Solution Application Failure

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Case 1: Alpha Namespace

Environment Variables: DB_Host=mysql-service; DB_Database=Not Set; DB_User=root; DB_Password=paswrd; 2003: Can't connect to MySQL server on 'mysql-service:3306' (-2 Name does not resolve)

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Troubleshooting Steps

1. Check Pods in the Alpha Namespace Verify that the pods in the alpha namespace are running correctly.
   k get pods -n alpha
   NAME                         READY   STATUS    RESTARTS   AGE
   webapp-mysql-84fbfc644f-nhfv  1/1     Running   0          3m48s
   mysql                        1/1     Running   0          3m48s
   
2. Set Default Namespace to Alpha To prevent repeatedly specifying the namespace, execute:
   k config set-context --current --namespace=alpha
   
3. Inspect Deployments and Services Confirm that the web application is deployed as a deployment and that the services for both the web application and MySQL exist.
   • To check deployments:
     k get deploy
     NAME            READY   UP-TO-DATE   AVAILABLE   AGE
     webapp-mysql    1/1     1            1           5m4s
     
   • To check services:
     k get svc
     NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
     mysql        ClusterIP   10.43.208.47    <none>        3306/TCP         5m12s
     web-service  NodePort    10.43.232.249   <none>        8080:30081/TCP   5m12s
     
4. Resolve MySQL Name Resolution Issue The error occurs because the application expects the MySQL service name to be mysql-service, but the actual service is named mysql. To fix this, update the MySQL service to match the expected name:
   • Create a YAML file (for example, /tmp/kubectl-edit-3970124164.yaml) with the following content:
     apiVersion: v1
     kind: Service
     metadata:
       name: mysql-service
       namespace: alpha
     spec:
       clusterIP: 10.43.208.47
       ports:
         - port: 3306
           protocol: TCP
           targetPort: 3306
       selector:
         name: mysql
       sessionAffinity: None
       type: ClusterIP
     
   • Then, run:
     kubectl delete svc mysql
     kubectl create -f /tmp/kubectl-edit-3970124164.yaml
     
   • Verify the changes:
     k get svc
     NAME            TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)         AGE
     web-service     NodePort    10.43.232.249   <none>        8080:30081/TCP  8m16s
     mysql-service   ClusterIP   10.43.208.47    <none>        3306/TCP       4s
     

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Case 2: Beta Namespace

Environment Variables: DB_Host=mysql-service; DB_Database=Not Set; DB_User=root; DB_Password=paswrd; 2003: Can't connect to MySQL server on 'mysql-service:3306' (111 Connection refused)

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Troubleshooting Steps

1. Switch Context to Beta
   k config set-context --current --namespace=beta
   
2. Verify Pods and Services
   • Check the pods:
     k get pods
     NAME                                 READY   STATUS    RESTARTS   AGE
     webapp-mysql-84fbfc644f-jwmc          1/1     Running   0          73s
     mysql                                1/1     Running   0          74s
     
   • Check the services:
     k get svc
     NAME             TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)           AGE
     mysql-service    ClusterIP   10.43.114.115   <none>        3306/TCP         84s
     web-service      NodePort    10.43.33.34     <none>        8080:30081/TCP   84s
     
3. Inspect Deployment for Environment Variables Ensure that the deployment’s configuration sets DB_Host to mysql-service:
   k describe deploy webapp-mysql
   
4. Fix Target Port Mismatch The issue was caused by a mismatch in port configuration; the MySQL service’s targetPort was set to 8080 rather than 3306. Update the service configuration:
   • Sample YAML configuration:
     apiVersion: v1
     kind: Service
     metadata:
       name: mysql-service
       namespace: beta
     spec:
       ports:
         - port: 3306
           protocol: TCP
           targetPort: 3306
       selector:
         name: mysql
       type: ClusterIP
     
   • After editing, verify the update:
     k describe svc mysql-service
     Name:              mysql-service
     Namespace:         beta
     Ports:
       - port: 3306/TCP
         targetPort: 3306/TCP
     Endpoints:       10.42.0.12:3306
     

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Case 3: Gamma Namespace

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Troubleshooting Steps

1. Switch Context to Gamma
   k config set-context --current --namespace=gamma
   
2. Verify Pods and Services
   • Inspect pods:
     k get pods
     NAME                          READY   STATUS    RESTARTS   AGE
     mysql                         1/1     Running   0          75s
     webapp-mysql-84fbfc644f-wqm6v  1/1     Running   0          75s
     
   • Inspect services:
     k get svc
     NAME            TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
     mysql-service   ClusterIP   10.43.31.131    <none>        3306/TCP         78s
     web-service     NodePort    10.43.201.61    <none>        8080:30081/TCP   78s
     
