Environment Setup

This is part of the Charmed MongoDB Tutorial. Please refer to this page for more information and the overview of the content.

Minimum requirements

Before we start, make sure your machine meets the following requirements:

• Ubuntu 20.04 (Focal) or later.
• 8GB of RAM.
• 2 CPU threads.
• At least 20GB of available storage.
• Access to the internet for downloading the required snaps and charms.

Prepare LXD

The fastest, simplest way to get started with Charmed MongoDB is to set up a local LXD cloud. LXD is a system container and virtual machine manager; Charmed MongoDB will be run in one of these containers and managed by Juju. While this tutorial covers the basics of LXD, you can explore more LXD here. LXD comes pre-installed on Ubuntu 20.04. Verify that LXD is installed by entering the command which lxd into the command line, this will output:

/snap/bin/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 in to the command line. Although at this point in the tutorial none should exist and you’ll only see this as output:

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

Install and prepare Juju

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

sudo snap install juju --classic

Juju already has a built-in knowledge of LXD and how it works, so there is no additional setup or configuration needed. A controller will be used to deploy and control Charmed MongoDB. All we need to do is run the following command to bootstrap a Juju controller named ‘overlord’ to LXD. This bootstrapping processes can take several minutes depending on how provisioned (RAM, CPU, etc.) your machine is:

juju bootstrap localhost overlord

The Juju controller should exist within an LXD container. You can verify this by entering the command lxc list and you should see the following:

+---------------+---------+-----------------------+------+-----------+-----------+
|     NAME      |  STATE  |         IPV4          | IPV6 |   TYPE    | SNAPSHOTS |
+---------------+---------+-----------------------+------+-----------+-----------+
| juju-<id>     | RUNNING | 10.105.164.235 (eth0) |      | CONTAINER | 0         |
+---------------+---------+-----------------------+------+-----------+-----------+

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

The controller can work with different models; models host applications such as Charmed MongoDB. Set up a specific model for Charmed MongoDB named ‘tutorial’:

juju add-model tutorial

You can now view the model you created above by entering the command juju status into the command line. You should see the following:

Model    Controller  Cloud/Region         Version  SLA          Timestamp
tutorial overlord    localhost/localhost  2.9.37   unsupported  23:20:53Z

Model "admin/tutorial" is empty.