kubernetes

• namespace

• generate credentials for pfx

• full steps

• configure in jenkins

• using kubeconfig for remote cluster credential

• using ClusterRoleBinding

• pull with credentials

• Q&A

references:

• podTempate

• Jenkins Kubernetes Plugin: Running Agents In Other Clusters

• Jenkins Kubernetes Plugin: Using the plugin in your pipelines

• Create Kubernetes Service Accounts and Kubeconfigs

• Setup Jenkins Pipeline and Blue Ocean in Kubernetes

• * How to Setup Jenkins Build Agents on Kubernetes Pods

• Pull an Image from a Private Registry

• 从私有仓库拉取镜像

• How to access webSockets for Jenkins inbound agents?

namespace

namespace

$ cat << EOF | kubectl apply -f -
  ---
  apiVersion: v1
  kind: Namespace
  metadata:
    name: jenkins
EOF
namespace/jenkins created

quota

$ cat << EOF | kubectl apply -f -
  apiVersion: v1
  kind: ResourceQuota
  metadata:
    name: jenkins-quota
    namespace: jenkins
  spec:
    hard:
      requests.cpu: "16"
      requests.memory: 16Gi
      limits.cpu: "32"
      limits.memory: 32Gi
EOF
resourcequota/jenkins-quota edited

sa.yml

• jenkins.io

    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: ClusterRole
    metadata:
      name: jenkins-admin
    rules:
      - apiGroups: [""]
        resources: ["*"]
        verbs: ["*"]
    ---
    apiVersion: v1
    kind: ServiceAccount
    metadata:
      name: jenkins-admin
      namespace: devops-tools
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: ClusterRoleBinding
    metadata:
      name: jenkins-admin
    roleRef:
      apiGroup: rbac.authorization.k8s.io
      kind: ClusterRole
      name: jenkins-admin
    subjects:
    - kind: ServiceAccount
      name: jenkins-admin
      namespace: devops-tools

• or

  apiVersion: v1
  kind: ServiceAccount
  metadata:
    name: jenkins-admin
    namespace: devops-tools
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: Role
  metadata:
    name: jenkins
    namespace: devops-tools
    labels:
      "app.kubernetes.io/name": 'jenkins'
  rules:
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["create","delete","get","list","patch","update","watch"]
  - apiGroups: [""]
    resources: ["pods/exec"]
    verbs: ["create","delete","get","list","patch","update","watch"]
  - apiGroups: [""]
    resources: ["pods/log"]
    verbs: ["get","list","watch"]
  - apiGroups: [""]
    resources: ["secrets"]
    verbs: ["get"]
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: RoleBinding
  metadata:
    name: jenkins-role-binding
    namespace: devops-tools
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: Role
    name: jenkins
  subjects:
  - kind: ServiceAccount
    name: jenkins-admin
    namespace: devops-tools

• grant more permissions via RoleBinding

  apiVersion: v1
  kind: ServiceAccount
  metadata:
    name: jenkins
    namespace: devops
  ---
  kind: ClusterRole
  apiVersion: rbac.authorization.k8s.io/v1beta1
  metadata:
    name: jenkins
  rules:
    - apiGroups: ["extensions", "apps"]
      resources: ["deployments"]
      verbs: ["create", "delete", "get", "list", "watch", "patch", "update"]
    - apiGroups: [""]
      resources: ["services"]
      verbs: ["create", "delete", "get", "list", "watch", "patch", "update"]
    - apiGroups: [""]
      resources: ["pods"]
      verbs: ["create","delete","get","list","patch","update","watch"]
    - apiGroups: [""]
      resources: ["pods/exec"]
      verbs: ["create","delete","get","list","patch","update","watch"]
    - apiGroups: [""]
      resources: ["pods/log"]
      verbs: ["get","list","watch"]
    - apiGroups: [""]
      resources: ["secrets"]
      verbs: ["get"]
  ---
  apiVersion: rbac.authorization.k8s.io/v1beta1
  kind: ClusterRoleBinding
  metadata:
    name: jenkins
    namespace: devops
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: ClusterRole
    name: jenkins
  subjects:
    - kind: ServiceAccount
      name: jenkins
      namespace: devops

generate credentials for pfx

ca.crt

$ grep certificate-authority-data ~/.kube/config | awkubectl -F': ' '{print $NF}' |  base64 -d > ca.crt
# OR
$ sudo cat /etc/kubernetes/pki/ca.crt

client.crt & client.key

$ grep client-certificate-data ~/.kube/config | awkubectl -F': ' '{print $NF}' |  base64 -d > client.crt
$ grep client-key-data ~/.kube/config | awkubectl -F': ' '{print $NF}' |  base64 -d > client.key

cert.pfx

$ openssl pkcs12 -export -out cert.pfx -inkey client.key -in client.crt -certfile ca.crt
Enter Export Password:
Verifying - Enter Export Password:

