The operator does not currently start an orchestration when an OSD deployment is deleted. In the OCS 4.6 timeline we will be looking at that behavior when we convert the CephCluster controller to the controller runtime. Until then a step can be simply added to the node replacement guide to restart the operator.

@Pratik Would that address the issue for now? 
@Raz More details about why you see this as a blocker for 4.4?

The question has not been answered about why this should be a blocker for 4.4. Removing the blocker flag and from 4.4. Per https://bugzilla.redhat.com/show_bug.cgi?id=1817850#c4, this improvement isn't expected to land until OCS 4.6.

Will be part of release-4.6 once we branch it so leaving this to POST until then.

Moving to MODIFIED since the release-4.6 branch is there.

I used a Vsphere LSO 4.6 to check the bug.
From I understand, to verify the bug, we don't need to perform all the steps of node replacement - 
we only need to delete the osd deployment and check that the osd deployment and osd pod should be recreated

Steps I did to verify the bug:

1. Delete the osd deployment
$oc delete deployment rook-ceph-osd-0 -n openshift-storage

2. After approximately 30 seconds the osd deployment and osd pod recreated, 
   and ceph health is OK(without restarting the rook-ceph-operator)


Additional info:

OCP version:
Client Version: 4.3.8
Server Version: 4.6.0-0.nightly-2020-10-20-172149
Kubernetes Version: v1.19.0+d59ce34

OCS verison:
ocs-operator.v4.6.0-134.ci   OpenShift Container Storage   4.6.0-134.ci              Succeeded

cluster version
NAME      VERSION                             AVAILABLE   PROGRESSING   SINCE   STATUS
version   4.6.0-0.nightly-2020-10-20-172149   True        False         20h     Cluster version is 4.6.0-0.nightly-2020-10-20-172149

Rook version
rook: 4.6-67.afaf3353.release_4.6
go: go1.15.0

Ceph version
ceph version 14.2.8-111.el8cp (2e6029d57bc594eceba4751373da6505028c2650) nautilus (stable)

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: Red Hat OpenShift Container Storage 4.6.0 security, bug fix, enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2020:5605