Thank you very much for your response. I've spent some time investigating deeper and can reveal interesting details.
Hosted engine is now "Software Version:4.5.4-1.el8". Operating systems have been upgraded to "Red Hat Enterprise Linux 8.7 (Ootpa)".
oVirt repository centos-ovirt45 is present, it's accompanying repos are too:
repo id repo name
codeready-builder-for-rhel-8-x86_64-rpms Red Hat CodeReady Linux Builder for RHEL 8 x86_64 (RPMs)
rhel-8-for-x86_64-appstream-rpms Red Hat Enterprise Linux 8 for x86_64 - AppStream (RPMs)
rhel-8-for-x86_64-baseos-rpms Red Hat Enterprise Linux 8 for x86_64 - BaseOS (RPMs)
centos-ceph-pacific CentOS-8-stream - Ceph Pacific
centos-gluster10 CentOS-8-stream - Gluster 10
centos-nfv-openvswitch CentOS-8 - NFV OpenvSwitch
centos-opstools CentOS-OpsTools - collectd
centos-ovirt45 CentOS Stream 8 - oVirt 4.5
cs8-extras CentOS Stream 8 - Extras
cs8-extras-common CentOS Stream 8 - Extras common packages
ovirt-45-centos-stream-openstack-yoga CentOS Stream 8 - oVirt 4.5 - OpenStack Yoga Repository
ovirt-45-upstream oVirt upstream for CentOS Stream 8 - oVirt 4.5
Hosts report "Cluster Compatibility Version: 4.2,4.3,4.4,4.5,4.6,4.7" on UI.
The problem actually looks somewhat related to UI. I've tried to _not_ change anything on "Edit Cluster" dialogue window and just pressed "OK" and still got the "Error while executing action: Cannot disable gluster service on the cluster as it contains volumes" response.
By looking on UI I see that "Enable Gluster Service" checkbox is empty and is grayed out. Looks like UI "thinks" that Glusterfs is disabled and when I hit "OK" it tries to apply this as a change.
I've checked engine-config:
[root@he ~]# engine-config -g AllowClusterWithVirtGlusterEnabled
Picked up JAVA_TOOL_OPTIONS: -Dcom.redhat.fips=false
AllowClusterWithVirtGlusterEnabled: true version: general
It is "True". And it is protected. I was unable to set it to "False" - just tried out of curiosity.
Next I've opened Web Developer Tools in my browser, found '<input type="checkbox" value="on" id="ClusterPopupView_enableGlusterService" tabindex="17" disabled="" style="vertical-align: top;">' and removed the word 'disabled'. I've checked this checkbox and tried hitting "OK".
This time the dialog worked and after reopening it I see the checkbox grayed out but now it is checked. oVirt works, nothing is changed or ruined. But one more observation: this checkbox stays checked till Hosted Engine reboot. After a reboot it is unchecked again.
OK, supposedly I can proceed. I've tried changing the Compatibility Version to 4.7 and hit OK again.
This time I've got another error on UI "Cannot update cluster because the update triggered update of the VMs/Templates and it failed for the following: HostedEngine":
Hosted Engine is the only VM running in the whole cluster. And according to /var/log/ovirt-engine/engine.log the problem is probably something else as I see this:
2023-01-04 11:21:23,199+03 INFO [org.ovirt.engine.core.bll.UpdateClusterCommand] (default task-5) [a61e4bd4-ac1e-4ec9-a2af-86c889027ba6] Running command: UpdateClusterCommand internal: false. Entities affected : ID: 5f56b384-875f-11ed-87f4-00163e2e6261 Type: ClusterAction group EDIT_CLUSTER_CONFIGURATION with role type ADMIN
2023-01-04 11:21:23,561+03 ERROR [org.ovirt.engine.core.bll.UpdateVmCommand] (default task-5) [7db95745] Error during ValidateFailure.: java.lang.IllegalArgumentException: No enum constant org.ovirt.engine.core.common.businessentities.ArchitectureType.
at java.base/java.lang.Enum.valueOf(Enum.java:240)
at org.ovirt.engine.core.common//org.ovirt.engine.core.common.businessentities.ArchitectureType.valueOf(ArchitectureType.java:8)
at org.ovirt.engine.core.utils//org.ovirt.engine.core.utils.OsRepositoryImpl.getArchitectureFromOS(OsRepositoryImpl.java:268)
at deployment.engine.ear.bll.jar//org.ovirt.engine.core.bll.validator.VmValidationUtils.isOsTypeSupported(VmValidationUtils.java:45)
... many-many more lines
It looks like it couldn't read the org.ovirt.engine.core.common.businessentities.ArchitectureType constant. Or something like that, my programming skills are poor.
I'm attaching the full log output as a file. Hope maillist allows it to be sent.
I'm stuck on this. Hope for your help. Please tell me if I can provide more info to you.
Thank you.