Introduction

cert-manager provides X.509 certificate management on Kubernetes.

Setup

Install

Install cert-manager on your cluster by following the instruction in the link below.

You can use following command: kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.11.0/cert-manager.yaml

Once started you should see the following 3 pods running:

cert-manager

$ kubectl get pods -n cert-manager
NAME                                       READY   STATUS    RESTARTS   AGE
cert-manager-5b65cb968c-d2zbv              1/1     Running   0          5h46m
cert-manager-cainjector-56b88bcdf7-7gbj6   1/1     Running   0          5h46m
cert-manager-webhook-c784c79c7-6d57m       1/1     Running   0          5h46m

Create Issuer

Create a cluster-issuer and a certificate/secret for the self signed root CA

ClusterIssuer

apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: selfsigned-rootca-cluster-issuer
spec:
  selfSigned: {}
---
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: selfsigned-rootca
  namespace: default
spec:
  isCA: true
  duration: 2160h # 90d
  renewBefore: 360h # 15d
  commonName: selfsigned-rootca
  subject:
    organizations:
      - oran
    organizationalUnits:
      - oran
    countries:
      - Ireland
    localities:
      - Dublin
    streetAddresses:
      - Main Street
  secretName: cm-cluster-issuer-rootca-secret
  privateKey:
    rotationPolicy: Always
    algorithm: RSA
    encoding: PKCS1
    size: 2048
  issuerRef:
    name: selfsigned-rootca-cluster-issuer
    kind: ClusterIssuer
    group: cert-manager.io
  dnsNames:
  - localhost
  - minikube
  ipAddresses:
    - 127.0.0.1
    - 192.168.49.2
  emailAddresses:
    - ca@mail.com

Create an issuer for the self signed root CA

Issuer

apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
  name: cm-ca-issuer
  namespace: default
spec:
  ca:
    secretName: cm-cluster-issuer-rootca-secret

Create Certificate

Create a server key/certificate/keystore/truststore

server

apiVersion: v1
kind: Secret
metadata:
  name: cm-keycloak-jwk-pw
  namespace:  default
type: Opaque
data:
  password: Y2hhbmdlaXQ=
---
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: keycloak-server-cert
  namespace: default
spec:
  secretName: cm-keycloak-server-certs
  duration: 2160h # 90d
  renewBefore: 360h # 15d
  subject:
    organizations:
      - oran
    organizationalUnits:
      - oran
    countries:
      - IE
    localities:
      - Dublin
    streetAddresses:
      - Main Street
  commonName: keycloak
  isCA: false
  keystores:
    jks:
      create: true
      passwordSecretRef:
        name: cm-keycloak-jwk-pw
        key: password
  privateKey:
    algorithm: RSA
    encoding: PKCS1
    size: 2048
  usages:
    - server auth
  dnsNames:
    - keycloak.default
    - keycloak
    - keycloak.est.tech
  emailAddresses:
    - server@mail.com
  issuerRef:
    name: cm-ca-issuer
    kind: Issuer
    group: cert-manager.io

This certificate creates a secret "cm-keycloak-server-certs" containing 5 data items: tls.key (private key), tls.crt (Corresponding certificate), ca.crt (CA certificate), keystore.jks (keystore) and truststore.jks (truststore)

The keystore and truststore can be used to start keycloak over https.

Create a client key/certificate

client

apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: keycloak-client-cert
  namespace: default
spec:
  secretName: 
  duration: 2160h # 90d
  renewBefore: 360h # 15d
  subject:
    organizations:
      - oran
    organizationalUnits:
      - oran
    countries:
      - IE
    localities:
      - Dublin
    streetAddresses:
      - Main Street
  commonName: keycloak
  isCA: false
  privateKey:
    algorithm: RSA
    encoding: PKCS1
    size: 2048
  usages:
    - client auth
  dnsNames:
    - keycloak.default
    - keycloak
    - keycloak.est.tech
  emailAddresses:
    - client@mail.com
  issuerRef:
    name: cm-ca-issuer
    kind: Issuer
    group: cert-manager.io

This certificate creates a secret "cm-keycloak-client-certs" containing 3 data items: tls.key (private key), tls.crt (Corresponding certificate) and ca.crt (CA certificate)

These certs can be used to communicate with the keycloak server over https.

Note: email addresses appear in the subject's alternative name rather than the distinguished name