92 lines
3.0 KiB
Markdown
92 lines
3.0 KiB
Markdown
# 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
|
|
```
|
|
|
|
|
|
[]()
|