{"id":3965,"date":"2024-04-02T17:17:58","date_gmt":"2024-04-02T17:17:58","guid":{"rendered":"https:\/\/code2deploy.com\/blog\/?p=3965"},"modified":"2024-04-02T17:17:59","modified_gmt":"2024-04-02T17:17:59","slug":"kubernetes-pods","status":"publish","type":"post","link":"https:\/\/code2deploy.com\/blog\/kubernetes-pods\/","title":{"rendered":"Kubernetes Pods"},"content":{"rendered":"\n

Pod is the basic building block of Kubernetes, the smallest deployable unit <\/em><\/strong>in the Kubernetes that can be created and managed.<\/p>\n\n\n\n

A pod is a group of one or more containers (such as Docker containers) with shared storage\/network, and a specification for how to run the containers.<\/p>\n\n\n\n

A pod represents a single instance of an application in Kubernetes.<\/p>\n\n\n\n

Here is the manifest<\/strong> for a Pod:<\/p>\n\n\n\n

Create a manifest file for pod creation <\/p>\n\n\n\n

$ sudo vim nginx.yaml<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Enter the following manifest <\/p>\n\n\n\n

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  containers:
  – name: nginx
    image: nginx:latest
    imagePullPolicy: IfNotPresent
    ports:
    – containerPort: 80<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Create a pod:<\/strong><\/p>\n\n\n\n

$ kubectl create -f nginx.yaml<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

pod “nginx” created<\/p>\n\n\n\n

Verify the pod is running:<\/strong><\/p>\n\n\n\n

$ kubectl get pod nginx<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Expected Output: <\/strong><\/p>\n\n\n\n

NAME    READY   STATUS    RESTARTS   AGE
nginx   1\/1     Running   0          89s<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Check the pod created in the which node<\/strong><\/p>\n\n\n\n

kubectl get pod -o wide<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Expected Output: :<\/strong><\/p>\n\n\n\n

NAME    READY   STATUS    RESTARTS   AGE     IP              NODE           NOMINATED NODE   READINESS GATES
nginx   1\/1     Running   0          2m50s   192.168.230.9   k8s-worker-1   <none>           <none><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Edit pod configuration:<\/strong><\/p>\n\n\n\n

$ kubectl edit pod nginx<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

You can edit the Pod-YAML<\/strong> using this command <\/p>\n\n\n\n

Expose this pod using service, Let\u2019s create a service<\/p>\n\n\n\n

Note: <\/strong>we will learn more about the server on the next page <\/p>\n\n\n\n

Create a service manifest file <\/strong><\/p>\n\n\n\n

$ sudo vim nginx-svc.yaml<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Enter the following manifest <\/p>\n\n\n\n

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  selector:
    app: nginx
  ports:
    – protocol: TCP
      port: 80
      targetPort: 80
      nodePort: 31423
  type: NodePort<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

In this configuration, the label of the Pod<\/strong> is specified within the Service’s selector section<\/strong>. This allows the Service to identify and expose the Pod associated with that specific label.<\/p>\n\n\n\n

Check whether the Service was Created or not<\/p>\n\n\n\n

$ kubectl get svc -n default <\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Expected Output: <\/p>\n\n\n\n

NAME            TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)             AGE
nginx-service   NodePort    10.108.209.184   <none>        80:31423\/TCP        14s<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Service has been created, now let\u2019s Verify the Nginx from the browser http:\/\/Node-IP:31423<\/strong><\/p>\n\n\n\n

Delete a pod<\/strong><\/p>\n\n\n\n

$ kubectl delete -f nginx.yaml<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Expected Output: <\/p>\n\n\n\n

pod “nginx” deleted<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

        — or —<\/p>\n\n\n\n

$ kubectl delete pod nginx<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

pod “nginx” deleted<\/p>\n\n\n\n

Delete the service <\/p>\n\n\n\n

$ kubectl delete -f nginx-svc.yaml  <\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Pod Lifecycle<\/strong><\/h3>\n\n\n\n

Here are the possible values for STATUS:<\/p>\n\n\n\n

    \n
  • Pending State<\/strong><\/li>\n<\/ul>\n\n\n\n

    The Pod has been accepted by the Kubernetes system, but one or more of the Container images has not been created. This includes time before being scheduled as well as time spent downloading images over the network, which could take a while.<\/p>\n\n\n\n

