By design, the Magento Cloud solution eases the way for upgrading any particular environment. However, some precautions need to be taken in case the upgrading results are not as the owner and/or administrator expected.
Step 1: Check environment health
Before starting any upgrade process, the owner/administrator must check the current status of the environment to be upgraded. This will discard any issue related to the upgrade process.
Step 2: Take snapshot
The easiest way to create a snapshot is by going to the Cloud Interface, then selecting the Master environment and finally clicking on snapshots.
By doing this, the snapshot will save the current state for all environments/branches. Note: depending on the package, besides the Master environment, some other environment might allow taking snapshots.
Another way to take a snapshot is by executing the magento cloud CLI mgc snapshot:create.
$ mgc snapshot:create
Step 3: Database backup
The fastest way to backup the database is by executing the by executing the magento cloud CLI mgc db:dump, this command will automatically download the database content of the selected environment.
$ mgc db:dump
Although, the upgrading process is very simple; by following these simple recommendations, the upgrading process might have more resources for troubleshooting in case of dealing with unexpected setbacks.