How to deploy using Terraform
Terraform is an infrastructure automation tool to provision and manage resources in clouds or data centers. To deploy Charmed PostgreSQL using Terraform and Juju, you can use the Juju Terraform Provider.
The easiest way is to start from these examples of terraform modules prepared by Canonical. This page will guide you through a deployment using an example module for PostgreSQL on machines.
For an in-depth introduction to the Juju Terraform Provider, read this Discourse post.
Note: Storage support was added in Juju Terraform Provider version 0.13+.
Summary
- Install Terraform tooling
- Verify the deployment
- Apply the deployment
- Check deployment status
- Clean up
Install Terraform tooling
This guide assumes Juju is installed and you have an LXD controller already bootstrapped. For more information, check the Set up the environment tutorial page.
First, install Terraform Provider and example modules:
sudo snap install terraform --classic
Switch to the LXD provider and create a new model:
juju switch lxd
juju add-model my-model
Clone examples and navigate to the PostgreSQL machine module:
git clone https://github.com/canonical/terraform-modules.git
cd terraform-modules/modules/machine/postgresql
Initialise the Juju Terraform Provider:
terraform init
Verify the deployment
Open the main.tf
file to see the brief contents of the Terraform module:
resource "juju_application" "machine_postgresql" {
name = "postgresql"
model = "my-model"
charm {
name = "postgresql"
channel = "14/stable"
}
config = {
plugin_hstore_enable = true
plugin_pg_trgm_enable = true
}
units = 1
}
Run terraform plan
to get a preview of the changes that will be made:
terraform plan -var "juju_model_name=my-model"
Apply the deployment
If everything looks correct, deploy the resources (skip the approval):
terraform apply -auto-approve -var "juju_model_name=my-model"
Check deployment status
Check the deployment status with
juju status --model lxd:my-model --watch 1s
Sample output:
Model Controller Cloud/Region Version SLA Timestamp
my-model lxd localhost/localhost 3.5.2 unsupported 14:04:26+02:00
App Version Status Scale Charm Channel Rev Exposed Message
postgresql 14.11 active 1 postgresql 14/stable 429 no
Unit Workload Agent Machine Public address Ports Message
postgresql/0* active idle 0 10.142.152.90 5432/tcp Primary
Machine State Address Inst id Base AZ Message
0 started 10.142.152.90 juju-1ea4a4-0 ubuntu@22.04 Running
Continue to operate the charm as usual from here or apply further Terraform changes.
Clean up
To keep the house clean, remove the newly deployed Charmed PostgreSQL by running
terraform destroy -var "juju_model_name=my-model"
Sample output:
juju_application.machine_postgresql: Refreshing state... [id=my-model:postgresql]
Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
- destroy
Terraform will perform the following actions:
# juju_application.machine_postgresql will be destroyed
- resource "juju_application" "machine_postgresql" {
- config = {
- "plugin_hstore_enable" = "true"
- "plugin_pg_trgm_enable" = "true"
} -> null
- constraints = "arch=amd64" -> null
- id = "my-model:postgresql" -> null
- model = "my-model" -> null
- name = "postgresql" -> null
- placement = "0" -> null
- storage = [
- {
- count = 1 -> null
- label = "pgdata" -> null
- pool = "rootfs" -> null
- size = "99G" -> null
},
] -> null
- trust = true -> null
- units = 1 -> null
- charm {
- base = "ubuntu@22.04" -> null
- channel = "14/stable" -> null
- name = "postgresql" -> null
- revision = 429 -> null
- series = "jammy" -> null
}
}
Plan: 0 to add, 0 to change, 1 to destroy.
Changes to Outputs:
- application_name = "postgresql" -> null
Do you really want to destroy all resources?
Terraform will destroy all your managed infrastructure, as shown above.
There is no undo. Only 'yes' will be accepted to confirm.
Enter a value: yes
juju_application.machine_postgresql: Destroying... [id=my-model:postgresql]
juju_application.machine_postgresql: Destruction complete after 1s
Destroy complete! Resources: 1 destroyed.
For more examples of Terraform modules for VM, including PostgreSQL HA and PostgreSQL + PgBouncer, see the other directories in the terraform-modules
repository.
Feel free to contact us if you have any question and collaborate with us on GitHub!