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Rewrite guestbook example to use kube-dns instead of host:port

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This fixes #5091
This commit is contained in:
Piotr Szczesniak 2015-03-11 06:43:36 +01:00
parent 6d465c4d86
commit 4679a37b38
8 changed files with 47 additions and 65 deletions
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64
examples/guestbook/README.md
View File

@ -161,7 +161,7 @@ Use the file `examples/guestbook/redis-slave-controller.json`, which looks like
"id": "redis-slave",
"containers": [{
"name": "redis-slave",
"image": "brendanburns/redis-slave",
"image": "kubernetes/redis-slave:v2",
"cpu": 200,
"ports": [{"containerPort": 6379}]
}]
@ -187,25 +187,23 @@ redis-slave-controller
$ kubectl get rc
CONTROLLER CONTAINER(S) IMAGE(S) SELECTOR REPLICAS
redis-master-controller redis-master dockerfile/redis name=redis-master 1
redis-slave-controller redis-slave brendanburns/redis-slave name=redis-slave 2
redis-slave-controller redis-slave kubernetes/redis-slave:v2 name=redis-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:
The redis slave is started with the following command:
```shell
redis-server --slaveof ${REDIS_MASTER_SERVICE_HOST:-$SERVICE_HOST} $REDIS_MASTER_SERVICE_PORT
redis-server --slaveof redis-master 6379
```
You might be curious about where the *REDIS_MASTER_SERVICE_HOST* is coming from. It is provided to this container when it is launched via the kubernetes services, which create environment variables (there is a well defined syntax for how service names get transformed to environment variable names in the documentation linked above).
Once that's up you can list the pods in the cluster, to verify that the master and slaves are running:
```shell
$ kubectl get pods
POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS
redis-master-controller-gb50a 10.244.3.7 redis-master dockerfile/redis kubernetes-minion-7agi.c.hazel-mote-834.internal/104.154.54.203 app=redis,name=redis-master Running
redis-slave-controller-182tv 10.244.3.6 redis-slave brendanburns/redis-slave kubernetes-minion-7agi.c.hazel-mote-834.internal/104.154.54.203 app=redis,name=redis-slave,uses=redis-master Running
redis-slave-controller-zwk1b 10.244.2.8 redis-slave brendanburns/redis-slave kubernetes-minion-3vxa.c.hazel-mote-834.internal/104.154.54.6 app=redis,name=redis-slave,uses=redis-master Running
redis-slave-controller-182tv 10.244.3.6 redis-slave kubernetes/redis-slave:v2 kubernetes-minion-7agi.c.hazel-mote-834.internal/104.154.54.203 app=redis,name=redis-slave,uses=redis-master Running
redis-slave-controller-zwk1b 10.244.2.8 redis-slave kubernetes/redis-slave:v2 kubernetes-minion-3vxa.c.hazel-mote-834.internal/104.154.54.6 app=redis,name=redis-slave,uses=redis-master Running
```
You will see a single redis master pod and two redis slave pods.
@ -218,7 +216,7 @@ The service specification for the slaves is in `examples/guestbook/redis-slave-s
```js
{
"id": "redisslave",
"id": "redis-slave",
"kind": "Service",
"apiVersion": "v1beta1",
"port": 6379,
@ -238,12 +236,12 @@ Now that you have created the service specification, create it in your cluster b
```shell
$ kubectl create -f examples/guestbook/redis-slave-service.json
redisslave
redis-slave
