Deployment and configuration management


Service management usually involves a deployment or configuration management step where updates to the service are made "live" to users. This page discusses relavent standards from the Technical Design Authority (TDA) related to the deployment or configuration of services.

This page uses technical terminology and is intended for those deploying or developing services.

Deployment and configuration of services should be:

  • Automated Deployments should not involve manual changes made to configuration or manual updates to servers.
  • Repeatable It should be possible to spin up a parallel environment at relatively short notice. This is useful both for testing and disaster recovery. Avoid making "production" an environment which cannot be re-created from scratch if necessary.
  • Documented Configuration of a service away from "defaults" should be explained and justified in accompanying documentation. In particular, any configuration steps which are not automated should be accompanied by a justification as to why they are required to be so.
  • Idempotent Automated deployment processes should make no unnecessary changes. Re-deploying the same release to an environment should result in no change.
  • Versioned Configuration and documentation related to deployment must be kept in a version control system. This naturally encourages an infrastructure as code model. It is recommended that the University Developers' Hub be used to version deployment configuration.

The Technical Design Authority (TDA) recognises that technical requirements surrounding deployment can have a long tail with some services requiring vendor-specific tooling. This page provides generic guidance for cases where it is technically feasible to choose one's deployment and configuration tooling.

This section discusses recommended tools for various scenarios.


If you feel there is a scenario which is not included, the TDA would welcome examples of best practice within UIS which could be added to this page.

Virtual machines

The TDA recommends the use of Ansible for the provisioning and on-going configuration management of virtual machines providing services within UIS. It can be run under Linux, Mac OS X and WSL2 on Windows.

Ansible has the following desirable properties:

  • It can configure both Unix-like systems and Microsoft Windows. It includes its own declarative language to describe system configuration which can be versioned.
  • It makes minimal changes; if the target system is already configured it makes no changes.
  • It is well-established within UIS and expertise exists in many groups.

Some common things to check with your Ansible configuration:

  • Running ansible-playbook with --check succeeds.
  • Running ansible-playbook with --check reports no changes if the service is up to date.
  • Ansible tasks should not report unnecessary changes in either check-mode or when actually run.
  • Removing a task from a playbook does not automatically "undo" it on the target server. You should replace a positive constraint with a negative one. For example: do not remove a "user abc123 must exist" constraint without adding a "user abc123 must not exist" one to replace it.
  • Your playbook is "lint-clean" when checked with a linting tool. The TDA does not mandate a particular linter but ansible-lint is used by some groups within UIS to keep their playbooks clean.

You should ensure that your playbooks remain clean by running a lint tool as part of a Continuous Integration process.

Cloud and on-premises infrastructure

The TDA recommends Terraform for infrastructure management. Terraform supports the following clouds:

Terraform supports a great deal of additional infrastructure options by means of multiple providers.


The API gateway service is managed using Terraform and a terraform provider for the API gateway product providing the service.

Terraform's configuration language is declarative meaning that one describes what the desired infrastructure should look like and terraform makes the required changes to make it so. As such it is naturally repeatable, automated and idempotent. Terraform configurations may be versioned and documented in the University Developers' Hub.

The terraform command-line tool comes with an opinionated formatter and syntax checker known as terraform fmt. The TDA strongly recommends that terraform fmt be run as part of a Continuous Integration process.

As Terraform is an automated tool, it can be used as part of a Continuous Deployment process to ensure that the master branch of a git repository reflects the currently deployed infrastructure.