Installing cert-manager for TLS certificates

Install the Cert-Manager tool to obtain TLS certificates that you can use for secure HTTPS connections in Knative. For more information about enabling HTTPS connections in Knative, see Configuring HTTPS with TLS certificates.

You can use cert-manager to either manually obtain certificates, or to enable Knative for automatic certificate provisioning. Complete instructions about automatic certificate provisioning are provided in Enabling automatic TLS cert provisioning.

Regardless of if your want to manually obtain certificates, or configure Knative for automatic provisioning, you can use the follwoing steps to install cert-manager.

Before you begin

You must meet the following requirements to install cert-manager for Knative:

  • Knative Serving must be installed. For details about installing the Serving component, see the Knative installation guides.
  • You must configure your Knative cluster to use a custom domain.
  • Knative currently supports cert-manager version 0.6.1 or higher.

Downloading and installing cert-manager

Use the following steps to download, install, and configure cert-manager for your Knative cluster environment:

  1. Run the following commands to download and extract the cert-manager installation package:
   CERT_MANAGER_VERSION=0.6.1
   DOWNLOAD_URL=https://github.com/jetstack/cert-manager/archive/v${CERT_MANAGER_VERSION}.tar.gz

   wget $DOWNLOAD_URL
   tar xzf v${CERT_MANAGER_VERSION}.tar.gz

   cd cert-manager-${CERT_MANAGER_VERSION}
  1. Run the following commands to install cert-manager:

    1. Install the cert-manager CRDs:
      kubectl apply -f deploy/manifests/00-crds.yaml
    1. Run one of the following commands to install the cert-manager plugin:

      • For Knative clusters running Kubernetes version 1.13 or above:
      # If you are running cluster version 1.13 or above
      kubectl apply -f deploy/manifests/cert-manager.yaml
      • For Knative clusters running Kubernetes version 1.12 or below:
      # If you are running cluster version 1.12 or below, you must append the --validate=false flag
      kubectl apply -f deploy/manifests/cert-manager.yaml --validate=false
    2. Configure which DNS provider is used to validate the DNS-01 challenge requests.

    By default, the Let’s Encrypt is used to demonstrate how to configure cert-manager, but you can use other supported CA’s that issue certificates with the ACME protocol. However, you must use the DNS-01 challenge type to validate requests.

    Instructions about configuring cert-manager for any of the supported DNS providers are provided in DNS01 challenge providers and configuration instructions.

    Example:

    See how the Google Cloud DNS is defined as the provider: Configuring HTTPS with cert-manager and Google Cloud DNS

    1. Post-install cleanup

    Run the following commands to remove the cert-manager install packages:

    cd ../
    rm -rf cert-manager-${CERT_MANAGER_VERSION}
    rm v${CERT_MANAGER_VERSION}.tar.gz

Completing the Knative configuration for TLS support

Before you can use a TLS certificate for secure connections, you must finish configuring Knative: