59/100 Troubleshoot Deployment issues in Kubernetes

Last week, the Nautilus DevOps team deployed a redis app on Kubernetes cluster, which was working fine so far. This morning one of the team members was making some changes in this existing setup, but he made some mistakes and the app went down. The deployment name is redis-deployment. The pods are not in running state right now, so please look into the issue and fix the same.

thor@jumphost ~$ kubectl get deployment redis-deployment
NAME               READY   UP-TO-DATE   AVAILABLE   AGE
redis-deployment   0/1     1            0           72s

thor@jumphost ~$ kubectl get pods -l app=redis
NAME                                READY   STATUS              RESTARTS   AGE
redis-deployment-54cdf4f76d-tpd68   0/1     ContainerCreating   0          102s

Use the pod name from above to inspect the pod details (describes it):

thor@jumphost ~$ kubectl describe pod redis-deployment-54cdf4f76d-tpd68
Name:             redis-deployment-54cdf4f76d-tpd68
Namespace:        default
Priority:         0
Service Account:  default
Node:             kodekloud-control-plane/172.17.0.2
Start Time:       Thu, 23 Oct 2025 09:56:15 +0000
Labels:           app=redis
                  pod-template-hash=54cdf4f76d
Annotations:      <none>
Status:           Pending
IP:               
IPs:              <none>
Controlled By:    ReplicaSet/redis-deployment-54cdf4f76d
Containers:
  redis-container:
    Container ID:   
    Image:          redis:alpin
    Image ID:       
    Port:           6379/TCP
    Host Port:      0/TCP
    State:          Waiting
      Reason:       ContainerCreating
    Ready:          False
    Restart Count:  0
    Requests:
      cpu:        300m
    Environment:  <none>
    Mounts:
      /redis-master from config (rw)
      /redis-master-data from data (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-26kqb (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             False 
  ContainersReady   False 
  PodScheduled      True 
Volumes:
  data:
    Type:       EmptyDir (a temporary directory that shares a pod's lifetime)
    Medium:     
    SizeLimit:  <unset>
  config:
    Type:      ConfigMap (a volume populated by a ConfigMap)
    Name:      redis-conig
    Optional:  false
  kube-api-access-26kqb:
    Type:                    Projected (a volume that contains injected data from multiple sources)
    TokenExpirationSeconds:  3607
    ConfigMapName:           kube-root-ca.crt
    ConfigMapOptional:       <nil>
    DownwardAPI:             true
QoS Class:                   Burstable
Node-Selectors:              <none>
Tolerations:                 node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                             node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type     Reason       Age                  From               Message
  ----     ------       ----                 ----               -------
  Normal   Scheduled    2m53s                default-scheduler  Successfully assigned default/redis-deployment-54cdf4f76d-tpd68 to kodekloud-control-plane
  Warning  FailedMount  50s                  kubelet            Unable to attach or mount volumes: unmounted volumes=[config], unattached volumes=[], failed to process volumes=[]: timed out waiting for the condition
  Warning  FailedMount  45s (x9 over 2m53s)  kubelet            MountVolume.SetUp failed for volume "config" : configmap "redis-conig" not found

The last line clearly shows that there is a type for the configmap - it should be referencing redis-config however its showing configmap redis-conig not found.
Also if we review the file further, we see that the image name for the redis container also has a typo and is missing e from the end of alpin.

Edit the file with:

kubectl edit deployment redis-deployment

-- snipped --
          defaultMode: 420
          name: redis-conig  <- Change this to read name: redis-config
        name: config
-- snipped --

redis-container:
    Container ID:   
    Image:          redis:alpin <- Change this to read redis:alpine

thor@jumphost ~$ kubectl edit deployment redis-deployment
deployment.apps/redis-deployment edited

Now delete the stuck pod:

thor@jumphost ~$ kubectl delete pod redis-deployment-54cdf4f76d-tpd68
pod "redis-deployment-54cdf4f76d-tpd68" deleted

Check the rollout and then confirm the pods are up:

thor@jumphost ~$ kubectl rollout status deployment redis-deployment
deployment "redis-deployment" successfully rolled out

thor@jumphost ~$ kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
redis-deployment-7c8d4f6ddf-w889f   1/1     Running   0          2m56s

Summary of fixes