Recently I came across an issue wherein, patching VCSA 6.7 was stuck for several hours, good that I had taken a backup, a week prior to that.

From the logs, I could observe below points

Update was staged around
2020-xx-xx INFO:vmware.appliance.vapi.auth:Authorization request for service_id: com.vmware.appliance.update.staged, operation_id: get
2020-xx-xx [2409]DEBUG:vmware.appliance.update.update_functions:/storage/core/software-update/updates directory created successfully
Header {‘buildnumber’: ‘15132721’, ‘updateversion’: True, ‘version_supported’: [”], ‘severity’: ‘Critical’, ‘summary’: ‘Patch for VMware vCenter Server Appliance 6.7.0’, ‘leaf_services’: [‘vmware-pod’], ‘category’: ‘Bugfix’, ‘size in MB’: 1888, ‘version’: ‘6.7.0.42000’, ‘kb’: ‘https://docs.vmware.com/en/VMware-vSphere/6.7/rn/vsphere-vcenter-server-67u3b-release-notes.html#full_patch&#8217;, ‘releasedate’: ‘December 5, 2019’, ‘tags’: ‘[]’, ‘name’:<name>, ‘rebootrequired’: True, ‘productname’: ‘VMware vCenter Server Appliance’, ‘vendor’: ‘VMware, Inc.’}

Around 15 mins post that, VCSA services went down around
2020-xx-xx [Thread-20 INFO com.vmware.vim.dataservices.VpxdSvcsMain opId=] Shutting down the server

Around same time, vmdird logs show
2020-xx-xx info vmdird t@139879811753728: mdb stats: last_pgno 5207, max_pgs 5242880
2020-xx-xx info vmdird t@139879811753728: VmDirShutdown shutdown backend complete.
2020-xx-xx info vmdird t@139879811753728: Lotus Vmdird: stop
2020-xx-xx info vmdird Stopping VMware Directory Service done

A minute later in the messages logs, we noticed, services started coming up
2020-xx-xx vcenter systemd[1]: Starting VMware Service Lifecycle Manager…
2020-xx-xx vcenter systemd[1]: Started VMware Service Lifecycle Manager.

Around 3 hours later, we noticed below snippet in messages logs
2020-xx-xx vcenter systemd-timesyncd[1124]: Timed out waiting for reply from 216.239.35.0:123 (time1.google.com).
2020-xx-xx vcenter systemd-timesyncd[1124]: Timed out waiting for reply from 216.239.35.4:123 (time2.google.com).
2020-xx-xx vcenter systemd-timesyncd[1124]: Timed out waiting for reply from 216.239.35.8:123 (time3.google.com).
2020-xx-xx vcenter systemd-timesyncd[1124]: Timed out waiting for reply from 216.239.35.12:123 (time4.google.com).

From the above snippets, we can deduce that VCSA was unable to connect with the configured local NTP server & hence it then tried to connect with google time servers, which failed as well & eventually the upgrade was stuck.

After configuring an external NTP Server, VCSA update was re-initiated & it was successful this time.

Hope this article helps!