Maintaining a highly available and reliable Amazon EKS (Elastic Kubernetes Service) cluster is crucial for running production workloads that require 24x7 uptime. Here are some best practices and strategies to ensure your EKS clusters and workloads remain highly available:
1. Multi-AZ Deployment
Deploy your EKS clusters across multiple Availability Zones (AZs) to avoid a single point of failure:
- Node Groups in Multiple AZs: Spread your node groups across multiple AZs.
- Load Balancing: Utilize an Application Load Balancer (ALB) or Network Load Balancer (NLB) to distribute traffic across AZs.
2. Implement Auto Scaling
Implement auto-scaling to handle varying loads and ensure your clusters scale as needed. You can achieve this using both Karpenter and the Cluster Autoscaler.
Karpenter
Karpenter is an open-source, flexible, high-performance Kubernetes cluster autoscaler. It helps to launch right-sized nodes in response to changing application loads in real-time. Karpenter can provision its own set of nodes without relying on EKS managed node groups.
Cluster Autoscaler
The Kubernetes Cluster Autoscaler automatically adjusts the size of the Kubernetes cluster when there are pods that cannot be scheduled due to resource constraints or when there are nodes in the cluster that have been underutilized for a period of time.
By combining Karpenter and Cluster Autoscaler, you can ensure that your EKS clusters scale efficiently to meet demand while maintaining high availability.
3. Backup and Restore
Regularly back up your Kubernetes resources and state to ensure you can recover from failures:
- Velero: Use Velero to back up and restore Kubernetes cluster resources and persistent volumes.
- Custom ETCD Backups: Create scripts to back up the ETCD database and store it in an S3 bucket.
4. Monitoring
Implement robust monitoring to detect and respond to issues promptly:
- Amazon CloudWatch: Monitor cluster and application performance.
- Prometheus and Grafana: Use Prometheus for monitoring and Grafana for visualizing metrics.
- New Relic: Provides comprehensive monitoring and observability for your EKS clusters, including real-time performance insights, advanced analytics, and alerting capabilities. For environments with over 70+ clusters, New Relic may offer superior scalability and ease of use.
5. Logging
Implement effective logging to capture and analyze logs for troubleshooting and auditing:
- AWS CloudTrail: Log API calls and activities for audit purposes.
- Fluentd and Fluent Bit: Use these tools to collect and forward logs to centralized systems for comprehensive analysis.
- Amazon OpenSearch Service: Use this service for log aggregation, search, and analysis.
- Splunk: For best integration with Splunk, consider using Splunk Connect for Kubernetes.
6. Security Best Practices
Ensure your clusters are secure to prevent downtime due to security incidents:
- IAM Roles and Policies: Follow least privilege principles for IAM roles and policies.
- Network Policies: Adopt Zero Trust Network Principles and implement network policies to control traffic between pods using tools like Calico or AWS VPC CNI.
Calico: Provides advanced network policy management and security for K8s clusters
AWS VPC CNI: Integrates with AWS VPC networking to provide IP addresses to pods and manage network policies.
- Secrets Management: Use the CIS Secrets Store CSI Driver, HashiCorp Vault, or External Secrets Operator to securely manage and access secrets within your Kubernetes clusters and also allow Kubernetes secrets to be synced with external secret management systems like AWS Secrets Manager, HashiCorp Vault, and others.
- Policy Management: Use Kyverno to define and enforce policies for your Kubernetes resources, ensuring compliance and best practices.
- Role-Based Access Control (RBAC): Implement RBAC good practices to control access to resources within your Kubernetes clusters based on the roles of individual users or groups. Define roles and permissions clearly to ensure secure access control.
7. Service Mesh
Implement a service mesh like Istio to manage microservices communication, security, and observability.
Istio
Istio provides a robust service mesh that offers traffic management, security features, and observability for microservices.
- Traffic Management: Control the flow of traffic and API calls between services.
- Security: Secure service-to-service communication with strong identity-based authentication and authorization.
- Observability: Gain insights into your services' performance with monitoring and tracing capabilities.
8. Regular Maintenance and Updates
Keep your EKS clusters and their components such as Velero, Calico, and other add-ons up to date:
- Kubernetes Version Upgrades: Regularly update your Kubernetes version to benefit from the latest features and security patches.
- AWS Service Updates: Stay informed about AWS service updates and apply necessary changes.
- Component Upgrades: Regularly update critical add-ons and components like Velero, Calico, and other Kubernetes operators and controllers.
9. Pod Disruption Budgets (PDBs)
To maintain high availability of your Kubernetes workloads during maintenance activities and planned disruptions, implement Pod Disruption Budgets (PDBs):
- Definition: Specify the minimum number of pods that must remain available during voluntary disruptions such as node upgrades or scale-down activities.
- Example
apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
name: my-app-pdb
spec:
minAvailable: 2
selector:
matchLabels:
app: my-app
10. Disaster Recovery Planning
Prepare for potential failures with a disaster recovery plan:
- Cross-Region Replication: Use cross-region replication for critical data.
- Backup and Restore Procedures: Document and test backup and restore procedures.
11. Infrastructure as Code (IaC)
Create, deploy, and support your EKS clusters using Infrastructure as Code (IaC) tools to ensure consistency, repeatability, and scalability:
- Terraform: Use Terraform to define your EKS clusters and related resources as code. This allows you to version control and automate the deployment and management of your infrastructure.
- AWS CloudFormation: Utilize AWS CloudFormation templates to provision and manage your EKS clusters along with other AWS resources. Enhance these templates with Jinja2 for more flexibility and templating capabilities, as seen in use at NBNCo.
12. Deployment Tools
Utilize deployment tools to automate and manage your application deployments efficiently:
- ArgoCD: A declarative, GitOps continuous delivery tool for Kubernetes. ArgoCD monitors your Git repositories and ensures the deployed applications are always in sync with the desired state defined in Git.
- Helm and Helmfile: Use Helm charts to package your Kubernetes applications and Helmfile to manage collections of Helm charts. This simplifies the deployment and management of Kubernetes applications.
- AWS CodeBuild: A fully managed continuous integration service that compiles source code, runs tests, and produces software packages that are ready to deploy. It integrates seamlessly with other AWS services for a comprehensive CI/CD pipeline.
- AWS CDK (Cloud Development Kit): AWS CDK allows you to define cloud infrastructure using familiar programming languages. It simplifies the process of deploying and managing AWS resources, including EKS clusters.
- Terraform: In addition to its use for IaC, Terraform can be employed to manage application deployments and infrastructure changes in a consistent and automated manner.
- Jenkins: An open-source automation server that supports building, deploying, and automating software development projects. Jenkins can be used to set up CI/CD pipelines to automate the deployment of applications to your EKS clusters.
- Ansible: An open-source automation tool that can be used for configuration management, application deployment, and task automation. Ansible can help manage the configuration and deployment of your Kubernetes resources.
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