Kubernetes Registry Plugin for micro
This is a plugin for go-micro that allows you to use Kubernetes as a registry.
Overview
This registry plugin makes use of Annotations and Labels on a Kubernetes pod to build a service discovery mechanism.
RBAC
If your Kubernetes cluster has RBAC enabled, a role and role binding
will need to be created to allow this plugin to list and patch pods.
A cluster role can be used to specify the list and patch
requirements, while a role binding per namespace can be used to apply
the cluster role. The example RBAC configs below assume your Micro-based
services are running in the test namespace, and the pods that contain
the services are using the micro-services service account.
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: micro-registry
rules:
- apiGroups:
- ""
resources:
- pods
verbs:
- list
- patch
- watch
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: micro-registry
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: micro-registry
subjects:
- kind: ServiceAccount
name: micro-services
namespace: test
Gotchas
- Registering/Deregistering relies on the HOSTNAME Environment Variable, which inside a pod is the place where it can be retrieved from. (This needs improving)
Connecting to the Kubernetes API
Within a pod
If the --registry_address flag is omitted, the plugin will securely connect to
the Kubernetes API using the pods "Service Account". No extra configuration is necessary.
Find out more about service accounts here. http://kubernetes.io/docs/user-guide/accessing-the-cluster/
Outside of Kubernetes
Some functions of the plugin should work, but its not been heavily tested. Currently no TLS support.