AKS Zone-Pinned PostgreSQL Deployment

This project deploys an Azure Kubernetes Service (AKS) cluster with zone-pinned PostgreSQL nodes using Azure Container Storage for persistent storage.

Architecture

The deployment consists of:

1. AKS Cluster

   • System node pool (3 nodes) in zones 1 and 2
   • PostgreSQL node pool (3 nodes) in zone 1
   • PostgreSQL node pool (3 nodes) in zone 2
   • Azure Container Storage for persistent storage

2. Node Pools

   • System nodes: Standard_D4s_v5 (4 vCPUs)
   • PostgreSQL nodes: Standard_D4s_v5 (4 vCPUs)
   • All nodes support premium storage

3. Storage

   • Azure Container Storage for persistent volumes
   • PostgreSQL nodes labeled with acstor.azure.com/io-engine:acstor
   • Minimum 3 nodes per pool required for Azure Container Storage

Prerequisites

• Azure CLI (version 2.35.0 or later)
• Terraform (version 1.0.0 or later)
• kubectl
• Azure subscription with permissions to create AKS clusters
• Azure Container Storage supported region (westus3)

Deployment Steps

1. Initialize Terraform

   terraform init

2. Review Configuration

   • Check terraform.tfvars for your desired settings
   • Ensure VM sizes meet Azure Container Storage requirements (minimum 4 vCPUs)
   • Verify node counts (minimum 3 nodes per pool)

3. Deploy Infrastructure

   ./run.sh

4. Verify Deployment

   • Check node readiness
   • Verify zone labels
   • Monitor Azure Container Storage pods

Node Pool Configuration

System Node Pool

• Size: Standard_D4s_v5
• Count: 3 nodes
• Zones: 1, 2
• Purpose: System workloads and Azure Container Storage control plane

PostgreSQL Node Pool (Zone 1)

• Size: Standard_D4s_v5
• Count: 3 nodes
• Zone: 1
• Purpose: PostgreSQL primary nodes
• Labels: acstor.azure.com/io-engine:acstor

PostgreSQL Node Pool (Zone 2)

• Size: Standard_D4s_v5
• Count: 3 nodes
• Zone: 2
• Purpose: PostgreSQL secondary nodes
• Labels: acstor.azure.com/io-engine:acstor

Storage Configuration

Azure Container Storage is configured with:

• Data plane components on PostgreSQL nodes
• Control plane components on system nodes
• Minimum 3 nodes per pool for high availability
• Premium storage support via Standard_D4s_v5 VMs

Cleanup

To remove all resources:

terraform destroy -auto-approve

Notes

• Azure Container Storage requires minimum 4 vCPUs per VM
• Each node pool must have at least 3 nodes for Azure Container Storage
• PostgreSQL nodes are tainted to prevent other workloads from scheduling
• System nodes are spread across zones 1 and 2 for high availability

Configuration

Key configuration values in terraform.tfvars:

# Node Sizes
vm_size         = "Standard_D4s_v5"    # System nodes
postgres_vm_size = "Standard_D4s_v5"    # PostgreSQL nodes

# Node Counts
system_node_count        = 3
postgres_zone1_node_count = 3
postgres_zone2_node_count = 3

# Auto-scaling
min_node_count = 3
max_count = 3

# Kubernetes Version
kubernetes_version = "1.30"

Tags and Labels

• Environment-specific tags for resource management
• Workload-specific tags for node pools
• Zone labels for topology awareness
• Node type labels for workload placement

License

Apache License 2.0