diff --git a/contrib/mesos/docs/discovery.md b/contrib/mesos/docs/discovery.md new file mode 100644 index 00000000000..fb9e2d66a63 --- /dev/null +++ b/contrib/mesos/docs/discovery.md @@ -0,0 +1,91 @@ +# Discovery + +## DNS + +### kube-dns + +[**kube-dns**](https://github.com/kubernetes/kubernetes/blob/release-1.1/docs/admin/dns.md) is a Kubernetes add-on that works out of the box with Kubernetes-Mesos. +For details on usage see the implementation in the `cluster/mesos/docker` source tree. +kube-dns provides records both for services and pods. + +### mesos-dns + +**NOTE:** There is still no support for publishing Kubernetes *services* in mesos-dns. + +**mesos-dns** communicates with the leading Mesos master to build a DNS record set that reflects the tasks running in a Mesos cluster as documented here: http://mesosphere.github.io/mesos-dns/docs/naming.html. +As of Kubernetes-Mesos [release v0.7.2](https://github.com/mesosphere/kubernetes/releases/tag/v0.7.2-v1.1.5) there is experimental support in the scheduler to populate a task's *discovery-info* field in order to generate alternative/more friendly record names in mesos-dns, for *pods* only. + +To enable this feature, set `--mesos-generate-task-discovery=true` when launching the scheduler. + +The following discovery-info fields may be set using labels (without a namespace prefix) or else `k8s.mesosphere.io/discovery-XXX` annotations: + +* `visibility`: may be `framework`, `external`, or `cluster` (defaults to `cluster`) +* `environment` +* `location` +* `name` (this alters record set generation in *mesos-dns*) +* `version` + +In the case where both a label as well as an annotation are supplied the value of the annotation is observed. +The interpretation of value of the `name` label (and `discovery-name` annotation) is a special case: the generated Mesos `discovery-info.name` value will be `${name}.${pod-namespace}.pod`; all other discovery-info values are passed through without modification. + +#### Example 1: Use a `name` label on a pod template +```yaml +apiVersion: v1 +kind: ReplicationController +metadata: + name: frontend +spec: + replicas: 3 + template: + metadata: + labels: + app: guestbook + tier: frontend + name: custom-name + spec: + containers: + - name: php-redis + image: gcr.io/google_samples/gb-frontend:v3 + resources: + requests: + cpu: 100m + memory: 100Mi + env: + - name: GET_HOSTS_FROM + value: dns + ports: + - containerPort: 80 +``` + +#### Example 2: Use a `discovery-name` annotation on a pod template +```yaml +apiVersion: v1 +kind: ReplicationController +metadata: + name: frontend +spec: + replicas: 3 + template: + metadata: + labels: + app: guestbook + tier: frontend + annotations: + k8s.mesosphere.io/discovery-name: custom-name + spec: + containers: + - name: php-redis + image: gcr.io/google_samples/gb-frontend:v3 + resources: + requests: + cpu: 100m + memory: 100Mi + env: + - name: GET_HOSTS_FROM + value: dns + ports: + - containerPort: 80 +``` + + +[![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/contrib/mesos/docs/discovery.md?pixel)]()