Kubernetes Error: secret "mongo-config" not found - kubernetes

Question

I'm learning Kubernetes and below are the yaml configuration files:
mongo-config.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: mongo-config
data:
mongo-url: mongo-service
mongo-secret.yaml:
apiVersion: v1
kind: Secret
metadata:
name: mongo-secret
type: Opaque
data:
mongo-user: bW9uZ291c2Vy
mongo-password: bW9uZ29wYXNzd29yZA==
mongo.yaml:
apiVersion: apps/v1
kind: Deployment
metadata:
name: mongo-deployment
labels:
app: mongo
spec:
replicas: 1
selector:
matchLabels:
app: mongo
template:
metadata:
labels:
app: mongo
spec:
containers:
- name: mongodb
image: mongo:5.0
ports:
- containerPort: 27017
env:
- name: MONGO_INITDB_ROOT_USERNAME
valueFrom:
secretKeyRef:
name: mongo-secret
key: mongo-user
- name: MONGO_INITDB_ROOT_PASSWORD
valueFrom:
secretKeyRef:
name: mongo-secret
key: mongo-password
---
apiVersion: v1
kind: Service
metadata:
name: mongo-service
spec:
selector:
app: webapp
ports:
- protocol: TCP
port: 27017
targetPort: 27017
webapp.yaml:
apiVersion: apps/v1
kind: Deployment
metadata:
name: webapp-deployment
labels:
app: webapp
spec:
replicas: 1
selector:
matchLabels:
app: webapp
template:
metadata:
labels:
app: webapp
spec:
containers:
- name: webapp
image: nanajanashia/k8s-demo-app:v1.0
ports:
- containerPort: 3000
env:
- name: USER_NAME
valueFrom:
secretKeyRef:
name: mongo-secret
key: mongo-user
- name: USER_PWD
valueFrom:
secretKeyRef:
name: mongo-secret
key: mongo-password
- name: DB_URL
valueFrom:
secretKeyRef:
name: mongo-config
key: mongo-url
---
apiVersion: v1
kind: Service
metadata:
name: webapp-service
spec:
type: NodePort
selector:
app: webapp
ports:
- protocol: TCP
port: 3000
targetPort: 3000
nodePort: 30100
After starting a test webapp i came across the below error:
NAME READY STATUS RESTARTS AGE
mongo-deployment-7875498c-psn56 1/1 Running 0 100m
my-go-app-664f7475d4-jgnsk 1/1 Running 1 (7d20h ago) 7d20h
webapp-deployment-7dc5b857df-6bx4s 0/1 CreateContainerConfigError 0 29m
which if i try to get more details about the CreateContainerConfigError i get:
~/K8s/K8s-demo$ kubectl describe pod webapp-deployment-7dc5b857df-6bx4s
Name: webapp-deployment-7dc5b857df-6bx4s
Namespace: default
Priority: 0
Node: minikube/192.168.49.2
Start Time: Thu, 06 Jan 2022 12:20:02 +0200
Labels: app=webapp
pod-template-hash=7dc5b857df
Annotations: <none>
Status: Pending
IP: 172.17.0.5
IPs:
IP: 172.17.0.5
Controlled By: ReplicaSet/webapp-deployment-7dc5b857df
Containers:
webapp:
Container ID:
Image: nanajanashia/k8s-demo-app:v1.0
Image ID:
Port: 3000/TCP
Host Port: 0/TCP
State: Waiting
Reason: CreateContainerConfigError
Ready: False
Restart Count: 0
Environment:
USER_NAME: <set to the key 'mongo-user' in secret 'mongo-secret'> Optional: false
USER_PWD: <set to the key 'mongo-password' in secret 'mongo-secret'> Optional: false
DB_URL: <set to the key 'mongo-url' in secret 'mongo-config'> Optional: false
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-wkflh (ro)
Conditions:
Type Status
Initialized True
Ready False
ContainersReady False
PodScheduled True
Volumes:
kube-api-access-wkflh:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
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 30m default-scheduler Successfully assigned default/webapp-deployment-7dc5b857df-6bx4s to minikube
Warning Failed 28m (x12 over 30m) kubelet Error: secret "mongo-config" not found
Normal Pulled 27s (x142 over 30m) kubelet Container image "nanajanashia/k8s-demo-app:v1.0" already present on machine
which seems that the issue with configuration is:
Warning Failed 28m (x12 over 30m) kubelet Error: secret "mongo-config" not found
I don't have a secret with name "mongo-config" but there is a ConfigMap with "mongo-config" name:
>:~/K8s/K8s-demo$ kubectl get secret
NAME TYPE DATA AGE
default-token-gs25h kubernetes.io/service-account-token 3 5m57s
mongo-secret Opaque 2 5m48s
>:~/K8s/K8s-demo$ kubectl get configmap
NAME DATA AGE
kube-root-ca.crt 1 6m4s
mongo-config 1 6m4s
Could you please advice what is the issue here?

Answer 1

You have secretKeyRef in:
- name: DB_URL
valueFrom:
secretKeyRef:
name: mongo-config
key: mongo-url
You have to use configMapKeyRef
- name: DB_URL
valueFrom:
configMapKeyRef:
name: mongo-config
key: mongo-url

Answer 2

Basically your configmap is whats called a config map from literals. The only way to use that config map data as your env variables is :
- name: webapp
image: nanajanashia/k8s-demo-app:v1.0
envFrom:
- configMapRef:
name: mongo-config
Modify you web app deployment yaml this way. Also modify the config map itself . Use DB_URL instead of mongo-url as key.

Answer 3

The mongo secret has to be in the same namespace:
apiVersion: v1
kind: Secret
metadata:
name: mongo-secret
namespace: mongodb
labels:
app.kubernetes.io/component: mongodb
type: Opaque
data:
mongodb-root-password: ""
mongodb-passwords: ""
mongodb-metrics-password: ""
mongodb-replica-set-key: ""