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How to run rocks on your server

Deploying rocks with Docker

As with any other OCI-compliant container image, rocks can be deployed with your favourite container management tool. This section depicts a typical deployment workflow for a generic Grafana rock, using Docker.

First, install Docker if it’s not already installed:

$ sudo apt-get install -y docker-compose-v2

We can deploy a container with the docker run command. This command has a number of possible parameters. The “Usage” section of the Grafana rock’s documentation has a table with an overview of parameters specific to the image.

$ sudo docker run -d --name grafana-container -e TZ=UTC -p 3000:3000 ubuntu/grafana:10.3.3-22.04_stable
Unable to find image 'ubuntu/grafana:10.3.3-22.04_stable' locally
10.3.3-22.04_stable: Pulling from ubuntu/grafana
bccd10f490ab: Already exists 
549078d9d057: Pull complete 
6ef870aa8500: Pull complete 
2b475da7ccbd: Pull complete 
Digest: sha256:df566ef90ecb14267a459081949ee7b6693fa573b97a7134a9a6722207275caa
Status: Downloaded newer image for ubuntu/grafana:10.3.3-22.04_stable

In this particular case, we’re using:

  • -d to run the container in the background.
  • We are also specifying a well-defined name for the container, with the --name parameter.
  • With -e we are setting the container’s timezone (TZ) environment variable to UTC.
  • We also use -p to map port 3000 of the container to 3000 on localhost.
  • The last parameter indicates the name of the rock, as listed in Docker Hub. Notice that the image tag we requested has the _stable suffix to indicate the image’s risk. This is called a Channel Tag and it follows a similar convention to snap “channels”.

This container, named grafana-container, serves Grafana 10.3.3 in an Ubuntu 22.04 LTS environment and can be accessed via local port 3000. Load the website up in your local web browser:

Welcome to Grafana

If you don’t have Firefox handy, curl can be used instead:

$ curl -s http://localhost:3000/login | grep "<title>"

Now that we’ve tested the deployment of the Grafana rock as a single container, let’s clean it up:

$ sudo docker ps
CONTAINER ID   IMAGE                                COMMAND                  CREATED          STATUS          PORTS                                       NAMES
356e623ef2c1   ubuntu/grafana:10.3.3-22.04_stable   "/bin/pebble enter -…"   17 minutes ago   Up 17 minutes>3000/tcp, :::3000->3000/tcp   grafana-container

We can stop and remove the container as follows:

$ sudo docker stop grafana-container
$ sudo docker rm grafana-container

The Grafana rock’s documentation will also show you how to use Docker’s -v bind mounts to configure Grafana’s provisioning directory and data persistence.

Multi-container deployment

The section above explained the use of a single container for running a single software instance, but one of the benefits of using rocks is the ability to easily create and architecturally organise (or “orchestrate”) them to operate together in a modular fashion.

This section will demonstrate use of docker-compose to set up two container services that inter-operate to implement a trivial observability stack with the Prometheus and Grafana rocks.

Start by creating a Prometheus configuration file called prometheus.yml with the following contents:

  scrape_interval: 1m

  - job_name: 'prometheus'
    scrape_interval: 1m
      - targets: ['localhost:9090']

Note that this is a very simplistic example, where Prometheus only collects metrics about itself. You could expand the above configuration to tell Prometheus to scrape metrics from other sources.

Then, create the Compose file docker-compose.yml and define both services:

    image: ubuntu/grafana:10.3.3-22.04_stable
    container_name: grafana-container
      TZ: UTC
      - "3000:3000"
    image: ubuntu/prometheus:2.49.1-22.04_stable
    container_name: prometheus-container
      TZ: UTC
      - "9090:9090"
      - ./prometheus.yml:/etc/prometheus/prometheus.yml

Note that the Prometheus configuration file is being given to the container via a Docker volume (of type “bind mount”). The above sample could also be improved to also use another volume for persisting data, and even a Grafana default configuration for the Prometheus datasource.

Since we already installed Docker in the section above, all that is needed is to create and start the containers defined in this Compose file. This can be achieved with:

$ sudo docker compose up -d
[+] Running 10/10
 ✔ grafana Pulled                                                                                                                                                                                                                                                                   
   ✔ bccd10f490ab Already exists                                                                                                                                                                                                                                                     
   ✔ 549078d9d057 Pull complete                                                                                                                                                                                                                                                     
   ✔ 6ef870aa8500 Pull complete                                                                                                                                                                                                                                                     
   ✔ 2b475da7ccbd Pull complete                                                                                                                                                                                                                                                     
 ✔ prometheus Pulled                                                                                                                                                                                                                                                                
   ✔ a8b1c5f80c2d Already exists                                                                                                                                                                                                                                                     
   ✔ f021062473aa Pull complete                                                                                                                                                                                                                                                     
   ✔ 9c6122d12d1d Pull complete                                                                                                                                                                                                                                                     
   ✔ 274b56f68abe Pull complete                                                                                                                                                                                                                                                     
[+] Running 3/3
 ✔ Network compose_default         Created                                                                                                                                                                                                                                           
 ✔ Container prometheus-container  Started                                                                                                                                                                                                                                           
 ✔ Container grafana-container     Started 

As before, the -d indicates that all containers in this stack should be started in the background. You can confirm they are live and running with:

$ sudo docker compose ps
NAME                   IMAGE                                   COMMAND                  SERVICE      CREATED         STATUS         PORTS
grafana-container      ubuntu/grafana:10.3.3-22.04_stable      "/bin/pebble enter -…"   grafana      3 seconds ago   Up 3 seconds>3000/tcp, :::3000->3000/tcp
prometheus-container   ubuntu/prometheus:2.49.1-22.04_stable   "/bin/pebble enter -…"   prometheus   3 seconds ago   Up 3 seconds>9090/tcp, :::9090->9090/tcp

Opening http://localhost:3000 will give you the same Grafana login page as before:

Welcome to Grafana

Use the default username admin and password admin to login:

Grafana login

By clicking on “Data Sources” you can then add Prometheus and provide the server URL http://prometheus:9090:

Prometheus data source

This URL works because Docker Compose ensures both containers are on the same Docker network and that they can be discovered via their service name.

Finally, click on “Explore” from the Grafana menu, and select the prometheus datasource. You can now query and visualise the Prometheus metrics. For example:

Prometheus data source

Next Steps

As you can see, docker-compose makes it convenient to set up multi-container applications without needing to perform runtime changes to the containers. As you can imagine, this can permit building a more sophisticated management system to handle fail-over, load-balancing, scaling, upgrading old nodes, and monitoring status. But rather than needing to implement all of this directly on top of docker-container, you may want to investigate Kubernetes-style cluster management software such as microk8s.

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