KubeGen

kubegen is an utility python library on PyPI. It is use in generating kubernetes policy files. The library generate policy based on the kind specified. It provides way of generating k8s policy files on the fly during CI/CD process.

:rotating_light:

Features

• Supports creation of deployment, ingress, svc and secret policy file
• Pass json string as argument
• Dynamically bind environment variables, volumes etc.

Installation

Installation is done using the pip install command:

   $ pip install kubegen
   $ pip3 install kubegen

Usage:

Usage: kubegen [OPTIONS]

Options:
  -k, --kind TEXT  what kind of k8s policy file are you trying to create.
                   support type includes deployment, ingress and svc.

  -d, --data TEXT  Supply payload for the policy file in jsonstring format e.g
                   {"name": "app-1", "version": "v1"}

  --help           Show this message and exit.

// Generate svc policy file

kubegen -k svc -d '{"name": "test-app", "environment": "staging", "port": 8080, "service_type": "ClusterIP", "protocol": "TCP"}'

// Generate secret policy file

kubegen -k secret -d '{"version": "v1", "metadata": {"name": "test-app", "namespace": "dev", "resourceVersion": "123", "uid": "eiir-wkie", "labels": {"name": "test-app"}}, "type": "Opaque", "data": {"username": "YWRtaW4=", "password": "MWYyZDFlMmU2N2Rm"}}'

// Generate ingress policy file

kubegen -k svc -d '{"name": "test-app", "host": "test-app.io", "port": 8080, "path": "/",  "tls_secret_name": "test-app-secret", "annotations": {"kubernetes.io/ingress.class": "nginx", "nginx.ingress.kubernetes.io/ssl-redirect": "true"}}'

// Generate deployment policy file

kubegen -k deployment -d '{"version": "apps/v1", "name": "test-app", "image": "test-app:1.0.0", "port": 8080, "environment": "staging", "image_pull_secret": "test-app-secret", "environment_variables": [{"name": "keyvault_id", "value": "12345"}], "replicas": 3, "volume_mounts": [{"name": "test-volume", "mountPath": "/app/test-volume"}], "volumes": [{"name": "test-volume", "configMap": {"name": "app-configmap"}}]}'

// Generate multi-container deployment policy file

kubegen -k multi_container_deployment -d '{"version": "apps/v1", "environment": "dev", "metadata": {"name": "test-app", "namespace": "dev", "labels": {"app": "test-app", "company": "kube"}}, "affinity": {"nodeAffinity": {"requiredDuringSchedulingIgnoredDuringExecution": {"nodeSelectorTerms": [{"matchExpressions": [{"key": "disktype", "operator": "In", "values": ["ssd"]}]}]}}}, "restartPolicy": "Always", "strategy": {"type": "Recreate"}, "replicas": 2, "containers": [{"name": "webapp", "image": "app/webapp", "ports": [{"containerPort": 8080}], "imagePullPolicy": "always", "env": [{"name": "CLIENT_ID", "value": "123"}, {"name": "HOST_URL", "value": "https://is.url"}, {"name": "DB_PASSWORD", "valueFrom": {"secretKeyRef": {"name": "cloudsql-credentials", "key": "db_pass"}}}]}, {"name": "cloudsql-proxy", "image": "gcr.io/cloudsql-docker/gce-proxy:1.16", "command": ["/cloud_sql_proxy", "-instances=demo-instance=tcp:3306", "-credential_file=/secrets/cloudsql/cred.json"]}]}'

another form of usage of affinity:
"affinity": {"podAntiAffinity": {"requiredDuringSchedulingIgnoredDuringExecution": [{"labelSelector": {"matchExpressions": [{"key": "app", "operator": "In", "values": ["web"]}]}, "topologyKey": "kubernetes.io/hostname"}]}, "podAffinity": {"requiredDuringSchedulingIgnoredDuringExecution": [{"labelSelector": {"matchExpressions": [{"key": "app", "operator": "In", "values": ["redis"]}]}, "topologyKey": "kubernetes.io/hostname"}]}}

Sample multi-container yaml output

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test-app
  namespace: dev
  labels:
    app: test-app
    company: kube
    environment: dev
spec:
  replicas: 2
  template:
    spec:
      containers:
      - name: webapp
        image: app/webapp
        ports:
        - containerPort: 8080
        imagePullPolicy: always
        env:
        - name: CLIENT_ID
          value: '123'
        - name: HOST_URL
          value: https://is.url
        - name: DB_PASSWORD
          valueFrom:
            secretKeyRef:
              name: cloudsql-credentials
              key: db_pass
      - name: cloudsql-proxy
        image: gcr.io/cloudsql-docker/gce-proxy:1.16
        command:
        - /cloud_sql_proxy
        - -instances=demo-instance=tcp:3306
        - -credential_file=/secrets/cloudsql/cred.json
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: disktype
                operator: In
                values:
                - ssd
    metadata:
      labels:
        app: test-app
        company: kube
        environment: dev
  strategy:
    type: Recreate

// Generate secret policy file

kubegen -k secret -d '{"version": "v1", "metadata": {"name": "test-app", "namespace": "dev", "resourceVersion": "123", "uid": "eiir-wkie"}, "type": "Opaque", "data": {"username": "YWRtaW4=", "password": "MWYyZDFlMmU2N2Rm"}}'