Installation

Install Zuul

To install a Zuul release from PyPI, run:

pip install zuul

Or from a git checkout, run:

pip install .

That will also install Zuul’s python dependencies. To minimize interaction with other python packages installed on a system, you may wish to install Zuul within a Python virtualenv.

Zuul has several system-level dependencies as well. You can find a list of operating system packages in bindep.txt in Zuul’s source directory.

External Dependencies

Zuul interacts with several other systems described below.

Gearman

Gearman is a job distribution system that Zuul uses to communicate with its distributed components. The Zuul scheduler distributes work to Zuul mergers and executors using Gearman. You may supply your own gearman server, but the Zuul scheduler includes a built-in server which is recommended. Ensure that all Zuul hosts can communicate with the gearman server.

Zuul distributes secrets to executors via gearman, so be sure to secure it with TLS and certificate authentication. Obtain (or generate) a certificate for both the server and the clients (they may use the same certificate or have individual certificates). They must be signed by a CA, but it can be your own CA.

Nodepool

In order to run all but the simplest jobs, Zuul uses a companion program, Nodepool, to supply the nodes (whether dynamic cloud instances or static hardware) used by jobs. Before starting Zuul, ensure you have Nodepool installed and any images you require built. Zuul only makes one requirement of these nodes: that it be able to log in given a username and ssh private key.

Nodepool uses Zookeeper to communicate internally among its components, and also to communicate with Zuul. You can run a simple single-node Zookeeper instance, or a multi-node cluster. Ensure that the host running the Zuul scheduler has access to the cluster.

Ansible

Zuul uses Ansible to run jobs. Each version of Zuul is designed to work with a specific, contemporary version of Ansible. Zuul specifies that version of Ansible in its python package metadata, and normally the correct version will be installed automatically with Zuul. Because of the close integration of Zuul and Ansible, attempting to use other versions of Ansible with Zuul is not recommended.