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Explore cert manager

cert-manager is a native Kubernetes certificate management controller. It can help with issuing certificates from a variety of sources, such as Let’s Encrypt, HashiCorp Vault, Venafi, a simple signing key pair, or self signed.

It will ensure certificates are valid and up to date, and attempt to renew certificates at a configured time before expiry.

It is loosely based upon the work of kube-lego and has borrowed some wisdom from other similar projects such as kube-cert-manager.

cert-manager

Goals

  • Deploy a sample web app
  • Deploy ingress controller
  • Deploy cert manager
  • Use cert manager in ingress controller

HTTPs background

Workflow of https request

https-workflow

Workflow of CA signing

ca-signing-workflow

Steps

Deploy the sample web app and ingress controller

Note: Please refer to this doc for how to deploy a sample web app and ingress controller(contour) to a kind cluster

Deploy cert manager

Create CA secrete in k8s cluster

  • Generate CA key pairs
alias brew-openssl=/usr/local/Cellar/[email protected]/1.1.1f/bin/openssl

# Generate ca key
brew-openssl genrsa -out ca.key 2048

# Generate ca cert
brew-openssl req -x509 -new -nodes -key ca.key -sha256 -days 1825 -subj "/CN=local.daniel.issuer" -out ca.crt
  • Create k8s secret for the ca key pairs
kubectl create secret tls local-daniel-ca-key-pair --key=ca.key --cert=ca.crt

Create the issuer

apiVersion: cert-manager.io/v1alpha2
kind: Issuer
metadata:
  name: ca-issuer
spec:
  ca:
    secretName: local-daniel-ca-key-pair

Making cert manager work with HTTPProxy

https://projectcontour.io/guides/cert-manager/

HttpProxy currently cannot work with cert manager direclty. We have to make a detour.

  • Create HttpProxy
apiVersion: projectcontour.io/v1
kind: HTTPProxy
metadata:
  name: cowsay
spec:
  virtualhost:
    fqdn: local.daniel.io
    tls:
      secretName: local-daniel-io-cert
  routes:
    - services:
      - name: cowsay-blue
        port: 1323
      conditions:
        - prefix: /

Note: The HTTPProxy instance will under invalid status until the Ingress instance is created

  • Create Ingress
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  annotations:
    cert-manager.io/issuer: "ca-issuer"
    ingress.kubernetes.io/force-ssl-redirect: "true"
    kubernetes.io/tls-acme: "true"
  name: cowsay
spec:
  rules:
  - host: local.daniel.io
    http:
      paths:
      - backend:
          serviceName: cowsay-blue
          servicePort: 1323
  tls:
  - hosts:
    - local.daniel.io
    secretName: local-daniel-io-cert

Now, you should be able to see a secret named local-daniel-io-cert got created.

Access to the service

curl -k https://local.daniel.io/

Or access on web browser at: https://local.daniel.io/

References

https://cert-manager.io/docs/

https://projectcontour.io/guides/cert-manager/

https://cert-manager.io/docs/installation/kubernetes/

https://cert-manager.io/docs/configuration/ca/