Dear PK,
You can read this page that provides all details and links to sub section: prerequisites, checklist...
But to answer your questions quickly:
vMotion based migrations needs a L2 VPN connection indeed, just to ensure a communication and continuity to workloads after been migrated. And as you probably saw, HCX is a separate solution to achieve mass migration or at least automated migration. It can of course be installed in addition to L3 or L2 VPN. Each one has its proper role and purpose:
- L3: mostly for admin purpose (HLM, SSO..)
- L2: for vMotion based migrations or VM to VM comm across Cloud.
- HCX: Automated migrations, migration types choice (cold, warm, live....), network extension and Compress/dedupe
So, coming back to your questions about DNS/HLM requirements:
If you want to initiate a vMotion based migration from your on premises vCenter to VMC, you do need a DNS properly to install HLM, as HLM is required to initiate vMotion from vCenter. Otherwise, if you do not want to set your DNS accordingly, you will need to initiate from a script/API.
This is clearly explained here: Hybrid Migration with vMotion Checklist :
[.... Hybrid Linked Mode is required to initiate migration from the vSphere Client. It is not required to initiate migration using the API or PowerCLI...]
I hope this is clear now! ![]()
Good luck!
Emmanuel