1. Set up the environment¶

This is a part of the Charmed Apache Cassandra Tutorial.

For this tutorial, we need to set up the environment with two main components, plus some extra command-line tooling:

LXD - a system container and virtual machine manager that provides the local cloud our cluster runs on
Juju - lets us deploy and manage Charmed Apache Cassandra and related applications
jq - a command-line JSON processor used to parse command output

Prepare the cloud¶

The fastest, simplest way to get started with Charmed Apache Cassandra is to set up a local LXD cloud. Each Cassandra node runs inside an LXD container managed by Juju. While this tutorial covers the basics of LXD, you can learn more about LXD here.

LXD comes pre-installed on Ubuntu 24.04 LTS. Verify that LXD is installed by entering the command which lxd. This will output /snap/bin/lxd or, on some systems, /usr/sbin/lxd.

Although LXD is already installed, we need to run lxd init to perform post-installation tasks. For this tutorial the default parameters are preferred, and the network bridge should be set to have no IPv6 addresses since Juju does not support IPv6 addresses with LXD:

lxd init --auto
lxc network set lxdbr0 ipv6.address none

You can list all LXD containers by entering the command lxc list. At this point of the tutorial none should exist, so you will only see this output:

+------+-------+------+------+------+-----------+
| NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS |
+------+-------+------+------+------+-----------+

Install and prepare Juju¶

Juju is an Operator Lifecycle Manager (OLM) for clouds, bare metal, LXD and Kubernetes. We will use it to deploy and manage Charmed Apache Cassandra. As with LXD, Juju is installed from a snap package:

sudo snap install juju --channel 3.6/stable

Install jq, a JSON processor used to parse Juju output in later steps:

sudo snap install jq

Bootstrap a Juju controller¶

Juju already has built-in knowledge of LXD and how it works, so there is no additional cloud setup needed. A Juju controller will be created, which will in turn manage the operations of Charmed Apache Cassandra.

All we need to do is bootstrap a Juju controller named overlord onto the localhost (LXD) cloud. This bootstrapping process can take several minutes depending on the resources available on your machine:

juju bootstrap localhost overlord

The Juju controller runs inside its own LXD container. To verify this, check the list of containers:

lxc list

Output example

+---------------+---------+-----------------------+------+-----------+-----------+
|     NAME      |  STATE  |         IPV4          | IPV6 |   TYPE    | SNAPSHOTS |
+---------------+---------+-----------------------+------+-----------+-----------+
| juju-<id>     | RUNNING | 10.166.144.1 (eth0)   |      | CONTAINER | 0         |
+---------------+---------+-----------------------+------+-----------+-----------+

where <id> is a unique combination of numbers and letters such as 9d7e4e-0.

Create a model¶

A controller can manage multiple models. A model hosts applications such as Charmed Apache Cassandra. Create a model named tutorial:

juju add-model tutorial

Check the status of the model you just created:

juju status

Output example

Model     Controller  Cloud/Region         Version  SLA          Timestamp
tutorial  overlord    localhost/localhost  3.6.29   unsupported  12:10:54Z

Model "admin/tutorial" is empty.

With the environment ready, we can move on to deploying Charmed Apache Cassandra.