      \n
    • Running State<\/strong><\/li>\n<\/ul>\n\n\n\n

      The Pod has been bound to a node, and all of the Containers have been created. At least one Container is still running or is in the process of starting or restarting.<\/p>\n\n\n\n

        \n
      • Succeeded State<\/strong><\/li>\n<\/ul>\n\n\n\n

        All Containers in the Pod have terminated in success, and will not be restarted.<\/p>\n\n\n\n

          \n
        • Failed State<\/strong><\/li>\n<\/ul>\n\n\n\n

          All Containers in the Pod have terminated, and at least one Container has terminated in failure. That is, the Container either exited with non-zero status or was terminated by the system.<\/p>\n\n\n\n

            \n
          • Unknown State<\/strong><\/li>\n<\/ul>\n\n\n\n

            For some reason, the state of the Pod could not be obtained, typically due to an error in communicating with the host of the Pod.<\/p>\n\n\n\n

              \n
            • Completed State<\/strong><\/li>\n<\/ul>\n\n\n\n

              The pod has run to completion as there is nothing to keep it running eg. Completed Jobs.<\/p>\n\n\n\n

                \n
              • CrashLoopBackOff State<\/strong><\/li>\n<\/ul>\n\n\n\n

                This means that one of the containers in the pod has exited unexpectedly,<\/em><\/strong> and perhaps with a non-zero error code even after restarting due to the restart policy.<\/p>\n\n\n\n

                Multi-Container Pods<\/strong><\/h3>\n\n\n\n
                  \n
                1. Pods are designed to support multiple containers. The containers in a Pod are automatically co-located and co-scheduled on the same node in the cluster.<\/li>\n<\/ol>\n\n\n\n
                    \n
                  1. The containers can share resources and dependencies, communicate with one another, and coordinate when and how they are terminated.<\/li>\n<\/ol>\n\n\n\n
                      \n
                    1. The “one container per Pod”<\/strong> model is the most common use case and Kubernetes manages the Pods rather than the containers directly.<\/li>\n<\/ol>\n\n\n\n

                      Here is an example of a multi-container pod<\/strong><\/p>\n\n\n\n

                      apiVersion: v1
                      kind: Pod
                      metadata:
                        name: nginx-web
                      spec:
                        volumes:
                        – name: shared-files
                          emptyDir: {}
                        – name: nginx-config-volume
                          configMap:
                            name: nginx-config
                        containers:
                        – name: app
                          image: php-app:1.0
                          volumeMounts:
                          – name: shared-files
                            mountPath: \/var\/www\/html
                        – name: nginx
                          image: nginx:latest
                          volumeMounts:
                          – name: shared-files
                            mountPath: \/var\/www\/html
                          – name: nginx-config-volume
                            mountPath: \/etc\/nginx\/nginx.conf
                            subPath: nginx.conf<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

                      Init Containers<\/strong><\/h3>\n\n\n\n

                      Like multiple containers in a pod, it can also have one or more init containers, which are run before the application containers are started.<\/p>\n\n\n\n

                        \n
                      • Init containers always run to completion.<\/li>\n\n\n\n
                      • Each init container must be completed successfully before the next one starts.<\/li>\n<\/ul>\n\n\n\n

                        Here is an example of init containers<\/strong><\/p>\n\n\n\n

                        apiVersion: v1
                        kind: Pod
                        metadata:
                          name: wordpress
                        spec:
                          containers:
                          – image: wordpress:latest
                            name: wordpress
                            ports:
                            – containerPort: 80
                              name: wordpress
                          initContainers:
                          – name: change-permissions
                            image: busybox
                            command: [‘sh’, ‘-c’, ‘chown www-data:www-data \/var\/www\/html && chmod -R 755 \/var\/www\/html’]<\/td><\/tr><\/tbody><\/table><\/figure>\n","protected":false},"excerpt":{"rendered":"

