Fix Python App Deployed on Kubernetes Cluster

 Question: One of the DevOps engineers was trying to deploy a python app on Kubernetes cluster. Unfortunately, due to some mis-configuration, the application is not coming up. Please take a look into it and fix the issues. Application should be accessible on the specified nodePort.

The deployment name is python-deployment-devops, its using poroko/flask-demo-appimage. The deployment and service of this app is already deployed.

nodePort should be 32345 and targetPort should be python flask app's default port.

Note: The kubectl on jump_host has been configured to work with the Kubernetes cluster.

Please Note :-  Perform the below commands based on your question server,  user name & other details that might differ. So please read the task carefully before executing it. 

All the Best 👍

Solution:  

1. Check existing running deployment, pods & services

thor@jump_host ~$ kubectl get pods NAME                                         READY   STATUS             RESTARTS   AGE python-deployment-xfusion-66fbc54cf5-q5bb8   0/1     ImagePullBackOff   0          23s thor@jump_host ~$ thor@jump_host ~$ kubectl get deploy NAME                        READY   UP-TO-DATE   AVAILABLE   AGE python-deployment-xfusion   0/1     1            0           29s thor@jump_host ~$ thor@jump_host ~$ kubectl get svc NAME                     TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE kubernetes               ClusterIP   10.96.0.1       <none>        443/TCP          18m python-service-xfusion   NodePort    10.96.103.162   <none>        8080:32345/TCP   50s thor@jump_host ~$

2. Describe the configuration of the deployment

thor@jump_host ~$ kubectl describe deploy Name:                   python-deployment-xfusion Namespace:              default CreationTimestamp:      Fri, 10 Sep 2021 15:16:43 +0000 Labels:                 <none> Annotations:            deployment.kubernetes.io/revision: 1 Selector:               app=python_app Replicas:               1 desired | 1 updated | 1 total | 0 available | 1 unavailable StrategyType:           RollingUpdate MinReadySeconds:        0 RollingUpdateStrategy:  25% max unavailable, 25% max surge Pod Template:   Labels:  app=python_app   Containers:    python-container-xfusion:     Image:        poroko/flask-app-demo     Port:         5000/TCP     Host Port:    0/TCP     Environment:  <none>     Mounts:       <none>   Volumes:        <none> Conditions:   Type           Status  Reason   ----           ------  ------   Available      False   MinimumReplicasUnavailable   Progressing    True    ReplicaSetUpdated OldReplicaSets:  <none> NewReplicaSet:   python-deployment-xfusion-66fbc54cf5 (1/1 replicas created) Events:   Type    Reason             Age   From                   Message   ----    ------             ----  ----                   -------   Normal  ScalingReplicaSet  72s   deployment-controller  Scaled up replica set python-deployment-xfusion-66fbc54cf5 to 1 thor@jump_host ~$ kubectl describe services python-service-xfusion Name:                     python-service-xfusion Namespace:                default Labels:                   <none> Annotations:              <none> Selector:                 app=python_app Type:                     NodePort IP:                       10.96.103.162 Port:                     <unset>  8080/TCP TargetPort:               8080/TCP NodePort:                 <unset>  32345/TCP Endpoints:                Session Affinity:         None External Traffic Policy:  Cluster Events:                   <none> thor@jump_host ~$

3. Refer the logs to identify the  issues 

thor@jump_host ~$ kubectl logs python-deployment-xfusion-66fbc54cf5-q5bb8 Error from server (BadRequest): container "python-container-xfusion" in pod "python-deployment-xfusion-66fbc54cf5-q5bb8" is waiting to start: trying and failing to pull image thor@jump_host ~$

4. Kindly refer to the below video for fixing  issues ahead 

Happy Learning!!!!

Apart from this if you need more clarity,  I have made a  tutorial video on this, please go through and share your comments. Like and share the knowledge