Kubernetes: pod Demo

Step 1: Let’s check the nodes in the system by executing below command.

kubectl get nodes

$kubectl get nodes
NAME       STATUS   ROLES    AGE   VERSION
minikube   Ready    master   29d   v1.18.0

As you see the output, there is a node with the name ‘minikube’ is running and in Ready state. 

 

Step 2: Let’s get the pods in your system by executing the command ‘kubectl get pods’.

$kubectl get pods
No resources found in default namespace.

Step 3: Let’s run ‘jboss/wildfly’ image on the Kubernetes cluster by executing the below command.

 

kubectl run user-service --image jboss/wildfly

 

In the above command

         Pod name: user-service

         Image to pull from docker hub is: jboss/wildfly

$kubectl run user-service --image jboss/wildfly
pod/user-service created

As you see the output, a user-service pod is created.

 

Step 4: Use the command ‘kubectl get pods’ to get pods information.

$kubectl get pods
NAME           READY   STATUS    RESTARTS   AGE
user-service   1/1     Running   0          83s

As you see that the pod user-service is in Running state.

 

Execute the command ‘kubectl describe pods’ to know information about pods.

$kubectl describe pods
Name:         user-service
Namespace:    default
Priority:     0
Node:         minikube/192.168.99.100
Start Time:   Thu, 04 Jun 2020 19:49:46 +0530
Labels:       run=user-service
Annotations:  <none>
Status:       Running
IP:           172.17.0.6
IPs:
  IP:  172.17.0.6
Containers:
  user-service:
    Container ID:   docker://453f6ec43c0c8fa6701a61f78cd01d77b73b86347656a5b911719a9c27c40e7d
    Image:          jboss/wildfly
    Image ID:       docker-pullable://jboss/wildfly@sha256:67a4f90b213bc2600d08d90e82df58be83813d118d163fbcc8765b6eeaade7e6
    Port:           <none>
    Host Port:      <none>
    State:          Running
      Started:      Thu, 04 Jun 2020 19:49:53 +0530
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-w7rp7 (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             True 
  ContainersReady   True 
  PodScheduled      True 
Volumes:
  default-token-w7rp7:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-w7rp7
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type    Reason     Age        From               Message
  ----    ------     ----       ----               -------
  Normal  Scheduled  <unknown>  default-scheduler  Successfully assigned default/user-service to minikube
  Normal  Pulling    3m24s      kubelet, minikube  Pulling image "jboss/wildfly"
  Normal  Pulled     3m18s      kubelet, minikube  Successfully pulled image "jboss/wildfly"
  Normal  Created    3m18s      kubelet, minikube  Created container user-service
  Normal  Started    3m18s      kubelet, minikube  Started container user-service

From the output, you can confirm below things.

 

Name:         user-service

Pod name is user-service

 

Namespace:    default

Pod running in default namespace.

 

Node:         minikube/192.168.99.100

Pod running on the node minikube

 

Status:       Running

Pod is in running status

 

Apart from these, you can get container id, image, image id etc., from the output.

 

At the end of the output, you see Events; It gives step-by-step details of how the container created.

Events:
  Type    Reason     Age        From               Message
  ----    ------     ----       ----               -------
  Normal  Scheduled  <unknown>  default-scheduler  Successfully assigned default/user-service to minikube
  Normal  Pulling    3m24s      kubelet, minikube  Pulling image "jboss/wildfly"
  Normal  Pulled     3m18s      kubelet, minikube  Successfully pulled image "jboss/wildfly"
  Normal  Created    3m18s      kubelet, minikube  Created container user-service
  Normal  Started    3m18s      kubelet, minikube  Started container user-service

Each pod gets its own internal IP address in the Kubernetes cluster. You can see the IP address of the pods by providing ‘-o wide’ option to get pods command.

$kubectl get pods -o wide
NAME           READY   STATUS    RESTARTS   AGE   IP           NODE       NOMINATED NODE   READINESS GATES
user-service   1/1     Running   0          45m   172.17.0.6   minikube   <none>           <none>

That’s it you are done with the creation of pod.

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