$ ls
ca.crt  cert.pfx  client.crt  client.key

# or

# using password 'marslo'
$ openssl pkcs12 -export -out cert.pfx -inkey client.key -in client.crt -certfile ca.crt -password pass:marslo

full steps

$ cat ~/.kube/config \
      | grep certificate-authority-data \
      | awkubectl '{print $2}' \
      | base64 -d > ca.crt
$ cat ~/.kube/config \
      | grep client-certificate-data \
      | awkubectl '{print $2}' \
      | base64 -d > client.crt
$ cat ~/.kube/config \
      | grep client-key-data \
      | awkubectl '{print $2}' \
      | base64 -d > client.key
$ openssl pkcs12 -export \
                 -out cert.pfx \
                 -in client.crt \
                 -inkey client.key \
                 -certfile ca.crt \
                 -password pass:devops

configure in jenkins

[!NOTE]

• url

  • by default: http://<service-name>.<namespace>.svc.cluster.local:8080

• Manage Jenkins -> Configure System or Manage Jenkins -> Manage Nodes and Clouds -> Configure Clouds

• Add a new Cloud -> Kuberentes

  • Name:

  • Kubernetes URL:

    • get from $ kubectl cluster-info

    • using https://kubernetes.default.svc.cluster.local

  • Kubernetes server certificate key: content of ca.crt. ($ cat ca.crt)

  • Credentials:

    • Add -> Jenkins

    • Kind: Certificate

  

  plugin-1

  

  plugin-2

  

  plugin-3

  

  plugin-4
• setup in jenkins

  

  plugin-5

using kubeconfig for remote cluster credential

reference:

• jenkinsci/kubernetes-cli-plugin

• Kubernetes Plugin: Authenticate with a ServiceAccount to a remote cluster

• Creating a kubeconfig file for a self-hosted Kubernetes cluster

• How to find your Jenkins admin password on Kubernetes

get Kubernetes URL

$ kubectl config view --minify | sed -n -re 's/^.*server: (https.*)$/\1/p'

• or

  $ kubectl config view --minify --raw --output 'jsonpath={..cluster.server}'

generate CA

the content can be also found in kubernetes-master:/etc/kubernetes/pki/ca.crt

$ kubectl -n jenkins get secret \
              $(kubectl -n jenkins get sa jenkins-admin -o jsonpath={.secrets[0].name}) \
              -o jsonpath={.data.'ca\.crt'} \
              | base64 --decode

• or

  $ cat ~/.kube/config \
        | grep certificate-authority-data \
        | awkubectl '{print $2}' \
        | base64 -d > ca.crt

Generate token in kubernetes

$ namespace='devops'
$ serviceAccount='jenkins-admin'
$ alias k='kubectl'

• setup sa

  $ kubectl -n jenkins create sa jenkins-admin
  $ kubectl -n jenkins create rolebinding jenkins-admin-binding \
                       --clusterrole=cluster-admin \
                       --serviceaccount=devops:jenkins-admin

• get token

  $ kubectl -n jenkins \
         get sa jenkins-admin \
         -o go-template \
         --template='{{range .secrets}}{{.name}}{{"\n"}}{{end}}'
  jenkins-admin-token-kshsh
  
  $ kubectl -n jenkins \
         get secrets jenkins-admin-token-kshsh \
         -o go-template \
         --template '{{index .data "token"}}' \
         | base64 -d
  eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.***

  • more info

    $ kubectl get secret -n jenkins
    NAME                        TYPE                                  DATA   AGE
    default-token-8k7vj         kubernetes.io/service-account-token   3      27m
    jenkins-admin-token-9r8pt   kubernetes.io/service-account-token   3      21m
    
    $ kubectl -n jenkins get rolebinding
    NAME                    AGE
    jenkins-admin-binding   15m
    $ kubectl -n jenkins describe rolebinding jenkins-admin-binding
    Name:         jenkins-admin-binding
    Labels:       <none>
    Annotations:  <none>
    Role:
      Kind:  ClusterRole
      Name:  cluster-admin
    Subjects:
      Kind            Name           Namespace
      ----            ----           ---------
      ServiceAccount  jenkins-admin  jenkins
    
