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Merge pull request kubernetes#1828 from thockin/guestbook
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Update guestbook-go.
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thockin committed Oct 17, 2014
2 parents a1dc200 + e203191 commit b011263
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118 changes: 73 additions & 45 deletions examples/guestbook-go/README.md
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Expand Up @@ -17,24 +17,23 @@ $ hack/dev-build-and-up.sh

Use the file `examples/guestbook-go/redis-master-pod.json` which describes a single pod running a redis key-value server in a container.

Create the redis pod in your Kubernetes cluster using the `kubecfg` CLI:
Create the redis pod in your Kubernetes cluster using the `kubectl` CLI:

```shell
$ cluster/kubecfg.sh -c examples/guestbook-go/redis-master-pod.json create pods
$ cluster/kubectl.sh create -f examples/guestbook-go/redis-master-pod.json
```

Once that's up you can list the pods in the cluster, to verify that the master is running:

```shell
$ cluster/kubecfg.sh list pods
$ cluster/kubectl.sh get pods
```

You'll see a single redis master pod. It will also display the machine that the pod is running on once it gets placed (may take up to thirty seconds).

```
ID Image(s) Host Labels Status
---------- ---------- ---------- ---------- ----------
redis-master-pod gurpartap/redis kubernetes-minion-3.c.briandpe-api.internal name=redis,role=master Running
ID IMAGE(S) HOST LABELS STATUS
redis-master-pod gurpartap/redis kubernetes-minion-3.c.thockin-dev.internal/86.75.30.9 name=redis,role=master Waiting
```

If you ssh to that machine, you can run `docker ps` to see the actual pod:
Expand All @@ -45,7 +44,7 @@ $ sudo docker ps

me@kubernetes-minion-3:~$ sudo docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS
e443647cd064 gurpartap/redis:latest redis-server /etc/r 22 minutes ago Up 22 minutes
e443647cd064 gurpartap/redis:latest redis-server /etc/r 2 minutes ago Up 2 minutes
```

(Note that initial `docker pull` may take a few minutes, depending on network conditions.)
Expand All @@ -55,16 +54,17 @@ A Kubernetes 'service' is a named load balancer that proxies traffic to one or m

The pod that you created in Step One has the label `name=redis` and `role=master`. The selector field of the service determines which pods will receive the traffic sent to the service. Use the file `examples/guestbook-go/redis-master-service.json`

To create the service with the `kubecfg` cli:
To create the service with the `kubectl` cli:

```shell
$ cluster/kubecfg.sh -c examples/guestbook-go/redis-master-service.json create services
ID Labels Selector Port
---------- ---------- ---------- ----------
redis-master name=redis,role=master 6379
$ cluster/kubectl.sh create -f examples/guestbook-go/redis-master-service.json

$ cluster/kubectl.sh get services
ID LABELS SELECTOR PORT
redis-master name=redis,role=master 6379
```

This will cause all pods to see the redis master apparently running on localhost:6379.
This will cause all new pods to see the redis master apparently running on $REDIS_MASTER_SERVICE_HOST at port 6379.

Once created, the service proxy on each minion is configured to set up a proxy on the specified port (in this case port 6379).

Expand All @@ -76,10 +76,11 @@ Use the file `examples/guestbook-go/redis-slave-controller.json`
to create the replication controller by running:

```shell
$ cluster/kubecfg.sh -c examples/guestbook-go/redis-slave-controller.json create replicationControllers
ID Image(s) Selector Replicas
---------- ---------- ---------- ----------
redis-slave-controller gurpartap/redis name=redis,role=slave 2
$ cluster/kubectl.sh create -f examples/guestbook-go/redis-slave-controller.json

$ cluster/kubectl.sh get replicationControllers
ID IMAGE(S) SELECTOR REPLICAS
redis-slave-controller gurpartap/redis name=redis,role=slave 2
```

The redis slave configures itself by looking for the Kubernetes service environment variables in the container environment. In particular, the redis slave is started with the following command:
Expand All @@ -91,12 +92,11 @@ redis-server --slaveof $REDIS_MASTER_SERVICE_HOST $REDIS_MASTER_SERVICE_PORT
Once that's up you can list the pods in the cluster, to verify that the master and slaves are running:

