The process of merging a change starts with proposing a change to be merged. Primarily, Zuul supports Gerrit as a triggering system, as well as a facility for triggering jobs based on a timer. Zuul's design is modular, so alternate triggering and reporting systems can be supported.
Zuul works with standard versions of Gerrit by invoking the
gerrit stream-events command over an SSH connection. It also reports back to Gerrit using SSH.
Zuul will need access to a Gerrit user. Consider naming the user Jenkins so that developers see that feedback from changes is from Jenkins (Zuul attempts to stay out of the way of developers, most shouldn't even need to know it's there).
Create an SSH keypair for Zuul to use if there isn't one already, and create a Gerrit user with that key:
cat ~/id_rsa.pub | ssh -p29418 gerrit.example.com gerrit create-account --ssh-key - --full-name Jenkins jenkins
Give that user whatever permissions will be needed on the projects you want Zuul to gate. For instance, you may want to grant
Verified +/-1 and
Submit to the user. Additional categories or values may be added to Gerrit. Zuul is very flexible and can take advantage of those.
A simple timer trigger is available as well. It supports triggering jobs in a pipeline based on cron-style time instructions.