    $ kubectl describe clusterrolebindings jenkins-admin-cluster-binding
    Name:         jenkins-admin-cluster-binding
    Labels:       <none>
    Annotations:  <none>
    Role:
      Kind:  ClusterRole
      Name:  cluster-admin
    Subjects:
      Kind            Name           Namespace
      ----            ----           ---------
      ServiceAccount  jenkins-admin  jenkins

  • or

    $ kubectl -n jenkins \
        get secret \
        $(kubectl -n jenkins get sa jenkins-admin -o jsonpath={.secrets[0].name}) \
        -o jsonpath={.data.token} \
        | base64 --decode

  • or

    $ kubectl -n jenkins \
           get sa jenkins-admin \
           --template='{{range .secrets}}{{ .name }} {{end}}' \
           | xargs -n 1 kubectl -n jenkins get secret \
                          --template='{{ if .data.token }}{{ .data.token }}{{end}}' \
                          | head -n 1 \
                          | base64 -d -

  • or

    # sa='jenkins-admin'
    $ kubectl -n jenkins \
                 get secrets \
                 $(kubectl -n jenkins get sa ${sa} -o=jsonpath='{.secrets[0].name}') \
                 -o=jsonpath='{.data.token}' |
              base64 -d

setup in Jenkins

• credential setup

• cloud setup

using ClusterRoleBinding

references:

• Configure Service Accounts for Pods

• RoleBinding and ClusterRoleBinding

• Role and ClusterRole

• Jenkins minimal installation on Kubernetes

[!TIP] simplely it can be executed via commands:

$ kubectl -n kube-system create sa <service-account>
$ kubectl create clusterrolebinding <role-binding-name> --clusterrole cluster-admin --serviceaccount=<namespace>:<service-account>

[!NOTE]: <role-binding-name> can be the same as <service-account>

---
apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-app: jenkins
  name: jenkins-admin
  namespace: jenkins
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: jenkins-admin
  labels:
    k8s-app: jenkins
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: jenkins-admin
  namespace: jenkins

• using RoleBinding

  ---
  apiVersion: rbac.authorization.k8s.io/v1beta1
  kind: Role
  metadata:
   name: jenkins-admin
   namespace: jenkins
  rules:
  - apiGroups: [""]
   resources: ["pods"]
   verbs: ["create","delete","get","list","patch","update","watch"]
  - apiGroups: [""]
   resources: ["pods/exec"]
   verbs: ["create","delete","get","list","patch","update","watch"]
  - apiGroups: [""]
   resources: ["pods/log"]
    verbs: ["get","list","watch"]
  ---
  apiVersion: rbac.authorization.k8s.io/v1beta1
  kind: RoleBinding
  metadata:
   name: jenkins-admin
   namespace: jenkins
  roleRef:
   apiGroup: rbac.authorization.k8s.io
   kind: Role
   name: jenkins-admin
  subjects:
  - kind: ServiceAccount
   name: jenkins-admin

• or grant more permissions via RoleBinding

  apiVersion: v1
  kind: ServiceAccount
  metadata:
    name: jenkins
    namespace: devops
  ---
  kind: ClusterRole
  apiVersion: rbac.authorization.k8s.io/v1beta1
  metadata:
    name: jenkins
  rules:
    - apiGroups: ["extensions", "apps"]
      resources: ["deployments"]
      verbs: ["create", "delete", "get", "list", "watch", "patch", "update"]
    - apiGroups: [""]
      resources: ["services"]
      verbs: ["create", "delete", "get", "list", "watch", "patch", "update"]
    - apiGroups: [""]
      resources: ["pods"]
      verbs: ["create","delete","get","list","patch","update","watch"]
    - apiGroups: [""]
      resources: ["pods/exec"]
      verbs: ["create","delete","get","list","patch","update","watch"]
    - apiGroups: [""]
      resources: ["pods/log"]
      verbs: ["get","list","watch"]
    - apiGroups: [""]
      resources: ["secrets"]
      verbs: ["get"]
  ---
  apiVersion: rbac.authorization.k8s.io/v1beta1
  kind: ClusterRoleBinding
  metadata:
    name: jenkins
    namespace: devops
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: ClusterRole
    name: jenkins
  subjects:
    - kind: ServiceAccount
      name: jenkins
      namespace: devops

• or get all permission via RoleBinding

  # spinnaker-role-and-rolebinding-target.yml
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: Role
  metadata:
    name: spinnaker-role
    namespace: target                       # Should be namespace you are granting access to
  rules:
  - apiGroups: ["*"]
    resources: ["*"]
    verbs: ["*"]
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: RoleBinding
  metadata:
    name: spinnaker-rolebinding
    namespace: target                       # Should be namespace you are granting access to
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: Role
    name: spinnaker-role                    # Should match name of Role
  subjects:
  - namespace: source                       # Should match namespace where SA lives
    kind: ServiceAccount
    name: spinnaker-service-account         # Should match service account name, above

