CODEWITHSUNDEEP
javadockerkubernetesmicroservices
طه غرايبه
طه غرايبه

Reputation: 33

In Kubernetes, how can i have an access mode to allow one pod at a time to write and many pods to read only?

I tried to define a PVC:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: master-pvc
spec:
  accessModes:
    - ReadWriteOnce
    - ReadOnlyMany
  resources:
    requests:
      storage: 1Gi

The nodes that need readonly access should define:

volumeMounts:
- name: mastervol
  mountPath: /data/master/
  readOnly: true

The master that needs to read and write, should define:

volumeMounts:
- name: mastervol
  mountPath: /data/master/

Is this a valid way to achieve what i want?

Upvotes: 3

Views: 544

Answers (1)

Michail Alexakis
Michail Alexakis

Reputation: 1595

It is not a node that requests a volumeMount, but a container inside a Pod (many Pods may run in same node).

A PVC is 1-1 bound to a PV using a single access mode (even it supports many) at a time (see also access modes). So, you cannot have a PVC operating at the same time as ReadWriteOnce (for some Pods) and ReadOnlyMany (for some other Pods).

If you want to support 1 writer and many readers, one solution is to let them use a ReadWriteOnce volume and ensure that all Pods run on the same node the volume is mounted (e.g by using node affinity constraints).

Upvotes: 4

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