cert-manager is already installed! You installed cert-manager during setup when you used Helm to install jetstack/cert-manager. You also created an Issuer resource when you applied the file cert-manager/issuer.yaml to your cluster.
An Issuer is a cert-manager custom Kubernetes resource. It tells cert-manager how to connect to a particular CA. cert-manager will obtain certificates from a variety of Issuers, both popular public Issuers as well as private Issuers.
To use HTTPS we still need to define and deploy a Certificate resource to our cluster. We'll do that in the next step!
- Already installed in the Setup phase.