Killer Shell CKA - Application Misconfigured 1

1 개요

Killer Shell CKA - Application Misconfigured 1

https://killercoda.com/killer-shell-cka/scenario/application-misconfigured-1
애플리케이션 네임스페이스 `application1`의 Deployment가 잘못된 ConfigMap 참조로 인해 기동하지 않는 문제를 진단하고 수정하는 실습

2 문제 진단

Deployment의 로그와 상세 정보를 확인하여 원인을 파악한다.

controlplane:~$ k -n application1 get deploy
NAME   READY   UP-TO-DATE   AVAILABLE   AGE
api    0/3     3            0           14m

controlplane:~$ k -n application1 get pod
NAME                   READY   STATUS                       RESTARTS   AGE
api-6768cbb9cc-2smgr   0/1     CreateContainerConfigError   0          16m
api-6768cbb9cc-8xggp   0/1     CreateContainerConfigError   0          16m
api-6768cbb9cc-rv8dd   0/1     CreateContainerConfigError   0          16m

controlplane:~$ k -n application1 describe pod api-6768cbb9cc-2smgr 
...
Events:
  Type     Reason     Age                   From               Message
  ----     ------     ----                  ----               -------
  Normal   Scheduled  17m                   default-scheduler  Successfully assigned application1/api-6768cbb9cc-2smgr to controlplane
  Normal   Pulling    17m                   kubelet            Pulling image "httpd:2.4.52-alpine"
  Normal   Pulled     17m                   kubelet            Successfully pulled image "httpd:2.4.52-alpine" in 5.666s (5.666s including waiting). Image size: 18209719 bytes.
  Normal   Pulled     2m38s (x69 over 17m)  kubelet            Container image "httpd:2.4.52-alpine" already present on machine
  Warning  Failed     2m26s (x71 over 17m)  kubelet            Error: configmap "category" not found

controlplane:~$ k -n application1 get cm
NAME                 DATA   AGE
configmap-category   1      18m
kube-root-ca.crt     1      18m

controlplane:~$ k -n application1 get cm configmap-category -oyaml
apiVersion: v1
data:
  category: abc
kind: ConfigMap
metadata:
  creationTimestamp: "2025-09-22T17:52:21Z"
  name: configmap-category
  namespace: application1
  resourceVersion: "4337"
  uid: 6a2b8558-1d7c-4356-be3d-52717d7bb0ae

3 문제 해결

Deployment 매니페스트에서 잘못된 ConfigMap 이름을 수정한다.

controlplane:~$ k -n application1 edit deploy api

...
    spec:
      containers:
      - env:
        - name: CATEGORY
          valueFrom:
            configMapKeyRef:
              key: category
              #name: category
              name: configmap-category   ## 올바른 ConfigMap 이름으로 수정

4 최종 확인

잠시 후 Deployment가 정상적으로 기동되는 것을 확인한다.

controlplane:~$ k -n application1 get pod
NAME                   READY   STATUS    RESTARTS   AGE
api-77bf88fd44-lwg2d   1/1     Running   0          1s
api-77bf88fd44-p8cxh   1/1     Running   0          4s
api-77bf88fd44-v2cdw   1/1     Running   0          3s

5 같이 보기

Killer Shell CKA