--- reviewers: - derekwaynecarr - janetkuo title: Namespaces Walkthrough content_type: task weight: 260 --- Kubernetes {{< glossary_tooltip text="namespaces" term_id="namespace" >}} help different projects, teams, or customers to share a Kubernetes cluster. It does this by providing the following: 1. A scope for [Names](/docs/concepts/overview/working-with-objects/names/). 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. ## {{% heading "prerequisites" %}} {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}} ## Prerequisites This example assumes the following: 1. You have an [existing Kubernetes cluster](/docs/setup/). 2. You have a basic understanding of Kubernetes {{< glossary_tooltip text="Pods" term_id="pod" >}}, {{< glossary_tooltip term_id="service" text="Services" >}}, and {{< glossary_tooltip text="Deployments" term_id="deployment" >}}. ## 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 Deployments used by the cluster. Assuming you have a fresh cluster, you can inspect the available namespaces by doing the following: ```shell kubectl get namespaces ``` ``` NAME STATUS AGE default Active 13m ``` ## 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 Deployments 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 Deployments 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 [`namespace-dev.yaml`](/examples/admin/namespace-dev.yaml) which describes a `development` namespace: {{% code_sample language="yaml" file="admin/namespace-dev.yaml" %}} Create the `development` namespace using kubectl. ```shell kubectl create -f https://k8s.io/examples/admin/namespace-dev.yaml ``` Save the following contents into file [`namespace-prod.yaml`](/examples/admin/namespace-prod.yaml) which describes a `production` namespace: {{% code_sample language="yaml" file="admin/namespace-prod.yaml" %}} And then let's create the `production` namespace using kubectl. ```shell kubectl create -f https://k8s.io/examples/admin/namespace-prod.yaml ``` To be sure things are right, let's list all of the namespaces in our cluster. ```shell kubectl get namespaces --show-labels ``` ``` NAME STATUS AGE LABELS default Active 32m development Active 29s name=development production Active 23s name=production ``` ## Create pods in each namespace A Kubernetes namespace provides the scope for Pods, Services, and Deployments 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 Deployment and Pods in the `development` namespace. We first check what is the current context: ```shell kubectl config view ``` ```yaml apiVersion: v1 clusters: - cluster: certificate-authority-data: REDACTED server: https://130.211.122.180 name: lithe-cocoa-92103_kubernetes contexts: - context: cluster: lithe-cocoa-92103_kubernetes user: lithe-cocoa-92103_kubernetes name: lithe-cocoa-92103_kubernetes current-context: lithe-cocoa-92103_kubernetes kind: Config preferences: {} users: - name: lithe-cocoa-92103_kubernetes user: client-certificate-data: REDACTED client-key-data: REDACTED token: 65rZW78y8HbwXXtSXuUw9DbP4FLjHi4b - name: lithe-cocoa-92103_kubernetes-basic-auth user: password: h5M0FtUUIflBSdI7 username: admin ``` ```shell kubectl config current-context ``` ``` lithe-cocoa-92103_kubernetes ``` The next step is to define a context for the kubectl client to work in each namespace. The value of "cluster" and "user" fields are copied from the current context. ```shell kubectl config set-context dev --namespace=development \ --cluster=lithe-cocoa-92103_kubernetes \ --user=lithe-cocoa-92103_kubernetes kubectl config set-context prod --namespace=production \ --cluster=lithe-cocoa-92103_kubernetes \ --user=lithe-cocoa-92103_kubernetes ``` By default, the above commands add two contexts that are saved into file `.kube/config`. You can now view the contexts and alternate against the two new request contexts depending on which namespace you wish to work against. To view the new contexts: ```shell kubectl config view ``` ```yaml apiVersion: v1 clusters: - cluster: certificate-authority-data: REDACTED server: https://130.211.122.180 name: lithe-cocoa-92103_kubernetes contexts: - context: cluster: lithe-cocoa-92103_kubernetes user: lithe-cocoa-92103_kubernetes name: lithe-cocoa-92103_kubernetes - context: cluster: lithe-cocoa-92103_kubernetes namespace: development user: lithe-cocoa-92103_kubernetes name: dev - context: cluster: lithe-cocoa-92103_kubernetes namespace: production user: lithe-cocoa-92103_kubernetes name: prod current-context: lithe-cocoa-92103_kubernetes kind: Config preferences: {} users: - name: lithe-cocoa-92103_kubernetes user: client-certificate-data: REDACTED client-key-data: REDACTED token: 65rZW78y8HbwXXtSXuUw9DbP4FLjHi4b - name: lithe-cocoa-92103_kubernetes-basic-auth user: password: h5M0FtUUIflBSdI7 username: admin ``` Let's switch to operate in the `development` namespace. ```shell kubectl config use-context dev ``` You can verify your current context by doing the following: ```shell kubectl config current-context ``` ``` dev ``` 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 contents. {{% code_sample file="admin/snowflake-deployment.yaml" %}} Apply the manifest to create a Deployment ```shell kubectl apply -f https://k8s.io/examples/admin/snowflake-deployment.yaml ``` We have created a deployment whose replica size is 2 that is running the pod called `snowflake` with a basic container that serves the hostname. ```shell kubectl get deployment ``` ``` NAME READY UP-TO-DATE AVAILABLE AGE snowflake 2/2 2 2 2m ``` ```shell kubectl get pods -l app=snowflake ``` ``` NAME READY STATUS RESTARTS AGE snowflake-3968820950-9dgr8 1/1 Running 0 2m snowflake-3968820950-vgc4n 1/1 Running 0 2m ``` 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 kubectl config use-context prod ``` The `production` namespace should be empty, and the following commands should return nothing. ```shell kubectl get deployment kubectl get pods ``` Production likes to run cattle, so let's create some cattle pods. ```shell kubectl create deployment cattle --image=registry.k8s.io/serve_hostname --replicas=5 kubectl get deployment ``` ``` NAME READY UP-TO-DATE AVAILABLE AGE cattle 5/5 5 5 10s ``` ```shell kubectl get pods -l app=cattle ``` ``` NAME READY STATUS RESTARTS AGE cattle-2263376956-41xy6 1/1 Running 0 34s cattle-2263376956-kw466 1/1 Running 0 34s cattle-2263376956-n4v97 1/1 Running 0 34s cattle-2263376956-p5p3i 1/1 Running 0 34s cattle-2263376956-sxpth 1/1 Running 0 34s ``` 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.