Charmed PostgreSQL How-To | Deploy on MAAS

taurus · 3 June 2024 10:21

How to deploy on MAAS

This guide aims to provide a quick start to deploying Charmed PostgreSQL on MAAS. It summarizes the instructions from the Build a MAAS and LXD environment with Multipass Tutorial to set up and tear down a playground environment.

If you want to deploy PostgreSQL on MAAS in a production environment, refer to the official Bootstrap MAAS Tutorial followed by the Charmed PostgreSQL Tutorial.

For further details and explanation about each step, remember you can refer to the original tutorial.

Bootstrap a Multipass VM

Install Multipass and launch a VM:

sudo snap install multipass

wget -qO- https://raw.githubusercontent.com/canonical/maas-multipass/main/maas.yml \
 | multipass launch --name maas -c8 -m12GB -d50GB --cloud-init -

The wget command provides a cloud-init file that will set up the VM’s LXD and MAAS environment.

Configure MAAS

1. Find your MAAS IP with

multipass list

2. Open http://<MAAS_IP>:5240/MAAS/ and log in with the default credentials: username=admin, password=admin.

3. Complete the additional MAAS configuration in the welcome screen.

4. Wait for image downloads to complete on http://:5240/MAAS/r/images

Make sure you are downloading 22.04 images as well (20.04 is the current default).

The LXD machine will be up and running after the images downloading and sync is completed.

5. Navigate to http://:5240/MAAS/r/tags and create a tag with tag-name=juju. Assign it to the LXD machine.

A note on DHCP

MAAS uses DHCP to boot and install new machines. You must enable DHCP manually if you see this banner on MAAS pages:
image1215×82 32.5 KB

Make sure to enable DHCP service inside the MAAS VM only.

Use the internal VM network fabric-1 on 10.10.10.0/24 and choose a range (e.g. 10.10.10.100-10.10.10.120). Check the official MAAS manual for more information about enabling DHCP.

6. Finally, dump MAAS admin user API key to add as Juju credentials later:

multipass exec maas -- sudo maas apikey --username admin

Register MAAS with Juju

1. Enter the Multipass shell and install juju:

multipass shell maas
sudo snap install juju

2. Add MAAS cloud and credentials into juju.

These commands are interactive, so the following code block shows the commands followed by a sample output. Make sure to enter your own information when prompted by juju.

juju add-cloud

> Since Juju 2 is being run for the first time, downloading latest cloud information. Fetching latest public cloud list... Your list of public clouds is up to date, see `juju clouds`. Cloud Types
>    maas
>    manual
>    openstack
>    oracle
>    vsphere
> 
> Select cloud type: maas
> Enter a name for your maas cloud: maas-cloud 
> Enter the API endpoint url: http://<MAAS_IP>:5240/MAAS
> Cloud "maas-cloud"

juju add-credential maas-cloud 

> ...
> Enter credential name: maas-credentials
> 
> Regions
>   default
> Select region [any region, credential is not region specific]: default
> ...
> Using auth-type "oauth1". 
> Enter maas-oauth: $(paste the MAAS Keys copied from the output above or from http://YOUR_MAAS_IP:5240/MAAS/r/account/prefs/api-keys ) 
> Credential "maas-credentials" added locally for cloud "maas-cloud".

3. Bootstrap Juju.

Add the flags --credential if you registered several MAAS credentials, and --debug if you want to see bootstrap details:

juju bootstrap --constraints tags=juju maas-cloud maas-controller

Deploy Charmed PostgreSQL on MAAS

juju add-model postgresql maas-cloud
juju deploy postgresql --channel 14/stable

Sample juju status output:

Model       Controller       Cloud/Region        Version  SLA          Timestamp
postgresql  maas-controller  maas-cloud/default  3.1.8    unsupported  12:50:26+02:00

App         Version  Status  Scale  Charm       Channel    Rev  Exposed  Message
postgresql  14.10    active      1  postgresql  14/stable  363  no       Primary

Unit           Workload  Agent  Machine  Public address  Ports     Message
postgresql/0*  active    idle   0        10.10.10.5      5432/tcp  Primary

Machine  State    Address     Inst id        Base          AZ       Message
0        started  10.10.10.5  wanted-dassie  ubuntu@22.04  default  Deployed

Test your Charmed PostgreSQL deployment

Check the Testing reference to test your deployment.

Clean up the environment

To stop your VM, run:

multipass stop maas

If you’re done with testing and would like to free up resources on your machine, you can remove the VM entirely.

Warning: When you remove the VM as shown below, you will lose all the data in PostgreSQL and any other applications inside it!

For more information, see the docs for multipass delete.

To completely delete your VM and all its data, run:

multipass delete --purge maas

If you expect having several concurrent connections frequently, it is highly recommended to deploy PgBouncer alongside PostgreSQL. For more information, read our explanation about Connection pooling.