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Merge pull request #5050 from dchen1107/cleanup

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Convert both namespace and limitrange examples to v1beta3
This commit is contained in:
Derek Carr
2015-03-06 13:26:23 -05:00
parent 0d6b57ccdb a934efe3e5
commit d99e9f728c
6 changed files with 283 additions and 0 deletions
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examples/kubernetes-namespaces/v1beta3/README.md Normal file
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## Kubernetes Namespaces
Kubernetes Namespaces help different projects, teams, or customers to share a Kubernetes cluster.
It does this by providing the following:
1. A scope for [Names](../../../docs/identifiers.md).
2. A mechanism to attach authorization and policy to a subsection of the cluster.
Use of multiple namespaces is optional.
This example demonstrates how to use Kubernetes namespaces to subdivide your cluster.
### Step Zero: Prerequisites
This example assumes the following:
1. You have an existing Kubernetes cluster.
2. You have a basic understanding of Kubernetes pods, services, and replication controllers.
### Step One: Understand the default namespace
By default, a Kubernetes cluster will instantiate a default namespace when provisioning the cluster to hold the default set of pods,
services, and replication controllers used by the cluster.
Assuming you have a fresh cluster, you can introspect the available namespace's by doing the following:
```shell
$ cluster/kubectl.sh get namespaces
NAME LABELS
default <none>
```
### Step Two: Create new namespaces
For this exercise, we will create two additional Kubernetes namespaces to hold our content.
Let's imagine a scenario where an organization is using a shared Kubernetes cluster for development and production use cases.
The development team would like to maintain a space in the cluster where they can get a view on the list of pods, services, and replication-controllers
they use to build and run their application. In this space, Kubernetes resources come and go, and the restrictions on who can or cannot modify resources
are relaxed to enable agile development.
The operations team would like to maintain a space in the cluster where they can enforce strict procedures on who can or cannot manipulate the set of
pods, services, and replication controllers that run the production site.
One pattern this organization could follow is to partition the Kubernetes cluster into two namespaces: development and production.
Let's create two new namespaces to hold our work.
Use the file `examples/kubernetes-namespaces/v1beta3/namespace-dev.json` which describes a development namespace:
```js
{
"kind": "Namespace",
"apiVersion":"v1beta3",
"name": "development",
"spec": {},
"labels": {
"name": "development"
},
}
```
Create the development namespace using kubectl.
```shell
$ cluster/kubectl.sh create -f examples/kubernetes-namespaces/v1beta3/namespace-dev.json
```
And then lets create the production namespace using kubectl.
```shell
$ cluster/kubectl.sh create -f examples/kubernetes-namespaces/v1beta3/namespace-prod.json
```
To be sure things are right, let's list all of the namespaces in our cluster.
```shell
$ cluster/kubectl.sh get namespaces
NAME LABELS
default <none>
development name=development
production name=production
```
### Step Three: Create pods in each namespace
A Kubernetes namespace provides the scope for pods, services, and replication controllers in the cluster.
Users interacting with one namespace do not see the content in another namespace.
To demonstrate this, let's spin up a simple replication controller and pod in the development namespace.
The first step is to define a context for the kubectl client to work in each namespace.
```shell
$ cluster/kubectl.sh config set-context dev --namespace=development
$ cluster/kubectl.sh config set-context prod --namespace=production
```
The above commands provided two request contexts you can alternate against depending on what namespace you
wish to work against.
Let's switch to operate in the development namespace.
```shell
$ cluster/kubectl.sh config use-context dev
```
You can verify your current context by doing the following:
```shell
$ cluster/kubectl.sh config view
clusters: {}
contexts:
dev:
cluster: ""
namespace: development
user: ""
prod:
cluster: ""
namespace: production
user: ""
current-context: dev
preferences: {}
users: {}
```
At this point, all requests we make to the Kubernetes cluster from the command line are scoped to the development namespace.
Let's create some content.
```shell
$ cluster/kubectl.sh run-container snowflake --image=kubernetes/serve_hostname --replicas=2
```
We have just created a replication controller whose replica size is 2 that is running the pod called snowflake with a basic container that just serves the hostname.
```shell
cluster/kubectl.sh get rc
CONTROLLER CONTAINER(S) IMAGE(S) SELECTOR REPLICAS
snowflake snowflake kubernetes/serve_hostname run-container=snowflake 2
$ cluster/kubectl.sh get pods
POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS
snowflake-fplln 10.246.0.5 snowflake kubernetes/serve_hostname 10.245.1.3/10.245.1.3 run-container=snowflake Running
snowflake-gziey 10.246.0.4 snowflake kubernetes/serve_hostname 10.245.1.3/10.245.1.3 run-container=snowflake Running
```
And this is great, developers are able to do what they want, and they do not have to worry about affecting content in the production namespace.
Let's switch to the production namespace and show how resources in one namespace are hidden from the other.
```shell
$ cluster/kubectl.sh config use-context prod
```
The production namespace should be empty.
```shell
$ cluster/kubectl.sh get rc
CONTROLLER CONTAINER(S) IMAGE(S) SELECTOR REPLICAS
$ cluster/kubectl.sh get pods
POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS
```
Production likes to run cattle, so let's create some cattle pods.
```shell
$ cluster/kubectl.sh run-container cattle --image=kubernetes/serve_hostname --replicas=5
$ cluster/kubectl.sh get rc
CONTROLLER CONTAINER(S) IMAGE(S) SELECTOR REPLICAS
cattle cattle kubernetes/serve_hostname run-container=cattle 5
$ cluster/kubectl.sh get pods
POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS
cattle-0133o 10.246.0.7 cattle kubernetes/serve_hostname 10.245.1.3/10.245.1.3 run-container=cattle Running
cattle-hh2gd 10.246.0.10 cattle kubernetes/serve_hostname 10.245.1.3/10.245.1.3 run-container=cattle Running
cattle-ls6k1 10.246.0.9 cattle kubernetes/serve_hostname 10.245.1.3/10.245.1.3 run-container=cattle Running
cattle-nyxxv 10.246.0.8 cattle kubernetes/serve_hostname 10.245.1.3/10.245.1.3 run-container=cattle Running
cattle-oh43e 10.246.0.6 cattle kubernetes/serve_hostname 10.245.1.3/10.245.1.3 run-container=cattle Running
```
At this point, it should be clear that the resources users create in one namespace are hidden from the other namespace.
As the policy support in Kubernetes evolves, we will extend this scenario to show how you can provide different
authorization rules for each namespace.