                        More details about pod, manifest creation, delation, edit, update, Pod Lifecycle, Multi-Container Pods, Init Containers. <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,218],"tags":[461,460,140,427,459,458],"class_list":["post-3965","post","type-post","status-publish","format-standard","hentry","category-kubernetes","category-pod","tag-init-containers","tag-multi-container-pods","tag-pod","tag-pod-commands","tag-pod-lifecycle","tag-pod-manifest"],"yoast_head":"\nKubernetes Pods - code2deploy.com<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blog.code2deploy.com\/kubernetes-pods\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Kubernetes Pods - code2deploy.com\" \/>\n<meta property=\"og:description\" content=\"More details about pod, manifest creation, delation, edit, update, Pod Lifecycle, Multi-Container Pods, Init Containers.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/blog.code2deploy.com\/kubernetes-pods\/\" \/>\n<meta property=\"og:site_name\" content=\"code2deploy.com\" \/>\n<meta property=\"article:published_time\" content=\"2024-04-02T17:17:58+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2024-04-02T17:17:59+00:00\" \/>\n<meta name=\"author\" content=\"enam\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"enam\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"4 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/blog.code2deploy.com\\\/kubernetes-pods\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blog.code2deploy.com\\\/kubernetes-pods\\\/\"},\"author\":{\"name\":\"enam\",\"@id\":\"https:\\\/\\\/code2deploy.com\\\/blog\\\/#\\\/schema\\\/person\\\/e46930c19b999a87f12566fa8357481b\"},\"headline\":\"Kubernetes Pods\",\"datePublished\":\"2024-04-02T17:17:58+00:00\",\"dateModified\":\"2024-04-02T17:17:59+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/blog.code2deploy.com\\\/kubernetes-pods\\\/\"},\"wordCount\":977,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\\\/\\\/code2deploy.com\\\/blog\\\/#\\\/schema\\\/person\\\/e46930c19b999a87f12566fa8357481b\"},\"keywords\":[\"Init Containers\",\"Multi-Container Pods\",\"pod\",\"Pod Commands\",\"Pod Lifecycle\",\"pod manifest\"],\"articleSection\":[\"Kubernetes\",\"POD\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/blog.code2deploy.com\\\/kubernetes-pods\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/blog.code2deploy.com\\\/kubernetes-pods\\\/\",\"url\":\"https:\\\/\\\/blog.code2deploy.com\\\/kubernetes-pods\\\/\",\"name\":\"Kubernetes Pods - code2deploy.com\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/code2deploy.com\\\/blog\\\/#website\"},\"datePublished\":\"2024-04-02T17:17:58+00:00\",\"dateModified\":\"2024-04-02T17:17:59+00:00\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/blog.code2deploy.com\\\/kubernetes-pods\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/blog.code2deploy.com\\\/kubernetes-pods\\\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/blog.code2deploy.com\\\/kubernetes-pods\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/code2deploy.com\\\/blog\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Kubernetes Pods\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/code2deploy.com\\\/blog\\\/#website\",\"url\":\"https:\\\/\\\/code2deploy.com\\\/blog\\\/\",\"name\":\"code2deploy.com\\\/blog\",\"description\":\"TechOps\",\"publisher\":{\"@id\":\"https:\\\/\\\/code2deploy.com\\\/blog\\\/#\\\/schema\\\/person\\\/e46930c19b999a87f12566fa8357481b\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/code2deploy.com\\\/blog\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":[\"Person\",\"Organization\"],\"@id\":\"https:\\\/\\\/code2deploy.com\\\/blog\\\/#\\\/schema\\\/person\\\/e46930c19b999a87f12566fa8357481b\",\"name\":\"enam\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/d864e2f082f4499f8f1b33f004ec166eea77b9e94738553b120b6dca2410f203?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/d864e2f082f4499f8f1b33f004ec166eea77b9e94738553b120b6dca2410f203?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/d864e2f082f4499f8f1b33f004ec166eea77b9e94738553b120b6dca2410f203?s=96&d=mm&r=g\",\"caption\":\"enam\"},\"logo\":{\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/d864e2f082f4499f8f1b33f004ec166eea77b9e94738553b120b6dca2410f203?s=96&d=mm&r=g\"},\"sameAs\":[\"https:\\\/\\\/code2deploy.com\\\/blog\"],\"url\":\"https:\\\/\\\/code2deploy.com\\\/blog\\\/author\\\/enam\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Kubernetes Pods - code2deploy.com","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/blog.code2deploy.com\/kubernetes-pods\/","og_locale":"en_US","og_type":"article","og_title":"Kubernetes Pods - code2deploy.com","og_description":"More details about pod, manifest creation, delation, edit, update, Pod Lifecycle, Multi-Container Pods, Init Containers.","og_url":"https:\/\/blog.code2deploy.com\/kubernetes-pods\/","og_site_name":"code2deploy.com","article_published_time":"2024-04-02T17:17:58+00:00","article_modified_time":"2024-04-02T17:17:59+00:00","author":"enam","twitter_card":"summary_large_image","twitter_misc":{"Written by":"enam","Est. reading time":"4 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/blog.code2deploy.com\/kubernetes-pods\/#article","isPartOf":{"@id":"https:\/\/blog.code2deploy.com\/kubernetes-pods\/"},"author":{"name":"enam","@id":"https:\/\/code2deploy.com\/blog\/#\/schema\/person\/e46930c19b999a87f12566fa8357481b"},"headline":"Kubernetes Pods","datePublished":"2024-04-02T17:17:58+00:00","dateModified":"2024-04-02T17:17:59+00:00","mainEntityOfPage":{"@id":"https:\/\/blog.code2deploy.com\/kubernetes-pods\/"},"wordCount":977,"commentCount":0,"publisher":{"@id":"https:\/\/code2deploy.com\/blog\/#\/schema\/person\/e46930c19b999a87f12566fa8357481b"},"keywords":["Init Containers","Multi-Container Pods","pod","Pod Commands","Pod Lifecycle","pod manifest"],"articleSection":["Kubernetes","POD"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/blog.code2deploy.com\/kubernetes-pods\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/blog.code2deploy.com\/kubernetes-pods\/","url":"https:\/\/blog.code2deploy.com\/kubernetes-pods\/","name":"Kubernetes Pods - code2deploy.com","isPartOf":{"@id":"https:\/\/code2deploy.com\/blog\/#website"},"datePublished":"2024-04-02T17:17:58+00:00","dateModified":"2024-04-02T17:17:59+00:00","breadcrumb":{"@id":"https:\/\/blog.code2deploy.com\/kubernetes-pods\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/blog.code2deploy.com\/kubernetes-pods\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/blog.code2deploy.com\/kubernetes-pods\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/code2deploy.com\/blog\/"},{"@type":"ListItem","position":2,"name":"Kubernetes Pods"}]},{"@type":"WebSite","@id":"https:\/\/code2deploy.com\/blog\/#website","url":"https:\/\/code2deploy.com\/blog\/","name":"code2deploy.com\/blog","description":"TechOps","publisher":{"@id":"https:\/\/code2deploy.com\/blog\/#\/schema\/person\/e46930c19b999a87f12566fa8357481b"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/code2deploy.com\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":["Person","Organization"],"@id":"https:\/\/code2deploy.com\/blog\/#\/schema\/person\/e46930c19b999a87f12566fa8357481b","name":"enam","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/d864e2f082f4499f8f1b33f004ec166eea77b9e94738553b120b6dca2410f203?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/d864e2f082f4499f8f1b33f004ec166eea77b9e94738553b120b6dca2410f203?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/d864e2f082f4499f8f1b33f004ec166eea77b9e94738553b120b6dca2410f203?s=96&d=mm&r=g","caption":"enam"},"logo":{"@id":"https:\/\/secure.gravatar.com\/avatar\/d864e2f082f4499f8f1b33f004ec166eea77b9e94738553b120b6dca2410f203?s=96&d=mm&r=g"},"sameAs":["https:\/\/code2deploy.com\/blog"],"url":"https:\/\/code2deploy.com\/blog\/author\/enam\/"}]}},"_links":{"self":[{"href":"https:\/\/code2deploy.com\/blog\/wp-json\/wp\/v2\/posts\/3965","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/code2deploy.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/code2deploy.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/code2deploy.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/code2deploy.com\/blog\/wp-json\/wp\/v2\/comments?post=3965"}],"version-history":[{"count":1,"href":"https:\/\/code2deploy.com\/blog\/wp-json\/wp\/v2\/posts\/3965\/revisions"}],"predecessor-version":[{"id":3966,"href":"https:\/\/code2deploy.com\/blog\/wp-json\/wp\/v2\/posts\/3965\/revisions\/3966"}],"wp:attachment":[{"href":"https:\/\/code2deploy.com\/blog\/wp-json\/wp\/v2\/media?parent=3965"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/code2deploy.com\/blog\/wp-json\/wp\/v2\/categories?post=3965"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/code2deploy.com\/blog\/wp-json\/wp\/v2\/tags?post=3965"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}