Kubernetes plugin for drone.io

Docker Repository on Docker Cloud

Borrowed and distilled from honestbee/drone-kubernetes

This plugin allows to update a Kubernetes deployment.

• Cert based auth for tls
• token based auth
• Insecure auth without tls

Usage

This pipeline will update the all containers of [kubernetes-deployements, ...] deployment with the image tagged ${DRONE_REPO_BRANCH}-${DRONE_COMMIT_SHA}

pipeline:
  deploy:
    image: razorpay/drone-kubernetes
    pull: true
    kind: [ deployment | daemonset ] // required going forward, defaults to deployment
    secrets:
      - docker_username
      - docker_password
      - server_url_<cluster>
      - server_cert_<cluster>
      - client_cert_<cluster> / - server_token_<cluster>
      - client_key_<cluster> / - server_token_<cluster>
      - ...
    user: <kubernetes-user with a cluster-rolebinding>
    cluster: <kubernetes-cluster>
    auth_mode: [ token | client-cert ] // provide only if providing server_cert_<cluster>
    deployment: [<kubernetes-deployements, ...>]
    repo: <org/repo>
    namespace: <kubernetes-namespace>
    tag:
      - ${DRONE_REPO_BRANCH}-${DRONE_COMMIT_SHA}
      - ...
    when:
      environment: <kubernetes-cluster>
      branch: [ <branches>,... ]
      event:
        exclude: [push, pull_request, tag]
        include: [deployment]

Required secrets

• server_url
• token:
  • server_token
    • kubectl get secret [ your default secret name ] -o yaml | egrep 'token:' > server.token
• tls:
  • server_cert
    • kubectl get secret [ your default secret name ] -o yaml | egrep 'ca.crt:' > ca.crt
    • kubectl get secret [ your default secret name ] -o yaml | egrep 'ca.key:' > ca.key
  • client_cert
  • client_key

    • openssl genrsa -out client.key
      openssl req -new -key client.key -out client.csr -subj "/CN=drone/O=org"
      openssl x509 -req -in client.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out client.crt -days 500
      

    • cat ca.crt | base64 > car.crt.enc
      cat client.crt | base64 > client.crt.enc
      cat client.key | base64 > client.key.enc
      

    • drone secret add -repository razorpay/gimli -image razorpay/drone-kubernetes -event deployment -name server_url_<cluster> -value https://k8s.org.com.:443
      drone secret add -repository razorpay/gimli -image razorpay/drone-kubernetes -event deployment -name server_cert_<cluster> -value @./ca.crt.enc
      drone secret add -repository razorpay/gimli -image razorpay/drone-kubernetes -event deployment -name client_cert_<cluster> -value @./client.crt.enc
      drone secret add -repository razorpay/gimli -image razorpay/drone-kubernetes -event deployment -name client_key_<cluster> -value @./client.key.enc
      

When using TLS Verification, ensure Server Certificate used by kubernetes API server is signed for SERVER url ( could be a reason for failures if using aliases of kubernetes cluster )

RBAC

When using a version of kubernetes with RBAC (role-based access control) enabled, you will not be able to use the default service account, since it does not have access to update deployments. Instead, you will need to create a custom service account with the appropriate permissions (Role and RoleBinding, or ClusterRole and ClusterRoleBinding if you need access across namespaces using the same service account).

As an example (for the web namespace):

apiVersion: v1
kind: ServiceAccount
metadata:
  name: drone-deploy
  namespace: web

---

apiVersion: rbac.authorization.k8s.io/v1beta1
kind: Role
metadata:
  name: drone-deploy
  namespace: web
rules:
  - apiGroups: ["extensions"]
    resources: ["deployments"]
    verbs: ["get","list","patch","update"]

---

apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
  name: drone-deploy
  namespace: web
subjects:
  - kind: ServiceAccount
    name: drone-deploy
    namespace: web
roleRef:
  kind: Role
  name: drone-deploy
  apiGroup: rbac.authorization.k8s.io

Once the service account is created, you can extract the ca.cert and token parameters as mentioned for the default service account above:

kubectl -n web get secrets
# Substitute XXXXX below with the correct one from the above command
kubectl -n web get secret/drone-deploy-token-XXXXX -o yaml | egrep 'ca.crt:|token:'

Local testing

With the docker-compose.yaml file, a default run of the plugin can be made. Use the build flag to rebuild the image of the plugin. Run with docker-compose up.

To do

Replace the current kubectl bash script with a go implementation.

Special thanks

Inspired by drone-helm.