Assigning the vSAN License

You must assign the vSAN license to the vSAN cluster before the 60-day evaluation period expires.

By using the vSAN Management API, you can automate the license assignment on the vSAN clusters in your environment. This way, you can handle license upgrades and renewal more efficiently.
if args.vsanlicense:
    print 'Assign VSAN license'
lm = si.content.licenseManager
lam = lm.licenseAssignmentManager
lam.UpdateAssignedLicense(entity=cluster._moId, licenseKey=args.vsanlicense)