PVC and PV usage - Confusion

Kubernetes-Slack Discussions
#1

Hi,

I am getting confused on how PVC claims a PV. Based on the lectures on CKAD i understood that once we create a PVC, it looks for a PV created and if that is a best fit, the PVC will be created else it will be in a pending state.

I tried replicating this in my system where i used minikube to setup my cluster.

Each time i am creating a PVC it is internally creating a PV and attaching itself to it. Even if i am creating a PV before a PVC, it is doing the same thing.

For e.g.,
Scenario 1:
In my PV i gave a capacity: 500Mi and in PVC i gave as request: 10000000Mi
I was expecting the PVC to be in pending state after creation. But it is internally creating one PV.

Scenario 2:
In my PV i gave a capacity: 500Mi and in PVC i gave as request: 500Mi
Same happens here where PVC creates its own PV and not using the PV i created

Scenario 3:
NO PV.
Created a PV as request: 10000000Mi.
I was expecting the PVC to be in pending state after creation. But it is internally creating one PV.

Any thoughts?

#2

Can you please share YAML examples? Some other parameters could make sense and influence binding.

#4

@kamil-dolmatov I have used the following. Have attached the code outputs as well. Thanks for taking time on this.

I have played around the storages as i experimented

===========================================
apiVersion: v1
kind: PersistentVolume
metadata:
name: myvol
labels:
app: myvol
spec:
accessModes:

  • ReadWriteOnce
    capacity:
    storage: 500Mi
    hostPath:
    path:

============================================

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: myvolclaim
labels:
app: myvolclaim
spec:
accessModes:

  • ReadWriteOnce
    resources:
    requests:
    storage: 500Mi

==============================================

1
11321×466 18.9 KB

#5

@kamil-dolmatov The second output as its not allowing to upload multiple

2
21482×914 28.7 KB

#6

Have you tried specifying volume?

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: myvolclaim
spec:
  volumeName: myvol
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 500Mi
#7

Hello, @itschin2
Are you using minikube? By default, in minikube storage-provisioner addon is enabled.
You can check by running minikube addons list. You are getting different PV because of dynamic provisioning.

#8

As a test you can try after disabling it.

#9

Thanks @Tej-Singh-Rana - This makes sense.