Is Downtime Required for stretched cluster vSphere Version Upgradation

[Himanshusince19]

Hello Team,

I am running a Stretched Cluster with vSphere V6.7 and planned to upgrade to vSphere 8. So presently, the resource of both the Cluster host is under 50%. Customer is asking me to get everything upgraded and for the we are not given any downtime. I would like to know, whether is it possible to get this activity done without downtime or downtime is mandatory.

I was thinking about the  plan to Migrate all the running VM in Host 1 to Host 2, and then upgrade vCenter, Management Host, and Cluster Host. Will there be any compatibility issue while migrating all the VM from host 1 having vSphere v6.7 to Host 2 with vSphere v8

[depping]

you will need 6.7 U3 at minimum:

https://core.vmware.com/resource/vsphere-8-upgrade-scenarios

And yes if you want you could do vCenter first, and then do host by host and moving VMs between the hosts that are upgraded. It should be possible without downtime for the VMs/Apps.