K8s deployment error: `selector` does not match template `labels` - kubernetes

Question

I'm trying to migrate from docker-compose to kubernetes. I had some issues with volume, so what I did is:
kompose convert --volumes hostPath
Then I had another issue
no matches for kind "Deployment" in version "extensions/v1beta1"
So I've changed ApiVersion from extensions/v1beta1 to app/v1 and added "selector". Now I can't manage with that issue:
Error from server (Invalid): error when creating "database-deployment.yaml": Deployment.apps "database" is invalid: spec.template.metadata.labels: Invalid value: map[string]string{"io.kompose.service":"database"}: `selector` does not match template `labels`
Error from server (Invalid): error when creating "phpmyadmin-deployment.yaml": Deployment.apps "phpmyadmin" is invalid: spec.template.metadata.labels: Invalid value: map[string]string{"io.kompose.service":"phpmyadmin"}: `selector` does not match template `labels`
Error from server (Invalid): error when creating "webserver-deployment.yaml": Deployment.apps "webserver" is invalid: spec.template.metadata.labels: Invalid value: map[string]string{"io.kompose.service":"webserver"}: `selector` does not match template `labels`
database-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
annotations:
kompose.cmd: kompose convert --volumes hostPath
kompose.version: 1.19.0 (f63a961c)
creationTimestamp: null
labels:
io.kompose.service: database
app: database
name: database
spec:
selector:
matchLabels:
app: database
template:
metadata:
labels:
io.kompose.service: database
replicas: 1
strategy: {}
template:
metadata:
annotations:
kompose.cmd: kompose convert --volumes hostPath
kompose.version: 1.19.0 (f63a961c)
creationTimestamp: null
labels:
io.kompose.service: database
spec:
containers:
- env:
- name: MYSQL_DATABASE
value: Bazadanerro
- name: MYSQL_PASSWORD
value: P#$$w0rd
- name: MYSQL_ROOT_PASSWORD
value: P#$$w0rd
- name: MYSQL_USER
value: dockerro
image: mariadb
name: mysql
resources: {}
restartPolicy: Always
status: {}
phpmyadmin-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
annotations:
kompose.cmd: kompose convert --volumes hostPath
kompose.version: 1.19.0 (f63a961c)
creationTimestamp: null
labels:
io.kompose.service: phpmyadmin
app: phpmyadmin
name: phpmyadmin
spec:
selector:
matchLabels:
app: phpmyadmin
template:
metadata:
labels:
io.kompose.service: database
replicas: 1
strategy: {}
template:
metadata:
annotations:
kompose.cmd: kompose convert --volumes hostPath
kompose.version: 1.19.0 (f63a961c)
creationTimestamp: null
labels:
io.kompose.service: phpmyadmin
spec:
containers:
- env:
- name: MYSQL_PASSWORD
value: P#$$w0rd
- name: MYSQL_ROOT_PASSWORD
value: P#$$w0rd
- name: MYSQL_USER
value: dockerro
- name: PMA_HOST
value: database
- name: PMA_PORT
value: "3306"
image: phpmyadmin/phpmyadmin
name: phpmyadmins
ports:
- containerPort: 80
resources: {}
restartPolicy: Always
status: {}
And webserver-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
annotations:
kompose.cmd: kompose convert --volumes hostPath
kompose.version: 1.19.0 (f63a961c)
creationTimestamp: null
labels:
io.kompose.service: webserver
app: webserverro
name: webserver
spec:
selector:
matchLabels:
app: webserverro
template:
metadata:
labels:
io.kompose.service: webserver
replicas: 1
strategy:
type: Recreate
template:
metadata:
annotations:
kompose.cmd: kompose convert --volumes hostPath
kompose.version: 1.19.0 (f63a961c)
creationTimestamp: null
labels:
io.kompose.service: webserver
spec:
containers:
- image: webserver
name: webserverro
ports:
- containerPort: 80
resources: {}
volumeMounts:
- mountPath: /var/www/html
name: webserver-hostpath0
restartPolicy: Always
volumes:
- hostPath:
path: /root/webserverro/root/webserverro
name: webserver-hostpath0
status: {}
What am I doing wrong?

Answer 1

The error is self-explanatory: "selector" does not match template "labels".
Edit your YAML files and set the same key-value pairs in both selector.matchLabels and metadata.labels.
spec:
selector:
matchLabels: # <---- This
app: database
template:
metadata:
labels: # <---- This
io.kompose.service: database
Why selector field is important?
The selector field defines how the Deployment finds which Pods to manage. In this case, you simply select a label that is defined in the Pod template (app: nginx). However, more sophisticated selection rules are possible, as long as the Pod template itself satisfies the rule.
Reference
Update:
One possible sample can be:
spec:
selector:
matchLabels:
app.kubernetes.io/name: database
template:
metadata:
labels:
app.kubernetes.io/name: database
Visit recommended labels
Update2:
no matches for kind "Deployment" in version "extensions/v1beta1"
The apiVersion for Deployment object is now apps/v1.
apiVersion: apps/v1 # <-- update here.
kind: Deployment
... ... ...

Answer 2

In all of these files you have two copies of the pod spec template:. These don't get merged; the second one just replaces the first one.
spec:
selector: { ... }
template: # This will get ignored
metadata:
labels:
io.kompose.service: webserver
app: webserverro
template: # and completely replaced with this
metadata:
annotations:
kompose.cmd: kompose convert --volumes hostPath
kompose.version: 1.19.0 (f63a961c)
labels: # without the app: label
io.kompose.service: webserver
spec: { ... }
Remove the first template: block and move the full set of labels into the one template: block that remains.