VMware made a significant effort to simplify the migration process to vSphere 6.7. They did this by introducing direct upgrades from the installation media of vCenter Server Appliance from an existing vCSA and PSC Appliance 6.5 or a Windows-based vCenter Server to the new version. The tool supports vCenter Servers running version 6.0 and higher.

The upgrade process comprises two stages:

1. vCSA deployment
2. Making a copy of the configuration from the vCenter Server source

The automated upgrade process requires the Distributed Resource Scheduler (DRS) feature in the cluster, in which the source vCenter Server is installed but not set to fully automated mode.

The upgrade procedure is straightforward and guided through a simple and clear UI in which you must specify source and target network parameters in the upgrade wizard when requested.

Before you start with the update, don't forget to create a backup of an existing vCSA appliance from the vCenter Server Appliance Management Interface (VAMI).

You can't upgrade to the new major version directly from the VAMI interface of vCSA. Those upgrades are between minor versions. As you can see, on my vCSA 6.5, I only have the option to upgrade to a newer build of vCSA 6.5, not 6.7:

The upgrade itself is not an in-place upgrade. The original vCSA won't be touched. Instead, a new vCSA will be deployed, and the data will be migrated.

To perform an upgrade of vCSA 6.5 to 6.7 with an embedded PSC, the following steps are required:

1. Mount the ISO installation media of vCSA to your management station.
2. Launch the GUI installer located at CDROM:vcsa-ui-installerwin32installer.exe.
3. Select the Upgrade option.
4. The Upgrade wizard looks similar to the installation one, and only a few steps are different. After you accept the end user agreement, you need to connect to the existing vCSA and fill in the required password for vCSA itself and the ESXi host that is being managed by the current vCSA.
5. In the next steps, you need to provide a destination ESXi host or vCenter Server where the new vCSA will be deployed. You also need to provide the new vCSA VM name and root password.
6. After you have selected the deployment size based on your inventory size and datastore, which will be used to host new vCSAs, you need to specify networking of the new vCSA. Keep in mind that you need to assign a different IP address to the new vCSA that will be used during migration. Once the migration is done, the IP will be changed to the original one.
7. Once stage 1 is complete, stage 2 configuration (the actual migration) will start.
8. Stage 2 is slightly different from the new vCSA installation. First, the pre-check is performed, and you will see the output of the pre-check in the wizard.
9. Once you resolve the warnings from the pre-check, you can select what data you need to migrate to the new vCSA. This decision will significantly affect the overall duration of the migration.
10. Once all the information is gathered, you can double-check everything before you start with the actual upgrade.
11. In the last step, you need to confirm that the original vCSA will be shut down during the process. Once the data is migrated, the old vCSA will be powered off, and a new one will get an original IP address.
12. Once the whole procedure has finished, you can see different messages based on your vSphere infrastructure and its configuration.
13. After the process has completed, you can log in to the VAMI interface of the vCSA (at the original IP address or FQDN), and you should see that the new version is running.

Now, if you log in to the vSphere client (HTML5 or Flex), you will see that the new VM has been deployed that hosts vCSA 6.7, but you will also see that the old VM is still available but powered off, as shown in the following screenshot: