Kubernetes plugin for drone.io

This is an adaptation from honestbee/drone-kubernetes drone plugin, which allows to execute a remote command in a container inside a pod

Usage

This pipeline will execute the command echo hello world inside the pod pod1 in the container with name my-container

steps:
    - name execute_command:
      image: contraslash/drone-kubernetes-command-in-pod
      pod_name: "pod1"
      container_name: "my-container"
      container_command: "echo hello world"
      secrets: [KUBERNETES_CLIENT_CERTIFICATE, KUBERNETES_CLIENT_KEY, KUBERNETES_SERVER]

For the usage with drone 1 +

  - name: migrate_test_new_cluster
    image: contraslash/drone-kubernetes-command-in-pod
    settings:
      pod_name: "pod1"
      container_name: "my-container"
      container_command:  "echo hello world"
      tag: "${DRONE_COMMIT_SHA:0:8}"
      KUBERNETES_CLIENT_CERTIFICATE:
        from_secret: KUBERNETES_CLIENT_CERTIFICATE
      KUBERNETES_CLIENT_KEY:
        from_secret: KUBERNETES_CLIENT_KEY
      KUBERNETES_SERVER:
       from_secret: KUBERNETES_SERVER

Required secrets

drone secret add --image=honestbee/drone-kubernetes \
    your-user/your-repo KUBERNETES_SERVER https://mykubernetesapiserver

drone secret add --image=honestbee/drone-kubernetes \
    your-user/your-repo KUBERNETES_CERT <base64 encoded CA.crt>

drone secret add --image=honestbee/drone-kubernetes \
    your-user/your-repo KUBERNETES_TOKEN eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJrdWJ...

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 )

How to get token

1. After deployment inspect you pod for name of (k8s) secret with token and ca.crt

kubectl describe po/[ your pod name ] | grep SecretName | grep token

(When you use default service account)

2. Get data from you (k8s) secret

kubectl get secret [ your default secret name ] -o yaml | egrep 'ca.crt:|token:'

3. Copy-paste contents of ca.crt into your drone's KUBERNETES_CERT secret
4. Decode base64 encoded token

echo [ your k8s base64 encoded token ] | base64 -d && echo''

5. Copy-paste decoded token into your drone's KUBERNETES_TOKEN secret

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:'

To do

Replace the current kubectl bash script with a go implementation.

Special thanks

Inspired by drone-helm.