3. Examine the Web Service Configuration Confirm that the selectors and endpoints are set properly by describing the service:
   k describe svc web-service
   
   The output should indicate that the web service on port 8080 (exposed via NodePort 30081) correctly maps to the pod IP address (e.g., 10.42.0.1:8080).
4. Review the Deployment Configuration Verify that the deployment’s environment variables (DB_Host, DB_User, DB_Password) and image configuration are correct:
   k describe deploy webapp-mysql
   
5. Check the MySQL Service Selector If endpoints are missing from the MySQL service, confirm that its selector matches the MySQL pod labels. If necessary, adjust the selector:
   k edit svc mysql-service
   

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Case 4: Delta Namespace

Environment Variables: DB_Host=mysql-service; DB_Database=Not Set; DB_User=sql-user; DB_Password=paswrd; 2003: Can't connect to MySQL server on 'mysql-service:3306' (111 Connection refused)

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Troubleshooting Steps

1. Switch Context to Delta
   k config set-context --current --namespace=delta
   
2. Check Pods and Services
   • Inspect pods:
     k get pods
     NAME                                  READY   STATUS    RESTARTS   AGE
     mysql                                 1/1     Running   0          32s
     webapp-mysql-7fbcc4fb8f-dfmnw          1/1     Running   0          32s
     
   • Inspect services:
     k get svc
     NAME             TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE
     mysql-service    ClusterIP   10.43.186.56   <none>        3306/TCP        34s
     web-service      NodePort    10.43.18.113   <none>        8080:30081/TCP  34s
     
3. Review and Update Deployment Credentials Describing the deployment shows that DB_User is set as sql-user:
   k describe deploy webapp-mysql
   
   To resolve the credential issue (the correct user should be root), edit the deployment:
   k edit deploy webapp-mysql
   
   Change DB_User from sql-user to root and save the modification.
4. Monitor the Pod Update Ensure that the updated pod is running. Once the deployment refreshes, the application should successfully connect to the MySQL service.

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Case 5: Epsilon Namespace

Environment Variables: DB_Host=mysql-service; DB_Database=Not Set; DB_User=sql-user; DB_Password=paswrd*1 1045 (28000): Access denied for user 'sql-user'@'10.42.0.19' (using password: YES)

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Troubleshooting Steps

1. Switch Context to Epsilon
   k config set-context --current --namespace=epsilon
   
2. Verify Pods Confirm that both MySQL and the web application pods are running:
   k get pods
   NAME                         READY   STATUS    RESTARTS   AGE
   mysql                        1/1     Running   0          54s
   webapp-mysql-7fbcc4fb8f-lcqvd 1/1     Running   0          54s
   
3. Edit Deployment for Correct Credentials Access and modify the deployment to change DB_User from sql-user to root:
   k edit deploy webapp-mysql
   
   After updating and saving, verify that the error now reflects the root user.
4. Check MySQL Pod Configuration Describe the MySQL pod to confirm the MYSQL_ROOT_PASSWORD:
   k describe pod mysql
   
   If the MYSQL_ROOT_PASSWORD does not match paswrd as expected, update the MySQL configuration. Since changing pod configurations may require recreating the pod, use the command below:
   k replace --force -f /tmp/kubectl-edit-31959777508.yaml
   

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Case 6: Zeta Namespace

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Troubleshooting Steps

1. Switch Context to Zeta
   k config set-context --current --namespace=zeta
   
2. Inspect the Web Service Configuration On examining the service, it was discovered that the NodePort was set incorrectly (e.g., 30088 instead of the required 30081). To update the NodePort, edit the web service with the following YAML:
   apiVersion: v1
   kind: Service
   metadata:
     name: web-service
     namespace: zeta
   spec:
     type: NodePort
     ports:
       - port: 8080
         targetPort: 8080
         nodePort: 30081
         protocol: TCP
     selector:
       name: webapp-mysql
   
   Save the file and verify the update:
   k get svc
   NAME          TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
   web-service   NodePort    10.43.72.229    <none>        8080:30081/TCP   ...
   
3. Update Deployment Credentials An “Access denied” error still appeared, indicating that DB_User was set to sql-user instead of root:
   Environment Variables: DB_Host=mysql-service; DB_Database=Not Set; DB_User=sql-user; DB_Password=paswrd; 1045 (28000): Access denied for user 'sql-user'@'10.42.0.22' (using password: YES)
   
   Edit the deployment to update the credential:
   k edit deploy webapp-mysql
   
   Change DB_User from sql-user to root and save. Deploy the updated configuration and verify that the pod is running with the correct credentials.
4. Verify MySQL Pod Password Lastly, check that the MySQL pod’s MYSQL_ROOT_PASSWORD is correctly configured. If it is not, update the value using:
   k replace --force -f /tmp/kubectl-edit-31959777508.yaml
   

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Conclusion