$ kubectl get services
NAME LABELS SELECTOR IP PORT
redis-master name=redis-master name=redis-master 10.0.246.242 6379
redisslave name=redis-slave name=redis-slave 10.0.72.62 6379
redis-slave name=redis-slave name=redis-slave 10.0.72.62 6379
```
### Step Five: Create the frontend pod
@ -269,7 +267,7 @@ The pod is described in the file `examples/guestbook/frontend-controller.json`:
"id": "frontend",
"containers": [{
"name": "php-redis",
"image": "kubernetes/example-guestbook-php-redis",
"image": "kubernetes/example-guestbook-php-redis:v2",
"cpu": 100,
"memory": 50000000,
"ports": [{"name": "http-server", "containerPort": 80}]
@ -294,9 +292,9 @@ frontend-controller
$ kubectl get rc
CONTROLLER CONTAINER(S) IMAGE(S) SELECTOR REPLICAS
frontend-controller php-redis kubernetes/example-guestbook-php-redis name=frontend 3
frontend-controller php-redis kubernetes/example-guestbook-php-redis:v2 name=frontend 3
redis-master-controller redis-master dockerfile/redis name=redis-master 1
redis-slave-controller redis-slave brendanburns/redis-slave name=redis-slave 2
redis-slave-controller redis-slave kubernetes/redis-slave:v2 name=redis-slave 2
```
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 frontends are running:
@ -304,12 +302,12 @@ Once that's up (it may take ten to thirty seconds to create the pods) you can li
```shell
$ kubectl get pods
POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS
frontend-controller-5m1zc 10.244.1.131 php-redis kubernetes/example-guestbook-php-redis kubernetes-minion-3vxa.c.hazel-mote-834.internal/146.148.71.71 app=frontend,name=frontend,uses=redis-slave,redis-master Running
frontend-controller-ckn42 10.244.2.134 php-redis kubernetes/example-guestbook-php-redis kubernetes-minion-by92.c.hazel-mote-834.internal/104.154.54.6 app=frontend,name=frontend,uses=redis-slave,redis-master Running
frontend-controller-v5drx 10.244.0.128 php-redis kubernetes/example-guestbook-php-redis kubernetes-minion-wilb.c.hazel-mote-834.internal/23.236.61.63 app=frontend,name=frontend,uses=redis-slave,redis-master Running
frontend-controller-5m1zc 10.244.1.131 php-redis kubernetes/example-guestbook-php-redis:v2 kubernetes-minion-3vxa.c.hazel-mote-834.internal/146.148.71.71 app=frontend,name=frontend,uses=redis-slave,redis-master Running
frontend-controller-ckn42 10.244.2.134 php-redis kubernetes/example-guestbook-php-redis:v2 kubernetes-minion-by92.c.hazel-mote-834.internal/104.154.54.6 app=frontend,name=frontend,uses=redis-slave,redis-master Running
frontend-controller-v5drx 10.244.0.128 php-redis kubernetes/example-guestbook-php-redis:v2 kubernetes-minion-wilb.c.hazel-mote-834.internal/23.236.61.63 app=frontend,name=frontend,uses=redis-slave,redis-master Running
redis-master-controller-gb50a 10.244.3.7 redis-master dockerfile/redis kubernetes-minion-7agi.c.hazel-mote-834.internal/104.154.54.203 app=redis,name=redis-master Running
redis-slave-controller-182tv 10.244.3.6 redis-slave brendanburns/redis-slave kubernetes-minion-7agi.c.hazel-mote-834.internal/104.154.54.203 app=redis,name=redis-slave,uses=redis-master Running
redis-slave-controller-zwk1b 10.244.2.8 redis-slave brendanburns/redis-slave kubernetes-minion-3vxa.c.hazel-mote-834.internal/104.154.54.6 app=redis,name=redis-slave,uses=redis-master Running
