{"id":48670,"date":"2025-03-03T10:33:06","date_gmt":"2025-03-03T10:33:06","guid":{"rendered":"https:\/\/www.devopsschool.com\/blog\/?p=48670"},"modified":"2026-02-21T07:26:32","modified_gmt":"2026-02-21T07:26:32","slug":"most-commonly-used-kubernetes-controllers","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/most-commonly-used-kubernetes-controllers\/","title":{"rendered":"Most commonly used Kubernetes controllers"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

Kubernetes controllers are essential components that continuously regulate the desired state of cluster resources. Here\u2019s a list of the most commonly used Kubernetes controllers<\/strong>:<\/p>\n\n\n\n

1. Deployment Controller<\/strong><\/h3>\n\n\n\n
    \n
  • Manages ReplicaSets<\/strong> to ensure the desired number of pods are running.<\/li>\n\n\n\n
  • Supports rolling updates, rollbacks, and scaling.<\/li>\n<\/ul>\n\n\n\n

    2. ReplicaSet Controller<\/strong><\/h3>\n\n\n\n
      \n
    • Ensures a specified number of pod replicas are running at any given time.<\/li>\n\n\n\n
    • Used primarily by Deployments<\/strong> but can be used independently.<\/li>\n<\/ul>\n\n\n\n

      3. DaemonSet Controller<\/strong><\/h3>\n\n\n\n
        \n
      • Ensures a specific pod runs on every node<\/strong> in the cluster.<\/li>\n\n\n\n
      • Used for logging, monitoring, and networking components (e.g., Fluentd, Prometheus, Calico<\/strong>).<\/li>\n<\/ul>\n\n\n\n

        4. StatefulSet Controller<\/strong><\/h3>\n\n\n\n
          \n
        • Manages stateful applications where each pod has a unique identity and persistent storage (e.g., Databases, Zookeeper, Kafka<\/strong>).<\/li>\n\n\n\n
        • Provides stable network identities<\/strong> and persistent storage.<\/li>\n<\/ul>\n\n\n\n

          5. Job Controller<\/strong><\/h3>\n\n\n\n
            \n
          • Ensures batch jobs execute successfully and terminate upon completion.<\/li>\n\n\n\n
          • Used for one-time tasks like data processing or backups<\/strong>.<\/li>\n<\/ul>\n\n\n\n

            6. CronJob Controller<\/strong><\/h3>\n\n\n\n
              \n
            • Schedules jobs to run at specific times (like cron<\/strong> in Linux).<\/li>\n\n\n\n
            • Used for periodic tasks<\/strong>, e.g., database backups, reporting, etc.<\/li>\n<\/ul>\n\n\n\n

              7. HPA (Horizontal Pod Autoscaler) Controller<\/strong><\/h3>\n\n\n\n
                \n
              • Automatically scales the number of pods<\/strong> based on CPU, memory, or custom metrics.<\/li>\n\n\n\n
              • Useful for dynamically adjusting workloads.<\/li>\n<\/ul>\n\n\n\n

                8. VPA (Vertical Pod Autoscaler) Controller<\/strong><\/h3>\n\n\n\n
                  \n
                • Dynamically adjusts CPU and memory<\/strong> limits for pods.<\/li>\n\n\n\n
                • Helps optimize resource utilization without restarting pods manually.<\/li>\n<\/ul>\n\n\n\n

                  9. Ingress Controller<\/strong><\/h3>\n\n\n\n
                    \n
                  • Manages external access to services using Ingress resources<\/strong>.<\/li>\n\n\n\n
                  • Implements load balancing, SSL termination, and routing<\/strong> (e.g., NGINX Ingress, Traefik, HAProxy<\/strong>).<\/li>\n<\/ul>\n\n\n\n

                    10. Network Policy Controller<\/strong><\/h3>\n\n\n\n
                      \n
                    • Enforces networking rules and controls how pods communicate.<\/li>\n\n\n\n
                    • Works with Calico, Cilium, or Weave<\/strong> for advanced networking.<\/li>\n<\/ul>\n\n\n\n

                      11. Certificate Controller<\/strong><\/h3>\n\n\n\n
                        \n
                      • Automates SSL\/TLS certificate management.<\/li>\n\n\n\n
                      • Works with Cert-Manager<\/strong> for Let’s Encrypt integration.<\/li>\n<\/ul>\n\n\n\n

                        12. Custom Controllers (Operator Pattern)<\/strong><\/h3>\n\n\n\n
                          \n
                        • Extends Kubernetes functionality using Custom Resource Definitions (CRDs)<\/strong>.<\/li>\n\n\n\n
                        • Examples: Prometheus Operator, ArgoCD Operator, Istio Operator<\/strong>.<\/li>\n<\/ul>\n\n\n\n

                          <\/p>\n","protected":false},"excerpt":{"rendered":"

                          Kubernetes controllers are essential components that continuously regulate the desired state of cluster resources. Here\u2019s a list of the most commonly used Kubernetes controllers: 1. Deployment Controller 2. ReplicaSet Controller… <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_joinchat":[],"footnotes":""},"categories":[2],"tags":[],"class_list":["post-48670","post","type-post","status-publish","format-standard","hentry","category-uncategorised"],"_links":{"self":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/48670","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/comments?post=48670"}],"version-history":[{"count":2,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/48670\/revisions"}],"predecessor-version":[{"id":58914,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/48670\/revisions\/58914"}],"wp:attachment":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/media?parent=48670"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/categories?post=48670"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/tags?post=48670"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}