• or details rules in role binding

  apiVersion: v1
  kind: ServiceAccount
  metadata:
    name: jenkins-admin
    namespace: devops-tools
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: Role
  metadata:
    name: jenkins
    namespace: devops-tools
    labels:
      "app.kubernetes.io/name": 'jenkins'
  rules:
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["create","delete","get","list","patch","update","watch"]
  - apiGroups: [""]
    resources: ["pods/exec"]
    verbs: ["create","delete","get","list","patch","update","watch"]
  - apiGroups: [""]
    resources: ["pods/log"]
    verbs: ["get","list","watch"]
  - apiGroups: [""]
    resources: ["secrets"]
    verbs: ["get"]
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: RoleBinding
  metadata:
    name: jenkins-role-binding
    namespace: devops-tools
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: Role
    name: jenkins
  subjects:
  - kind: ServiceAccount
    name: jenkins-admin
    namespace: devops-tools

pull with credentials

[!NOTE|label:references:]

• Pull an Image from a Private Registry

• 从私有仓库拉取镜像

• 为特定名称空间创建 imagePullSecrets

• in kubernetes

  # create secrets in namespace
  
  ## via ~/.docker/config.json
  $ kubectl -n devfops create secret generic image-pull-secrets \
            --from-file=.dockerconfigjson=.docker/config.json \
            --type=kubernetes.io/dockerconfigjson
  
  ## via cmd
  $ kubectl -n devops create secret docker-registry image-pull-secrets \
            --docker-server=artifactory.example.com \
            --docker-username=devops \
            --docker-password=password \
            --docker-email=[e-mail]
  
  # check result
  $ kubectl -n devop get secret image-pull-secrets \
            -o jsonpath="{.data.\.dockerconfigjson}" |
    base64 -d

• copy secrets to all namespaces

  # copy
  $ kubectl get ns -o custom-columns=":metadata.name" --no-headers |
            xargs -t -i bash -c "echo -e \"\\n-- {} --\"; kubectl -n devops get secrets image-pull-secrets -o yaml --export | kubectl apply -n {} -f -"
  
  # check
  $ kubectl get secrets --all-namespaces  | grep image-pull-secrets

• in podTemplate

  podTemplate( cloud: 'Staging Kubernetes',
               label: env.BUILD_TAG ,
               name: env.BUILD_TAG,
               showRawYaml: true,
               namespace: 'devops',
               yaml: """
                 apiVersion: v1
                 kind: Pod
                 spec:
                   hostNetwork: true
                   nodeSelector:
                     kubernetes.io/hostname: "staging-node-1"
                   imagePullSecrets:
                   - name: "image-pull-secrets"             # secrets name here
                   containers:
                   - name: jnlp
                     image: 'artifactory.example.com/docker/sandbox:bionic'
                     workingDir: '/home/devops'
                     resources:
                       limits:
                         memory: "1024Mi"
                         cpu: "512m"
                       requests:
                         memory: "512Mi"
                         cpu: "256m"
               """
  ) { node( env.BUILD_TAG ) { container('jnlp') {
      stage('show info') {
        sh """
          id
          whoami
          echo ${WORKSPACE}
          realpath ${WORKSPACE}
        """
        println POD_CONTAINER
      }
    }}
  }

Q&A

[!NOTE]

• Kubernetes agents are failing with SocketTimeoutException: connect timed out

• Message: pods is forbidden: User "system:serviceaccount:jenkins:jenkins-admin" cannot list resource "pods" in API group solution:

  • lachie83/jenkins-service-account

  • see also

  • chukaofili/k8s-dashboard-admin-user.yaml

$ kubectl -n <namespace> create rolebinding <sa>-binding \
                                --clusterrole=cluster-admin \
                                --serviceaccount=<namespace>:<sa>
$ kubectl create clusterrolebinding jenkins-admin-cluster-binding \
                                    --clusterrole cluster-admin \
                                    --serviceaccount=<namespace>:jenkins-admin

• thinking

  $ kubectl -n jenkins auth can-i list pods --as jenkins-admin
  no
  
  $ kubectl -n jenkins auth can-i list pods --as jenkins-admin-binding
  no
  
  $ kubectl -n jenkins auth can-i list pods --as jenkins-admin-cluster-binding
  no