High Availability but Lean Kubernetes Cluster

A High Availability, frugal Kubernetes cluster using Kubespray optimized for Contabo VPS. Deploy enterprise-grade Kubernetes at 1/10th the cost of managed solutions.

Key Features

• Cost-Optimized: €15-20/month for a 3-node cluster (vs €150-300 for managed K8s)
• Full Kubernetes: Latest version with containerd runtime
• Enterprise Addons: MetalLB, Kube-VIP, Gateway API CRDs
• Flexible Architecture: Single or multi-node, control-plane + worker combinations
• Template-Based: TypeScript templates for consistent, reproducible deployments

Cost Comparison

Configuration	HA Lean Cluster (Contabo)	AWS EKS	GCP GKE	Azure AKS	Digital Ocean
3-node cluster (minimal)	€14.97/month	~€150/month	~€135/month	~€160/month	~€60/month
3-node cluster (recommended)	€29.97/month	~€300/month	~€270/month	~€320/month	~€120/month
5-node cluster	€49.95/month	~€500/month	~€450/month	~€530/month	~€200/month

Contabo VPS vs Cloud Providers

VPS Type	Contabo Specs	Contabo Price	AWS Equivalent	AWS Price	GCP Equivalent	GCP Price	Azure Equivalent	Azure Price
VPS S	4 vCPU, 8GB RAM	€4.99/month	t3.large	~€70/month	e2-standard-2	~€60/month	B2s v2	~€65/month
VPS M	6 vCPU, 16GB RAM	€9.99/month	t3.xlarge	~€140/month	e2-standard-4	~€120/month	B4ms v2	~€130/month
VPS L	8 vCPU, 32GB RAM	€14.99/month	t3.2xlarge	~€280/month	e2-standard-8	~€240/month	B8ms v2	~€260/month

Cost Savings Factors

• No Control Plane Fees: Managed K8s services charge €70-100/month for the control plane
• Lower VM Pricing: Contabo VPS costs 80-90% less than equivalent cloud instances
• Included Load Balancing: MetalLB eliminates the need for paid load balancers (€20-30/month)
• Optimized Resource Usage: Flexible node roles allow for efficient resource allocation

Activated Features

• Kubernetes Core: v1.31.4, containerd runtime, secret encryption at rest
• Networking: Calico CNI, IPVS proxy mode with strict ARP, NodeLocal DNS cache
• High Availability: MetalLB (BGP Layer 3 mode), Kube-VIP (ARP mode), supplementary addresses in SSL keys
• Enterprise Features: Gateway API CRDs, secure communication

Quick Start

git clone https://github.com/ctnr.io/ha-lean-cluster.git
cd ha-lean-cluster
make login
make generate
make apply 

Hardware Requirements

• Minimal: 1 Contabo VPS S (4 vCPU, 8GB RAM) - €4.99/month
• Recommended: 3 Contabo VPS S instances - €14.97/month

Configuration & Node Naming

• Core Files: inventory.ini.ts, kubeconfig.yml.ts, group_vars/k8s_cluster/k8s-cluster.yml.ts, group_vars/k8s_cluster/addons.yml.ts
• Node Naming: Each node name must start with the domain name prefix (ctnr.io-) followed by the role:
  • Control Plane: <domain-name>-control-plane-X[-etcd][-worker]
  • ETCD: <domain-name>-etcd-X
  • Worker: <domain-name>-worker-X[-etcd]
  • Examples: <domain-name>-control-plane-0-etcd, <domain-name>-worker-0, <domain-name>-etcd-0

⚠️ Important Warning

DO NOT change the first control plane node (-control-plane-0) without understanding the implications!

The first control plane node is critical for cluster stability. Modifying or removing it incorrectly can cause the entire cluster to fail. If you need to replace the first control plane node, follow these steps:

1. Rename your current nodes so that <domain-name>-control-plane-1 becomes <domain-name>-control-plane-0 and vice versa
2. Apply the configuration
3. Only then remove the original control plane node

Testing

The project includes automated tests to verify that key components are working correctly:

• Ingress Testing: Tests that the Nginx ingress controller is properly configured and can route traffic to services
  • Run with: make test-ingress or deno test -A tests/ingress_test.ts
  • The test creates a test namespace, deployment, service, and ingress with a custom domain name
  • It verifies connectivity using host-based routing with the domain name from your configuration
  • Test fixtures are located in tests/fixtures/ directory

Next Steps & Roadmap

• Next: Implement volume provisioning, configure auto-scaling, deploy workloads, add monitoring
• Roadmap: Automated provisioning, one-click deployment, backup solution, multi-region support, performance benchmarks

Professional Support

Need help with setup, maintenance, or customization? Contact us directly for professional support services. We can help with:

• Initial cluster deployment and configuration
• Ongoing maintenance and updates
• Performance optimization
• Custom integrations and workload deployment
• Training and knowledge transfer

Email: [email protected]

License

MIT License - see LICENSE file