```shell
$ cluster/kubecfg.sh list pods
ID Image(s) Host Labels Status
---------- ---------- ---------- ---------- ----------
redis-master-pod gurpartap/redis kubernetes-minion-3.c.briandpe-api.internal name=redis,role=master Running
4d65822107fcfd52 gurpartap/redis kubernetes-minion-3.c.briandpe-api.internal name=redis,role=slave,replicationController=redis-slave-controller Running
78629a0f5f3f164f gurpartap/redis kubernetes-minion-4.c.briandpe-api.internal name=redis,role=slave,replicationController=redis-slave-controller Running
$ cluster/kubectl.sh get pods
ID IMAGE(S) HOST LABELS STATUS
redis-master-pod gurpartap/redis kubernetes-minion-1.c.thockin-dev.internal/86.75.30.9 name=redis,role=master Running
1472fd26-54d6-11e4-90fd-42010af00690 gurpartap/redis kubernetes-minion-4.c.thockin-dev.internal/12.34.56.78 name=redis,replicationController=redis-slave-controller,role=slave Running
1473363e-54d6-11e4-90fd-42010af00690 gurpartap/redis kubernetes-minion-3.c.thockin-dev.internal/9.3.19.76 name=redis,replicationController=redis-slave-controller,role=slave Running
```

You will see a single redis master pod and two redis slave pods.
Expand All @@ -105,15 +105,17 @@ You will see a single redis master pod and two redis slave pods.

Just like the master, we want to have a service to proxy connections to the read slaves. In this case, in addition to discovery, the slave service provides transparent load balancing to clients. The service specification for the slaves is in `examples/guestbook-go/redis-slave-service.json`

This time the selector for the service is `name=redis,role=slave`, because that identifies the pods running redis slaves. It may also be helpful to set labels on your service itself--as we've done here--to make it easy to locate them with the `kubecfg -l "label=value" list services` command.
This time the selector for the service is `name=redis,role=slave`, because that identifies the pods running redis slaves. It may also be helpful to set labels on your service itself--as we've done here--to make it easy to locate them later.

Now that you have created the service specification, create it in your cluster with the `kubecfg` CLI:
Now that you have created the service specification, create it in your cluster with the `kubectl` CLI:

```shell
$ cluster/kubecfg.sh -c examples/guestbook-go/redis-slave-service.json create services
ID Labels Selector Port
---------- ---------- ---------- ----------
redis-slave name=redis-slave name=redis,role=slave 6379
$ cluster/kubectl.sh create -f examples/guestbook-go/redis-slave-service.json

$ cluster/kubectl.sh get services
ID LABELS SELECTOR PORT
redis-master name=redis,role=master 6379
redis-slave name=redis,role=slave name=redis,role=slave 6379
```

### Step Five: Create the guestbook pod.
Expand All @@ -125,32 +127,58 @@ The pod is described in the file `examples/guestbook-go/guestbook-controller.jso
Using this file, you can turn up your guestbook with:

```shell
$ cluster/kubecfg.sh -c examples/guestbook-go/guestbook-controller.json create replicationControllers
ID Image(s) Selector Replicas
---------- ---------- ---------- ----------
guestbook-controller gurpartap/redis name=guestbook 3
$ cluster/kubectl.sh create -f examples/guestbook-go/guestbook-controller.json

$ cluster/kubectl.sh get replicationControllers
ID IMAGE(S) SELECTOR REPLICAS
redis-slave-controller gurpartap/redis name=redis,role=slave 2
guestbook-controller kubernetes/guestbook name=guestbook 3
```

Once that's up (it may take ten to thirty seconds to create the pods) you can list the pods in the cluster, to verify that the master, slaves and guestbook frontends are running:

```shell
$ cluster/kubecfg.sh list pods
ID Image(s) Host Labels Status
---------- ---------- ---------- ---------- ----------
redis-master-pod gurpartap/redis kubernetes-minion-3.c.briandpe-api.internal name=redis,role=master Running
4d65822107fcfd52 gurpartap/redis kubernetes-minion-3.c.briandpe-api.internal name=redis,role=slave,replicationController=redis-slave-controller Running
380704bb7b4d7c03 kubernetes/guestbook kubernetes-minion-3.c.briandpe-api.internal name=guestbook,replicationController=guestbook-controller Running
55104dc76695721d kubernetes/guestbook kubernetes-minion-2.c.briandpe-api.internal name=guestbook,replicationController=guestbook-controller Running
365a858149c6e2d1 kubernetes/guestbook kubernetes-minion-1.c.briandpe-api.internal name=guestbook,replicationController=guestbook-controller Running
78629a0f5f3f164f gurpartap/redis kubernetes-minion-4.c.briandpe-api.internal name=redis,role=slave,replicationController=redis-slave-controller Running
$ cluster/kubectl.sh get pods
ID IMAGE(S) HOST LABELS STATUS
redis-master-pod gurpartap/redis kubernetes-minion-1.c.thockin-dev.internal/86.75.30.9 name=redis,role=master Running
1472fd26-54d6-11e4-90fd-42010af00690 gurpartap/redis kubernetes-minion-4.c.thockin-dev.internal/12.34.56.78 name=redis,replicationController=redis-slave-controller,role=slave Running
1473363e-54d6-11e4-90fd-42010af00690 gurpartap/redis kubernetes-minion-3.c.thockin-dev.internal/9.3.19.76 name=redis,replicationController=redis-slave-controller,role=slave Running
fc58aa01-54d6-11e4-90fd-42010af00690 kubernetes/guestbook kubernetes-minion-1.c.thockin-dev.internal/1.18.19.78 name=guestbook,replicationController=guestbook-controller Running
fc592fbb-54d6-11e4-90fd-42010af00690 kubernetes/guestbook kubernetes-minion-1.c.thockin-dev.internal/12.9.20.9 name=guestbook,replicationController=guestbook-controller Running
fc59569e-54d6-11e4-90fd-42010af00690 kubernetes/guestbook kubernetes-minion-2.c.thockin-dev.internal/1.11.20.13 name=guestbook,replicationController=guestbook-controller Running

```

You will see a single redis master pod, two redis slaves, and three guestbook pods.

To play with the service itself, find the name of a guestbook, grab the external IP of that host from the [Google Cloud Console][cloud-console] or the `gcutil` tool, and visit `http://<host-ip>:3000`.
### Step Six: Create the guestbook service.

Just like the others, you want a service to group your guestbook pods. The service specification for the guestbook is in `examples/guestbook-go/guestbook-service.json`. There's a twist this time - because we want it to be externally visible, we set the `createExternalLoadBalancer` flag on the service.

```shell
$ cluster/kubectl.sh create -f examples/guestbook-go/guestbook-service.json

$ cluster/kubectl.sh get services
ID LABELS SELECTOR IP PORT
redis-master name=redis,role=master 10.0.0.1 6379
redis-slave name=redis,role=slave name=redis,role=slave 10.0.0.2 6379
guestbook name=guestbook 10.0.0.3 3000
```

To play with the service itself, find the external IP of the load balancer from the [Google Cloud Console][cloud-console] or the `gcutil` tool, and visit `http://<ip>:3000`.

```shell
$ gcutil listinstances
$ gcutil getforwardingrule guestbook
+---------------+-----------------------------------+
| name | guestbook |
| description | |
| creation-time | 2014-10-15T19:07:24.837-07:00 |
| region | us-central1 |
| ip | 12.34.56.78 |
| protocol | TCP |
| port-range | 3000-3000 |
| target | us-central1/targetPools/guestbook |
+---------------+-----------------------------------+
```

You may need to open the firewall for port 3000 using the [console][cloud-console] or the `gcutil` tool. The following command will allow traffic from any source to instances tagged `kubernetes-minion`:
Expand All @@ -165,7 +193,7 @@ For details about limiting traffic to specific sources, see the [gcutil document
[cloud-console]: https://console.developer.google.com
[gcutil-docs]: https://developers.google.com/compute/docs/gcutil/reference/firewall#addfirewall

### Step Six: Cleanup
### Step Seven: Cleanup

To turn down a Kubernetes cluster:

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3 changes: 2 additions & 1 deletion examples/guestbook-go/guestbook-service.json
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Expand Up @@ -4,5 +4,6 @@
"id": "guestbook",
"port": 3000,
"containerPort": "http-server",
"selector": { "name": "guestbook" }
"selector": { "name": "guestbook" },
"createExternalLoadBalancer": true
}
2 changes: 1 addition & 1 deletion examples/guestbook-go/redis-slave-controller.json
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Expand Up @@ -13,7 +13,7 @@
"containers": [{
"name": "redis-slave",
"image": "gurpartap/redis",
"command": ["sh", "-c", "redis-server /etc/redis/redis.conf --slaveof $SERVICE_HOST $REDIS_MASTER_SERVICE_PORT"],
"command": ["sh", "-c", "redis-server /etc/redis/redis.conf --slaveof $REDIS_MASTER_SERVICE_HOST $REDIS_MASTER_SERVICE_PORT"],
"ports": [{ "name": "redis-server", "containerPort": 6379 }]
}]
}
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