diff --git a/content/en/docs/concepts/storage/persistent-volumes.md b/content/en/docs/concepts/storage/persistent-volumes.md index 16f0b8ed3b..074fe9f759 100644 --- a/content/en/docs/concepts/storage/persistent-volumes.md +++ b/content/en/docs/concepts/storage/persistent-volumes.md @@ -540,6 +540,15 @@ In the CLI, the access modes are abbreviated to: * RWX - ReadWriteMany * RWOP - ReadWriteOncePod +{{< note >}} +Kubernetes uses volume access modes to match PersistentVolumeClaims and PersistentVolumes. +In some cases, the volume access modes also constrain where the PersistentVolume can be mounted. +Volume access modes do **not** enforce write protection once the storage has been mounted. +Even if the access modes are specified as ReadWriteOnce, ReadOnlyMany, or ReadWriteMany, they don't set any constraints on the volume. +For example, even if a PersistentVolume is created as ReadOnlyMany, it is no guarantee that it will be read-only. +If the access modes are specified as ReadWriteOncePod, the volume is constrained and can be mounted on only a single Pod. +{{< /note >}} + > __Important!__ A volume can only be mounted using one access mode at a time, even if it supports many. For example, a GCEPersistentDisk can be mounted as ReadWriteOnce by a single node or ReadOnlyMany by many nodes, but not at the same time.