To ensure a highly available application in Kubernetes for critical applications, the following best practices should be followed:
Redundancy Across Nodes: Configure multiple replicas for your application and deploy them on different nodes of the cluster to avoid a single point of failure. The Kubernetes ReplicaSets or Deployments can be used for the management of pod replicas.
Readiness and Liveness Probes: The readiness probes should be configured to route traffic only to healthy pods and liveness probes that can automatically restart failed containers.
Enable Horizontal Pod Autoscaling: To dynamically scale the number of pods based on metrics like CPU or memory usage to automatically handle traffic spikes.
Distribute Across Zones: Utilize the Kubernetes Node Affinity and Pod Anti-Affinity rules to actively distribute workloads across availability zones for fault tolerance.
Resource Requests and Limits: Define the CPU and memory requests/limits in pod specifications to avoid resource contention and ensure predictable performance.
Load Balancers and Ingress Controllers: Leverage external load balancers and Kubernetes Ingress to distribute traffic while accessing pods even in updates.
Disaster Recovery Plan: Backup stateful applications with Persistent Volume Snapshots or third-party tools, such as Velero.
Monitoring and Alerting: Integrate tools, including Prometheus, Grafana, and Kubernetes-native alerts, monitoring cluster health and responding proactively to failures.
