Quickstart: Deploy an Azure Linux Container Host for AKS cluster using Terraform
Get started with the Azure Linux Container Host using Terraform to deploy an Azure Linux Container Host cluster. After installing the prerequisites, you implement the Terraform code, initialize Terraform, and create and apply a Terraform execution plan.
Terraform enables the definition, preview, and deployment of cloud infrastructure. With Terraform, you create configuration files using HCL syntax. The HCL syntax allows you to specify the cloud provider and elements that make up your cloud infrastructure. After you create your configuration files, you create an execution plan that allows you to preview your infrastructure changes before they're deployed. Once you verify the changes, you apply the execution plan to deploy the infrastructure.
Note
The example code in this article is located in the Microsoft Terraform GitHub repo.
Prerequisites
-
If you don't have an Azure subscription, create an Azure free account before you begin.
If you haven't already configured Terraform, you can do so using one of the following options:
If you don't have an Azure service principal, create a service principal. Make note of the
appId
,display_name
,password
, andtenant
.You need the Kubernetes command-line tool
kubectl
. If you don't have it, download kubectl.
Create an SSH key pair
To access AKS nodes, you connect using an SSH key pair (public and private), which you generate using the ssh-keygen
command. By default, these files are created in the ~/.ssh directory. Running the ssh-keygen
command overwrites any SSH key pair with the same name already existing in the given location.
Go to https://shell.azure.com to open Cloud Shell in your browser.
Run the
ssh-keygen
command. The following example creates an SSH key pair using RSA encryption and a bit length of 4096:ssh-keygen -t rsa -b 4096
For more information about creating SSH keys, see Create and manage SSH keys for authentication in Azure.
Implement the Terraform code
Create a directory in which to test the sample Terraform code and make it the current directory.
Create a file named
providers.tf
and insert the following code:terraform { required_version = ">=1.0" required_providers { azurerm = { source = "hashicorp/azurerm" version = "~>3.0" } random = { source = "hashicorp/random" version = "~>3.0" } } } provider "azurerm" { features {} }
Create a file named
main.tf
and insert the following code:# Generate random resource group name resource "random_pet" "rg_name" { prefix = var.resource_group_name_prefix } resource "azurerm_resource_group" "rg" { location = var.resource_group_location name = random_pet.rg_name.id } resource "random_id" "log_analytics_workspace_name_suffix" { byte_length = 8 } resource "azurerm_log_analytics_workspace" "test" { location = var.log_analytics_workspace_location # The WorkSpace name has to be unique across the whole of azure; # not just the current subscription/tenant. name = "${var.log_analytics_workspace_name}-${random_id.log_analytics_workspace_name_suffix.dec}" resource_group_name = azurerm_resource_group.rg.name sku = var.log_analytics_workspace_sku } resource "azurerm_log_analytics_solution" "test" { location = azurerm_log_analytics_workspace.test.location resource_group_name = azurerm_resource_group.rg.name solution_name = "ContainerInsights" workspace_name = azurerm_log_analytics_workspace.test.name workspace_resource_id = azurerm_log_analytics_workspace.test.id plan { product = "OMSGallery/ContainerInsights" publisher = "Microsoft" } } resource "azurerm_kubernetes_cluster" "k8s" { location = azurerm_resource_group.rg.location name = var.cluster_name resource_group_name = azurerm_resource_group.rg.name dns_prefix = var.dns_prefix tags = { Environment = "Development" } default_node_pool { name = "azurelinuxpool" vm_size = "Standard_D2_v2" node_count = var.agent_count os_sku = "AzureLinux" } linux_profile { admin_username = "azurelinux" ssh_key { key_data = file(var.ssh_public_key) } } network_profile { network_plugin = "kubenet" load_balancer_sku = "standard" } service_principal { client_id = var.aks_service_principal_app_id client_secret = var.aks_service_principal_client_secret } }
Similarly, you can specify the Azure Linux
os_sku
in azurerm_kubernetes_cluster_node_pool.Create a file named
variables.tf
and insert the following code:variable "agent_count" { default = 3 } # The following two variable declarations are placeholder references. # Set the values for these variable in terraform.tfvars variable "aks_service_principal_app_id" { default = "" } variable "aks_service_principal_client_secret" { default = "" } variable "cluster_name" { default = "k8stest" } variable "dns_prefix" { default = "k8stest" } # Refer to https://azure.microsoft.com/global-infrastructure/services/?products=monitor for available Log Analytics regions. variable "log_analytics_workspace_location" { default = "eastus" } variable "log_analytics_workspace_name" { default = "testLogAnalyticsWorkspaceName" } # Refer to https://azure.microsoft.com/pricing/details/monitor/ for Log Analytics pricing variable "log_analytics_workspace_sku" { default = "PerGB2018" } variable "resource_group_location" { default = "eastus" description = "Location of the resource group." } variable "resource_group_name_prefix" { default = "rg" description = "Prefix of the resource group name that's combined with a random ID so name is unique in your Azure subscription." } variable "ssh_public_key" { default = "~/.ssh/id_rsa.pub" }
Create a file named
outputs.tf