redis-slave-controller-182tv 10.244.3.6 redis-slave kubernetes/redis-slave:v2 kubernetes-minion-7agi.c.hazel-mote-834.internal/104.154.54.203 app=redis,name=redis-slave,uses=redis-master Running
redis-slave-controller-zwk1b 10.244.2.8 redis-slave kubernetes/redis-slave:v2 kubernetes-minion-3vxa.c.hazel-mote-834.internal/104.154.54.6 app=redis,name=redis-slave,uses=redis-master Running
```
You will see a single redis master pod, two redis slaves, and three frontend pods.
@ -331,21 +329,17 @@ if (isset($_GET['cmd']) === true) {
if ($_GET['cmd'] == 'set') {
$client = new Predis\Client([
'scheme' => 'tcp',
'host' => getenv('REDIS_MASTER_SERVICE_HOST') ?: getenv('SERVICE_HOST'),
'port' => getenv('REDIS_MASTER_SERVICE_PORT'),
'host' => 'redis-master',
'port' => 6379,
]);
$client->set($_GET['key'], $_GET['value']);
print('{"message": "Updated"}');
} else {
$read_port = getenv('REDIS_MASTER_SERVICE_PORT');
if (isset($_ENV['REDISSLAVE_SERVICE_PORT'])) {
$read_port = getenv('REDISSLAVE_SERVICE_PORT');
}
$client = new Predis\Client([
'scheme' => 'tcp',
'host' => getenv('REDIS_MASTER_SERVICE_HOST') ?: getenv('SERVICE_HOST'),
'port' => $read_port,
'host' => 'redis-slave',
'port' => 6379,
]);
$value = $client->get($_GET['key']);
@ -393,7 +387,7 @@ $ kubectl get services
NAME LABELS SELECTOR IP PORT
frontend name=frontend name=frontend 10.0.93.211 8000
redis-master name=redis-master name=redis-master 10.0.246.242 6379
redisslave name=redis-slave name=redis-slave 10.0.72.62 6379
redis-slave name=redis-slave name=redis-slave 10.0.72.62 6379
```
### A few Google Container Engine specifics for playing around with the services.
@ -487,15 +481,7 @@ $> watch -n 1 docker ps
If you run this on a node to which the frontend is assigned, you will eventually see the frontend container turns on. At that point, this basic error will likely go away.
2) *When Redis can't connect to master*:
```shell
<b>Fatal error</b>: Uncaught exception 'Predis\Connection\ConnectionException' with message 'php_network_getaddresses: getaddrinfo failed: Name or service not known [tcp://:0]' in /vendor/predis/predis/lib/Predis/Connection/AbstractConnection.php:141
```
The fix: Make sure that environmental variables are being set correctly. In particular, the PHP containers need to be started with the environment variables for the redis master (i.e. REDIS_MASTER_SERVICE_HOST and REDIS_MASTER_PORT).
3) *Temporarily, while waiting for the app to come up* , you might see a few of these:
2) *Temporarily, while waiting for the app to come up* , you might see a few of these:
```shell
==> default: <br />
@ -513,7 +499,7 @@ $> docker logs 26af6bd5ac12
[9] 20 Feb 23:47:52.005 * MASTER <-> SLAVE sync started
```
4) *When security issues cause redis writes to fail* you may have to run *docker logs* on the redis containers:
3) *When security issues cause redis writes to fail* you may have to run *docker logs* on the redis containers:
```shell
==> default: <b>Fatal error</b>: Uncaught exception 'Predis\ServerException' with message 'MISCONF Redis is configured to save RDB snapshots, but is currently not able to persist on disk. Commands that may modify the data set are disabled. Please check Redis logs for details about the error.' in /vendor/predis/predis/lib/Predis/Client.php:282"

