lulzzz/kubernetes-cluster-setup

A method of creating an AKS cluster Terraforms

Introduction

A method of creating a private AKS cluster with Egress filtering using Terraforms and the Flux gitOps operator. The cluster will be setup with either Open Service Mesh or Istio with couple demo applications deployed.

Azure Resources Created

• Private AKS Cluster with Azure AD Pod Identity, KeyVault CSI Driver and OpenService Mesh extensions
• Jumpbox VM
• KeyVault
• Private Zones for AKS and Keyvault

Required Existing Azure Resources

• Virtual Network with subnets
  • kubernetes
  • private-endpoint
  • servers
  • AzureBastionSubnet
• Azure Container Repostiory
• Azure Blob Storage - Terraform state storage
• Azure Bastion - to access jumpbox VM
• Azure Firewall with proper network and application rules
  • Follow this example of using AKS with Azure Firewall using Terraforms
• A Route Table with a route 0.0.0.0/0 to the Azure Firewall internal IP Address

GitHub Actions

Prerequisites

• A task runner deployed in the virtual network where the AKS cluster will be deployed.

• The task runnre VM need to have a User Managed Identity assigned

• Update infrastructure/uat.tfvars with correct values

• Create the follow Secrets in GitHub:

  Secret Name	Secret Name
  ARM_CLIENT_ID	ARM_CLIENT_SECRET
  ARM_SUBSCRIPTION_ID	ARM_TENANT_ID
  STORAGE_ACCESS_KEY	PAT_TOKEN

Steps

1. Trigger Github Action to create the cluster.
2. Terraform will the call the aks-post-creation-configuration.sh script to add Pod Identity and KeyVault CSI Driver
3. GitHub Actions pipeline will then call the aks-flux-configuration.sh script to confiugre flux and execute the GitOps flow

Manual Setup

Prerequisites

• Update infrastructure/osm|istio.tfvars with correct values for your environment

Cluster Creation

1. az extension add --name aks-preview
2. az extension update --name aks-preview
3. az login
4. az feature register --namespace "Microsoft.ContainerService" --name "AKS-AzureKeyVaultSecretsProvider"
5. az feature register --namespace "Microsoft.ContainerService" --name "EnablePodIdentityPreview"
6. az feature register --namespace "Microsoft.ContainerService" --name "AKS-OpenServiceMesh"
7. az feature register --namespace "Microsoft.ContainerService" --name "DisableLocalAccountsPreview"
8. az feature list -o table --query "[?contains(name, 'Microsoft.ContainerService')].{Name:name,State:properties.state}"
   • Wait till the above features are enabled
9. az provider register --namespace Microsoft.ContainerService
10. cd infrastructure
11. terraform init -backend=true -backend-config="access_key=${access_key}" -backend-config="production.terraform.tfstate"
12. terraform plan -out="production.plan" -var "resource_group_name=DevSub_K8S_RG" -var-file="{osm|istio}.tfvars"
13. terraform apply -auto-approve "production.plan"

GitOps BootStrap

1. Access the Jump VM through Azure Bastion
2. export GITHUB_TOKEN=${PAT_TOKEN_FOR_YOUR_REPO}
3. curl -sL https://aka.ms/InstallAzureCLIDeb | sudo bash
4. curl -s https://fluxcd.io/install.sh | sudo bash
5. az login --identity
6. az aks install-cli
7. az aks get-credentials -n ${CLUSTER_NAME} -g ${CLUSTER_RESOURCE_GROUP}
8. kubelogin convert-kubeconfig -l msi
9. echo -n ${ACR_NAME} > ./username.txt
10. az acr credential show -n ${ACR_NAME} --query "passwords[0].value" -o tsv | tr -d '\n' > password.txt
11. kubectl -n flux-system create secret generic https-credentials --from-file=username=./username.txt --from-file=password=./password.txt
12. flux bootstrap git --url=ssh://[email protected]/${user}/kubernetes-cluster-setup --branch=master --path=./cluster-manifests/uat --personal=true --private=false