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update the hazelcast example to API version v1beta3 #7728

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May 4, 2015
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update the hazelcast example to API version v1beta3 #7728

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135 changes: 80 additions & 55 deletions examples/hazelcast/README.md
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Expand Up @@ -23,27 +23,28 @@ Source is freely available at:
In Kubernetes, the atomic unit of an application is a [_Pod_](http://docs.k8s.io/pods.md). A Pod is one or more containers that _must_ be scheduled onto the same host. All containers in a pod share a network namespace, and may optionally share mounted volumes. In this simple case, we define a single container running Hazelcast for our pod:

```yaml
id: hazelcast
apiVersion: v1beta3
kind: Pod
apiVersion: v1beta1
desiredState:
manifest:
version: v1beta1
id: hazelcast
containers:
- name: hazelcast
image: pires/hazelcast-k8s
cpu: 1000
ports:
- name: hazelcast
containerPort: 5701
labels:
metadata:
labels:
name: hazelcast
name: hazelcast
spec:
containers:
- image: pires/hazelcast-k8s
name: hazelcast
ports:
- containerPort: 5701
name: hazelcast
protocol: TCP
resources:
limits:
cpu: "1"
```

There are a few things to note in this description. First is that we are running the ```pires/hazelcast-k8s``` image. This is a standard Ubuntu 14.04 installation with Java 8. However it also adds a custom [```application ```](https://github.com/pires/hazelcast-kubernetes-bootstrapper) that finds any Hazelcast nodes in the cluster and bootstraps an Hazelcast instance. The ```HazelcastDiscoveryController``` discovers the Kubernetes API Server using the built in Kubernetes discovery service, and then uses the Kubernetes API to find new nodes (more on this later).

You may also note that we tell Kubernetes that the container exposes the ```Hazelcast``` port. Finally, we tell the cluster manager that we need 1000 milli-cpus (1 core).
You may also note that we tell Kubernetes that the container exposes the ```hazelcast``` port. Finally, we tell the cluster manager that we need 1 cpu core.

Given this configuration, we can create the pod as follows:

Expand All @@ -55,8 +56,10 @@ After a few moments, you should be able to see the pod running:

```sh
$ kubectl get pods hazelcast
POD CONTAINER(S) IMAGE(S) HOST LABELS STATUS
hazelcast hazelcast pires/hazelcast-k8s kubernetes-minion-1/1.2.3.4 name=hazelcast Running

POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS CREATED MESSAGE
hazelcast 10.245.2.68 e2e-test-minion-vj7k/104.197.8.214 name=hazelcast Running 11 seconds
hazelcast pires/hazelcast-k8s Running 1 seconds
```


Expand All @@ -65,16 +68,21 @@ In Kubernetes a _Service_ describes a set of Pods that perform the same task. F

Here is the service description:
```yaml
id: hazelcast
apiVersion: v1beta3
kind: Service
apiVersion: v1beta1
port: 5701
containerPort: 5701
selector:
metadata:
labels:
name: hazelcast
name: hazelcast
spec:
ports:
- port: 5701
targetPort: 5701
selector:
name: hazelcast
```

The important thing to note here is the ```selector```. It is a query over labels, that identifies the set of _Pods_ contained by the _Service_. In this case the selector is ```name=hazelcast```. If you look back at the Pod specification above, you'll see that the pod has the corresponding label, so it will be selected for membership in this Service.
The important thing to note here is the ```selector```. It is a query over labels, that identifies the set of _Pods_ contained by the _Service_. In this case the selector is ```name: hazelcast```. If you look back at the Pod specification above, you'll see that the pod has the corresponding label, so it will be selected for membership in this Service.

Create this service as follows:
```sh
Expand All @@ -84,16 +92,29 @@ $ kubectl create -f hazelcast-service.yaml
Once the service is created, you can query it's endpoints:
```sh
$ kubectl get endpoints hazelcast -o yaml
apiVersion: v1beta1
creationTimestamp: 2015-01-05T05:51:50Z
endpoints:
- xxx.xxx.xxx.xxx:5701
id: hazelcast
apiVersion: v1beta3
kind: Endpoints
namespace: default
resourceVersion: 69130
selfLink: /api/v1beta1/endpoints/hazelcast?namespace=default
uid: f1937b47-949e-11e4-8a8b-42010af0e23e
metadata:
creationTimestamp: 2015-05-04T17:43:40Z
labels:
name: hazelcast
name: hazelcast
namespace: default
resourceVersion: "120480"
selfLink: /api/v1beta3/namespaces/default/endpoints/hazelcast
uid: 19a22aa9-f285-11e4-b38f-42010af0bbf9
subsets:
- addresses:
- IP: 10.245.2.68
targetRef:
kind: Pod
name: hazelcast
namespace: default
resourceVersion: "120479"
uid: d7238173-f283-11e4-b38f-42010af0bbf9
ports:
- port: 5701
protocol: TCP
```

You can see that the _Service_ has found the pod we created in step one.
Expand All @@ -106,31 +127,33 @@ In Kubernetes a _Replication Controller_ is responsible for replicating sets of
Replication Controllers will "adopt" existing pods that match their selector query, so let's create a Replication Controller with a single replica to adopt our existing Hazelcast Pod.

```yaml
id: hazelcast
apiVersion: v1beta3
kind: ReplicationController
apiVersion: v1beta1
desiredState:
metadata:
labels:
name: hazelcast
name: hazelcast
spec:
replicas: 1
replicaSelector:
selector:
name: hazelcast
# This is identical to the pod config above
podTemplate:
desiredState:
manifest:
version: v1beta1
id: hazelcast
containers:
- name: hazelcast
image: pires/hazelcast-k8s
cpu: 1000
ports:
- name: hazelcast
containerPort: 5701
labels:
name: hazelcast
template:
metadata:
labels:
name: hazelcast
spec:
containers:
- resources:
limits:
cpu: 1
image: pires/hazelcast-k8s
name: hazelcast
ports:
- containerPort: 5701
name: hazelcast
```

The bulk of the replication controller config is actually identical to the Hazelcast pod declaration above, it simply gives the controller a recipe to use when creating new pods. The other parts are the ```replicaSelector``` which contains the controller's selector query, and the ```replicas``` parameter which specifies the desired number of replicas, in this case 1.
The bulk of the replication controller config is actually identical to the Hazelcast pod declaration above, it simply gives the controller a recipe to use when creating new pods. The other parts are the ```selector``` which contains the controller's selector query, and the ```replicas``` parameter which specifies the desired number of replicas, in this case 1.

Create this controller:

Expand All @@ -149,9 +172,11 @@ Now if you list the pods in your cluster, you should see two hazelcast pods:

```sh
$ kubectl get pods
POD CONTAINER(S) IMAGE(S) HOST LABELS STATUS
hazelcast hazelcast pires/hazelcast-k8s kubernetes-minion-1.c.my-cloud-code.internal/1.2.3.4 name=hazelcast Running
16b2beab-94a1-11e4-8a8b-42010af0e23e hazelcast pires/hazelcast-k8s kubernetes-minion-3.c.my-cloud-code.internal/2.3.4.5 name=hazelcast Running
POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS CREATED MESSAGE
hazelcast 10.245.2.68 e2e-test-minion-vj7k/104.197.8.214 name=hazelcast Running 14 seconds
hazelcast pires/hazelcast-k8s Running 2 seconds
hazelcast-ulkws 10.245.1.80 e2e-test-minion-2x1f/146.148.62.37 name=hazelcast Running 7 seconds
hazelcast pires/hazelcast-k8s Running 6 seconds
```

Notice that one of the pods has the human readable name ```hazelcast``` that you specified in your config before, and one has a random string, since it was named by the replication controller.
Expand Down
39 changes: 21 additions & 18 deletions examples/hazelcast/hazelcast-controller.yaml
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@@ -1,21 +1,24 @@
id: hazelcast
apiVersion: v1beta3
kind: ReplicationController
apiVersion: v1beta1
desiredState:
metadata:
labels:
name: hazelcast
name: hazelcast
spec:
replicas: 1
replicaSelector:
selector:
name: hazelcast
podTemplate:
desiredState:
manifest:
version: v1beta1
id: hazelcast
containers:
- name: hazelcast
image: pires/hazelcast-k8s
cpu: 1000
ports:
- name: hazelcast
containerPort: 5701
labels:
name: hazelcast
template:
metadata:
labels:
name: hazelcast
spec:
containers:
- resources:
limits:
cpu: 1
image: pires/hazelcast-k8s
name: hazelcast
ports:
- containerPort: 5701
name: hazelcast
15 changes: 10 additions & 5 deletions examples/hazelcast/hazelcast-service.yaml
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@@ -1,7 +1,12 @@
id: hazelcast
apiVersion: v1beta3
kind: Service
apiVersion: v1beta1
port: 5701
containerPort: 5701
selector:
metadata:
labels:
name: hazelcast
name: hazelcast
spec:
ports:
- port: 5701
targetPort: 5701
selector:
name: hazelcast
29 changes: 15 additions & 14 deletions examples/hazelcast/hazelcast.yaml
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@@ -1,16 +1,17 @@
id: hazelcast
apiVersion: v1beta3
kind: Pod
apiVersion: v1beta1
desiredState:
manifest:
version: v1beta1
id: hazelcast
containers:
- name: hazelcast
image: pires/hazelcast-k8s
cpu: 1000
ports:
- name: hazelcast
containerPort: 5701
labels:
metadata:
labels:
name: hazelcast
name: hazelcast
spec:
containers:
- image: pires/hazelcast-k8s
name: hazelcast
ports:
- containerPort: 5701
name: hazelcast
protocol: TCP
resources:
limits:
cpu: "1"
60 changes: 0 additions & 60 deletions examples/hazelcast/v1beta3/README.md
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25 changes: 0 additions & 25 deletions examples/hazelcast/v1beta3/hazelcast-controller.yaml
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12 changes: 0 additions & 12 deletions examples/hazelcast/v1beta3/hazelcast-service.yaml
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