Kubernetes Continuous Deploy Plugin

A Jenkins plugin to deploy resource configurations to a Kubernetes cluster.

It provides the following features:

Fetch the cluster credentials from the master node via SSH. You may also configure it manually.
Variable substitution for the resource configurations, allowing you to do dynamic resource deployment.
Docker login credentials management for the private Docker registry.
No need to install the kubectl tool on the Jenkins slave nodes.

Prerequisites

A Kubernetes cluster.
Kubernetes resource configurations to be deployed.

Configure the Plugin

Within the Jenkins dashboard, select a Job and then select Configure
Scroll down and click the "Add build step" dropdown
Select "Deploy to Kubernetes"
In the "Kubeconfig" dropdown, select the kubeconfig stored in Jenkins. You can click the "Add" button on the right to add new kubeconfig (Kind: Kubernetes configuration (kubeconfig)).

You can choose one of the following methods to provide the kubeconfig details:
- Enter the kubeconfig content directly
- Set the path to the kubeconfig on the Jenkins master
- Fetch the kubeconfig from a remote SSH server
Fill in the "Config Files" with the configuration file paths. Split multiple entries with comma (,). Ant glob syntax is supported for path patterns.
By checking "Enable Variable Substitution in Config", the variables (in the form of $VARIABLE or `${VARIABLE}) in the configuration files will be replaced with the values from corresponding environment variables before they are fed to the Kubernetes management API. This allows you to dynamically update the configurations according to each Jenkins task, for example, using the Jenkins build number as the image tag to be pulled.
If your Kubernetes resources being deployed need to pull images from private registry, you can click the "Docker Container Registry Credentials / Kubernetes Secrets..." button and configure all the required registry credentials.
- Kubernetes Namespace for Secret: the namespace in which the secrets will be created with the credentials configured below. By default this will be default.
- Secret Name: the name of the secret that will be generated or updated if exists. If left blank, a unique name will be generated. The name will be exposed as environment variable KUBERNETES_SECRET_NAME and you may reference it in your configuration with the "Enable Variable Substitution in Config" option turned on.
```
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: sample-k8s-deployment
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: sample-k8s-app
    spec:
      containers:
      - name: sample-k8s-app-container
        image: <username or registry URL>/<image_name>:<tag(maybe $BUILD_NUMBER)>
        ports:
        - containerPort: 8080
      imagePullSecrets:
      - name: $KUBERNETES_SECRET_NAME
```
- Docker Container Registry Credentials: add one entry for each of the required private registry. If it is DockerHub, you may left the "Docker registry URL" as blank. Add or select the "Registry credentials" with type "Username with password".
You may also prepare the Kubernetes Secrets beforehand. and reference the secret from your resource configurations directly.

Resource Types

The following resource types are supported by the plugin:

ConfigMap
Deployment
Replica Set
Replication Controller - No rolling-update support. If that's required, consider using Deployment.
Daemon Set
Pod
Job
Service
Ingress
Secret - The plugin also provides secrets configuration.

In the context of continuous integration & continuous deployment, only those resources that need to be updated regularly should be placed in Jenkins deployment. So most of the time the plugin should mainly deal with resources of type Deployment.

Pipeline Support

The kubernetes-cd plugin provides function kubernetesDeploy for Jenkins Pipeline support. You can go to the Snippet Generator page under Pipeline Syntax section in Jenkins, select "kubernetesDeploy: Deploy to Kubernetes" from the "Sample Step" dropdown, and it will provide you configuration interface for the plugin. After filling the entries and click "Generate Pipeline Script" button, you will get the sample scripts which can be used in your Pipeline definition.

kubernetesDeploy(kubeconfigId: 'kubeconfig-credentials-id',               // REQUIRED

                 configs: '<ant-glob-pattern-for-resource-config-paths>', // REQUIRED
                 enableConfigSubstitution: false,
        
                 secretNamespace: '<secret-namespace>',
                 secretName: '<secret-name>',
                 dockerCredentials: [
                        [credentialsId: '<credentials-id-for-docker-hub>'],
                        [credentialsId: '<credentials-id-for-other-private-registry>', server: '<registry-url>'],
                 ]
)

The parameters can be divided into the following groups, which you may configure as required.

Kubeconfig

The credentials ID for the kubeconfig stored in Jenkins credentials store.

Basic config for the deployments.

kubernetesDeploy(
        ...
        configs: '<ant-glob-pattern-for-resource-config-paths>',
        enableConfigSubstitution: true,
        ...
)

enableConfigSubstitution defaults to true

Docker Container Registry Credentials / Kubernetes Secrets

kubernetesDeploy(
        ...
        secretNamespace: '<secret-namespace>',
        secretName: '<secret-name>',
        dockerCredentials: [
            [credentialsId: '<credentials-id-for-docker-hub>'],
            [credentialsId: '<credentials-id-for-other-private-registry>', server: '<registry-url>'],
        ],
)

secretNamespace will be default if omitted.
A unique secretName will be generated if omitted, and you need to reference it with variable $KUBERNETES_SECRET_NAME in your resource configurations.

Kubeconfig Binding

When the kubeconfig is prepared in the Jenkins credentials store, you can utilize the Credentials Binding plugin to bind the kubeconfig contents to a variable. You can save the contents in the variable to a local file, which can be used to invoke the kubectl command (with the --kubeconfig argument).

With pipeline:

withCredentials([kubeconfigContent(credentialsId: 'acs-ssh-folder', variable: 'KUBECONFIG_CONTENT')]) {
    sh '''cat "$KUBECONFIG_CONTENT" >kubeconfig && cat kubeconfig && rm kubeconfig'''
}

Data/Telemetry

Kubernetes Continuous Deploy Plugin collects usage data and sends it to Microsoft to help improve our products and services. Read our privacy statement to learn more.

You can turn off usage data collection in Manage Jenkins -> Configure System -> Azure -> Help make Azure Jenkins plugins better by sending anonymous usage statistics to Azure Application Insights.