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examples/kubernetes-namespaces/v1beta3/namespace-dev.json Normal file
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{
"apiVersion":"v1beta3",
"kind": "Namespace",
"metadata": {
"name": "development",
},
"spec": {},
"labels": {
"name": "development"
},
}

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examples/kubernetes-namespaces/v1beta3/namespace-prod.json Normal file
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{
"apiVersion":"v1beta3",
"kind": "Namespace",
"metadata": {
"name": "production",
},
"spec": {},
"labels": {
"name": "production"
},
}

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examples/limitrange/v1beta3/invalid-pod.json Normal file
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{
"apiVersion":"v1beta3",
"kind": "Pod",
"metadata": {
"name": "invalid-pod",
},
"labels": {
"name": "invalid-pod"
},
"spec": {
"containers": [{
"name": "kubernetes-serve-hostname",
"image": "kubernetes/serve_hostname",
}]
}
}

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examples/limitrange/v1beta3/limit-range.json Normal file
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{
"apiVersion": "v1beta3",
"kind": "LimitRange",
"metadata": {
"name": "limits",
},
"spec": {
"limits": [
{
"type": "Pod",
"max": {
"memory": "1Gi",
"cpu": "2",
},
"min": {
"memory": "1Mi",
"cpu": "250m"
}
},
{
"type": "Container",
"max": {
"memory": "1Gi",
"cpu": "2",
},
"min": {
"memory": "1Mi",
"cpu": "250m"
}
},
],
}
}

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examples/limitrange/v1beta3/valid-pod.json Normal file
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{
"apiVersion":"v1beta3",
"kind": "Pod",
"metadata": {
"name": "valid-pod",
},
"labels": {
"name": "valid-pod"
},
"spec": {
"containers": [{
"name": "kubernetes-serve-hostname",
"image": "kubernetes/serve_hostname",
"resources": {
"limits": {
"cpu": "1",
"memory": "1Mi",
},
},
}]
},
}