2
examples/guestbook/frontend-controller.json
View File

@ -12,7 +12,7 @@
"id": "frontend",
"containers": [{
"name": "php-redis",
"image": "kubernetes/example-guestbook-php-redis",
"image": "kubernetes/example-guestbook-php-redis:v2",
"cpu": 100,
"memory": 50000000,
"ports": [{"name": "http-server", "containerPort": 80}]

14
examples/guestbook/php-redis/index.php
View File

@ -12,21 +12,17 @@ if (isset($_GET['cmd']) === true) {
if ($_GET['cmd'] == 'set') {
$client = new Predis\Client([
'scheme' => 'tcp',
'host' => getenv('REDIS_MASTER_SERVICE_HOST') ?: getenv('SERVICE_HOST'),
'port' => getenv('REDIS_MASTER_SERVICE_PORT'),
'host' => 'redis-master',
'port' => 6379,
]);
$client->set($_GET['key'], $_GET['value']);
print('{"message": "Updated"}');
} else {
$read_port = getenv('REDIS_MASTER_SERVICE_PORT');
if (isset($_ENV['REDISSLAVE_SERVICE_PORT'])) {
$read_port = getenv('REDISSLAVE_SERVICE_PORT');
}
$client = new Predis\Client([
'scheme' => 'tcp',
'host' => getenv('REDIS_MASTER_SERVICE_HOST') ?: getenv('SERVICE_HOST'),
'port' => $read_port,
'host' => 'redis-slave',
'port' => 6379,
]);
$value = $client->get($_GET['key']);

2
examples/guestbook/redis-slave-controller.json
View File

@ -12,7 +12,7 @@
"id": "redis-slave",
"containers": [{
"name": "redis-slave",
"image": "brendanburns/redis-slave",
"image": "kubernetes/redis-slave:v2",
"cpu": 200,
"ports": [{"containerPort": 6379}]
}]

2
examples/guestbook/redis-slave-service.json
View File

@ -1,5 +1,5 @@
{
"id": "redisslave",
"id": "redis-slave",
"kind": "Service",
"apiVersion": "v1beta1",
"port": 6379,

2
examples/guestbook/redis-slave/run.sh
View File

@ -14,4 +14,4 @@
# See the License for the specific language governing permissions and
# limitations under the License.
redis-server --slaveof ${REDIS_MASTER_SERVICE_HOST:-$SERVICE_HOST} $REDIS_MASTER_SERVICE_PORT
redis-server --slaveof redis-master 6379

6
hack/test-cmd.sh
View File

@ -419,13 +419,13 @@ __EOF__
kubectl create -f examples/guestbook/redis-master-service.json "${kube_flags[@]}"
kubectl create -f examples/guestbook/redis-slave-service.json "${kube_flags[@]}"
# Post-condition: redis-master and redis-slave services are running
kube::test::get_object_assert services "{{range.items}}{{.$id_field}}:{{end}}" 'kubernetes:kubernetes-ro:redis-master:redisslave:'
kube::test::get_object_assert services "{{range.items}}{{.$id_field}}:{{end}}" 'kubernetes:kubernetes-ro:redis-master:redis-slave:'
### Delete multiple services at once
# Pre-condition: redis-master and redis-slave services are running
kube::test::get_object_assert services "{{range.items}}{{.$id_field}}:{{end}}" 'kubernetes:kubernetes-ro:redis-master:redisslave:'
kube::test::get_object_assert services "{{range.items}}{{.$id_field}}:{{end}}" 'kubernetes:kubernetes-ro:redis-master:redis-slave:'
# Command
kubectl delete services redis-master redisslave "${kube_flags[@]}" # delete multiple services at once
kubectl delete services redis-master redis-slave "${kube_flags[@]}" # delete multiple services at once
# Post-condition: Only the default kubernetes services are running
kube::test::get_object_assert services "{{range.items}}{{.$id_field}}:{{end}}" 'kubernetes:kubernetes-ro:'

2
pkg/kubectl/cmd/delete_test.go
View File

@ -172,7 +172,7 @@ func TestDeleteDirectory(t *testing.T) {
cmd.Flags().Set("filename", "../../../examples/guestbook")
cmd.Run(cmd, []string{})
if buf.String() != "frontend-controller\nfrontend\nredis-master-controller\nredis-master\nredis-slave-controller\nredisslave\n" {
if buf.String() != "frontend-controller\nfrontend\nredis-master-controller\nredis-master\nredis-slave-controller\nredis-slave\n" {
t.Errorf("unexpected output: %s", buf.String())
}
}