You can upgrade your Trove using the same cluster morphology that was used to deploy it. It's recommended to use the 'ssh-rsync' write extension, which deploys an update to a running system ready to be run when the machine is rebooted. For this, you should set the deployment type field to ssh-rsync and the location field to a hostname or address that SSH can understand.

The cluster morph for trove.baserock.org is a useful example. This cluster morph was not used for the initial deployment of trove.baserock.org; that cluster morph contained private information such as SSH private keys, so it cannot be made public. But that cluster is now used for keeping trove.baserock.org up to date.

Upgrade procedure:

Build an up to date Trove (see above).
OPTIONAL: tag your definitions repository.
```
 git tag -a trove-$YYYYMMDD -m "Trove upgrade deployed $YYYY-MM-DD
 git push origin trove-$YYYYMMDD
```
When deploying a system, Morph saves the output of git describe (which includes the name of the latest tag) in the file /baserock/deployment.meta. This provides a possible method for future upgrades to identify the system version symbolically, in case they need to do some extra steps. Nothing is currently implemented that uses this, it's merely futureproofing.
Deploy the cluster to the running system. This requires root access to the system.

For upgrades to trove.baserock.org, we use:
```
 morph deploy --upgrade trove.baserock.org-upgrade.morph gbo.VERSION_LABEL=2014-05-29
```
(with VERSION_LABEL updated to be today's date)
Reboot the system. If by some disaster the upgrade fails to boot, you will need infrastructure access to hard reset the machine, and then access the bootloader menu to choose the previous system version. You can make the previous system version the default version with system-version-manager set-default <version_label>.
Test your updated Trove. In future the system tests repo should provide a way of running automated verification against a Trove instance. For now, test the following things manually:
- systemctl status shows no errors (other than failed interface 'sit0')
- git clone of a repo works over git://, http://, and ssh:// (https:// is not in use on git.baserock.org yet)
- gitano ls shows the results that you expect.
If and when you are confident that you do not need the old system version any more, you can run system-version-manager remove <version_label> to delete it.

Configure your VM to use your new Trove

By default morph will use git.baserock.org as its Trove. You can tell morph to use your newly deployed Trove either by using the --trove-host option when you invoke morph, or by adding the following line to /src/morph.config:

trove-host = example-trove