port. You can do that either in the docker/default-zebra-config.toml file or docker/.env file, as described in the two paragraphs above.

When connecting to Zebra's RPC server, your RPC clients need to provide an authentication cookie to the server or you need to turn the authentication off in Zebra's config. By default, the cookie file is stored at /home/zebra/.cache/zebra/.cookie in the container. You can print its contents by running

docker exec zebra cat /home/zebra/.cache/zebra/.cookie

when the zebra container is running. Note that Zebra generates the cookie file only if the RPC server is enabled, and each Zebra instance generates a unique one. To turn the authentication off, either set ENABLE_COOKIE_AUTH=false in docker/.env or set

[rpc]
enable_cookie_auth = false

in docker/default-zebra-config.toml and mount this config file into the container's filesystem in docker/docker-compose.yml as described at the beginning of this section.

Examples

To make the initial setup of Zebra with other services easier, we provide some example files for docker compose. The following subsections will walk you through those examples.

Running Zebra with Lightwalletd

The following command will run Zebra with Lightwalletd:

docker compose -f docker/docker-compose.lwd.yml up

Note that Docker will run Zebra with the RPC server enabled and the cookie authentication mechanism disabled since Lightwalletd doesn't support it. Instead of configuring Zebra via the recommended config file or docker/.env file, we configured the RPC server by setting environment variables directly in the docker/docker-compose.lwd.yml file. This is a shortcut we can take when we are familiar with the docker/.env file.

Running Zebra with Prometheus and Grafana

The following commands will run Zebra with Prometheus and Grafana:

docker compose -f docker/docker-compose.grafana.yml build --no-cache
docker compose -f docker/docker-compose.grafana.yml up

In this example, we build a local Zebra image with the prometheus Cargo compilation feature. Note that we enable this feature by specifying its name in the build arguments. Having this Cargo feature specified at build time makes cargo compile Zebra with the metrics support for Prometheus enabled. Note that we also specify this feature as an environment variable at run time. Having this feature specified at run time makes Docker's entrypoint script configure Zebra to open a scraping endpoint on localhost:9999 for Prometheus.

Once all services are up, the Grafana web UI should be available at localhost:3000, the Prometheus web UI should be at localhost:9090, and Zebra's scraping page should be at localhost:9999. The default login and password for Grafana are both admin. To make Grafana use Prometheus, you need to add Prometheus as a data source with the URL http://localhost:9090 in Grafana's UI. You can then import various Grafana dashboards from the grafana directory in the Zebra repo.

Running CI Tests Locally

To run CI tests locally, first set the variables in the test.env file to configure the tests, then run:

docker-compose -f docker/docker-compose.test.yml up

The Zebra Book