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All about Deployment

Veriviz utilizes UNC Cloud Apps to host and deploy the service. UNC Cloud Apps runs on OKD (OpenShift Kubernetes Distribution).

What is Kubernetes?

On a high level, Kubernetes is a service that allows your application to be run in a virtual environment with its own operating system. You can think of it as what a container is to Docker on your local machine — that's essentially what a pod is on a Kubernetes deployment. This is defined by a Dockerfile in your project which OKD uses to create your pod, and in which your code is processed and run.

How does deploying on Kubernetes work

The OKD Deployment process works as follows:

  1. Being notified of CI successfully passing all tests on main and receiving a webhook callback
  2. A BuildConfig begins a new Build by pulling the repository and building a Docker image
  3. The Docker image is pushed to an ImageStream
  4. The ImageStream notifies a Deployment that a new image is available
  5. The Deployment spins up a new Pod (Container) based on the image
  6. Once the new Pod is available, it turns off the old Pod running the previous version

Credit to Kris Jordan and his website for this information

Continuous Integration, Continuous Deployment

CI/CD (Continuous Integration/Continuous Deployment) refers to the automated process of redeploying a service when new changes are made.

  • Continuous Integration refers to the process of verifying tests are passed before deployment. So for example, after a commit to main is made, tests you write will be automatically run on your new code. If these tests pass, great! They will now be handed over to continuous deployment; if not, your project will not be redeployed and you will have to iterate on your code until they pass.

  • The second step of CI/CD is Continuous Deployment. This refers to the process of automatically redeploying your service to reflect the changes you made to it. In a full CI/CD pipeline, once your project has passed the tests, it is then deployed.

In Veriviz, Continuous Integration is NOT used. This means once new changes are reflected in the main branch, it will be redeployed to OKD, rebuilt, and up and running. There are no tests to verify your work. This can be added in the future but is not necessarily needed. Don’t worry, if your code results in a failed deployment, OKD will revert to the last built pod and the service will still run on the old code. Keep in mind, bugs that do not result in a failed deployment will still be there.