and insert the following code:output "client_certificate" { value = azurerm_kubernetes_cluster.k8s.kube_config[0].client_certificate sensitive = true } output "client_key" { value = azurerm_kubernetes_cluster.k8s.kube_config[0].client_key sensitive = true } output "cluster_ca_certificate" { value = azurerm_kubernetes_cluster.k8s.kube_config[0].cluster_ca_certificate sensitive = true } output "cluster_password" { value = azurerm_kubernetes_cluster.k8s.kube_config[0].password sensitive = true } output "cluster_username" { value = azurerm_kubernetes_cluster.k8s.kube_config[0].username sensitive = true } output "host" { value = azurerm_kubernetes_cluster.k8s.kube_config[0].host sensitive = true } output "kube_config" { value = azurerm_kubernetes_cluster.k8s.kube_config_raw sensitive = true } output "resource_group_name" { value = azurerm_resource_group.rg.name }
Create a file named
terraform.tfvars
and insert the following code:aks_service_principal_app_id = "<service_principal_app_id>" aks_service_principal_client_secret = "<service_principal_password>"
Initialize Terraform and create an execution plan
Initialize Terraform and download the Azure modules required to manage your Azure resources using the
terraform init
command.terraform init
Create a Terraform execution plan using the
terraform plan
command.terraform plan -out main.tfplan
The
terraform plan
command creates an execution plan, but doesn't execute it. Instead, it determines what actions are necessary to create the configuration specified in your configuration files. This pattern allows you to verify whether the execution plan matches your expectations before making any changes to actual resources.The optional
-out
parameter allows you to specify an output file for the plan. Using the-out
parameter ensures that the plan you reviewed is exactly what is applied.To read more about persisting execution plans and security, see the security warnings.
Apply the Terraform execution plan using the
terraform apply
command.terraform apply main.tfplan
The
terraform apply
command above assumes you previously ranterraform plan -out main.tfplan
. If you specified a different file name for the-out
parameter, use that same file name in the call toterraform apply
. If you didn't use the-out
parameter, callterraform apply
without any parameters.
Verify the results
Get the resource group name using the following
echo
command.echo "$(terraform output resource_group_name)"
Browse to the Azure portal.
Under Azure services, select Resource groups and locate your new resource group to see the following resources created in this demo:
- Solution: By default, the demo names this solution ContainerInsights. The portal shows the solution's workspace name in parenthesis.
- Kubernetes service: By default, the demo names this service k8stest. (A managed Kubernetes cluster is also known as an AKS/Azure Kubernetes Service.)
- Log Analytics Workspace: By default, the demo names this workspace with a prefix of TestLogAnalyticsWorkspaceName- followed by a random number.
Get the Kubernetes configuration from the Terraform state and store it in a file that kubectl can read using the following
echo
command.echo "$(terraform output kube_config)" > ./azurek8s
Verify the previous command didn't add an ASCII EOT character using the following
cat
command.cat ./azurek8s
If you see
<< EOT
at the beginning andEOT
at the end, remove these characters from the file. Otherwise, you could receive the following error message:error: error loading config file "./azurek8s": yaml: line 2: mapping values are not allowed in this context
.Set an environment variable so kubectl picks up the correct config using the following
export
command.export KUBECONFIG=./azurek8s
Verify the health of the cluster using the
kubectl get nodes
command.kubectl get nodes
When the Azure Linux Container Host cluster was created, monitoring was enabled to capture health metrics for both the cluster nodes and pods. These health metrics are available in the Azure portal. For more information on container health monitoring, see Monitor Azure Kubernetes Service health.
Several key values were output when you applied the Terraform execution plan. For example, the host address, Azure Linux Container Host cluster username, and Azure Linux Container Host cluster password are output.
To view all of the output values, run
terraform output
. To view a specific output value, runecho "$(terraform output <output_value_name>)"
.
Clean up resources
Delete AKS resources
When you no longer need the resources created with Terraform, you can remove them using the following steps.
Run the
terraform plan
command and specify thedestroy
flag.terraform plan -destroy -out main.destroy.tfplan
Remove the execution plan using the
terraform apply
command.terraform apply main.destroy.tfplan
Delete service principal
Caution
Delete the service principal you used in this demo only if you're not using it for anything else.
Get the object ID of the service principal using the
az ad sp list
commandaz ad sp list --display-name "<display_name>" --query "[].{\"Object ID\":id}" --output table
Delete the service principal using the
az ad sp delete
command.az ad sp delete --id <service_principal_object_id>
Troubleshoot Terraform on Azure
Troubleshoot common problems when using Terraform on Azure.
Next steps
In this quickstart, you deployed an Azure Linux Container Host cluster. To learn more about the Azure Linux Container Host and walk through a complete cluster deployment and management example, continue to the Azure Linux Container Host tutorial.