*Describe the issue:*

The documentation doesn't detail how encryption in transit works for an ODF cluster. It just refers to how to enable it in the Deployment Guides very briefly:

> To enable in-transit encryption, select In-transit encryption.
>
> Select a Network.
> Click Next.

There are no references in the Architecture or Troubleshooting guides regarding this feature. For example, one thing that will be worth covering is how the option `ms_mode=secure` is passed to the CephFS mount points. From my lab setup, this is from a pod mounting a CephFS file system with encryption on the wire enabled:

sh-4.4$ mount | grep mnt
10.0.91.79:3300,10.0.93.41:3300,10.0.93.166:3300,10.0.93.53:3300,10.0.93.164:3300:/volumes/csi/csi-vol-05e577bd-11be-4e5c-82b0-c3d2398b5e11/36bfbd9a-2e67-415b-a2eb-7be623b9e0e7 on /mnt type ceph (rw,relatime,seclabel,name=csi-cephfs-node,secret=<hidden>,*ms_mode=secure*,fsid=00000000-0000-0000-0000-000000000000,acl,mds_namespace=my-filesystem)

I thought either would set this parameter:

• Adding the variable `ROOK_CSI_ENABLE_CEPHFS": "true"` to the `rook-ceph-operator-config` cm.
• Setting the kernel mount option `kernelMountOptions: ms_mode=secure` in the CephFS storage class.

However, this is not the case. Neither the cm nor the sc is modified. The encryption annotation

oc get storagecluster ocs-external-storagecluster -n openshift-storage -o json | jq -r '.spec.network.connections'
{
"encryption":

}

in the storagecluster seems to suffice to set the `ms_mode=secure` mount option in the CephFS mount points. More details on how it works behind the scenes will be worth it.

*Describe the task you were trying to accomplish:*

Provide further information on how the encryption in transit feature works internally.

*Provide some further documentation details*

N/A

*Suggestions for improvement:*

Add information about how the option `ms_mode=secure` is set for CephFS mount points.

*Document URL:*

Troubleshooting Guide: https://access.redhat.com/documentation/en-us/red_hat_openshift_data_foundation/4.14/html/troubleshooting_openshift_data_foundation
Architecture Guide: https://access.redhat.com/documentation/en-us/red_hat_openshift_data_foundation/4.14/html/red_hat_openshift_data_foundation_architecture

*Chapter/Section Number and Title:*

N/A, as there's no section covering this feature.

*Product Version:*

ODF 4.14

*Environment Details:*

N/A

*Any other versions of this document that also need this update:*

No

*Additional information:*

N/A