iSCSI adapter IQN may change during the upgrade of ESXi host

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:
If LUN access control is configured on the target side, based on iSCSI adapter IQN, ESXi may not be able to discover the LUN or datastore post upgrade or after a host rebuild.

Environment

VMware vSphere ESXi 7.x

 

VMware vSphere ESXi 8.x

Cause

If the iSCSI adapter IQN is not set by the user then it is auto-generated by ESXi, and may change post upgrade. If access control is configured on the target side, based on the IQN, then the ESXi host may not be able to discover the LUN or datastore (due to the IQN change post upgrade).

Resolution

Version upgrades impacted/not impacted:

• Upgrade from 6.7 to >= 7.0U2 - No issue, the iSCSI adapter IQN is moved from vmkiscsid.db to config store
• Upgrade from 7.0 to >= 7.0U2 - No issue, iSCSI adapter IQN is moved from vmkiscsid.db to config store
• Upgrade from 7.0U1 to >= 7.0U2 - Issue, if all 3 conditions below are met:

1. ESXi is a fresh install of version 7.0 U1 or a particular software/dependent iSCSI adapter was added in 7.0 U1 only
2. The IQN of the iSCSI adapter is not set by the user but automatically generated by ESXi
3. LUN access control is configured on the target side based on the generated IQN

There is no resolution to this issue at this time, see the Workaround section.

Workaround:

To work around the issue:
Prior to the upgrade, use the esxcli get and set commands to set the generated iSCSI adapter IQN explicitly. As the IQN is a user setting it won't change after the upgrade.

For example:

Get the IQN details:
$ esxcli iscsi adapter get -A vmhba67

vmhba67
   Name: iqn.test:<URL>:452738760:67

Set the IQN details:
$ esxcli iscsi adapter set -A vmhba67 -n iqn.test:<URL>:452738760:67