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In this tutorial, I will guide you through the steps to create new custom namespaces in Kubernetes. Namespaces are one of the key features in Kubernetes frequently used to divide the physical cluster into multiple virtual clusters. Each virtual cluster acts as a namespace under which multiple resources can be created.
What is Namespace in Kubernetes
Namespaces are logical segmentation of Kubernetes Cluster resources like pods, services, replication controllers and so on. It is mostly required when you want to divide Kubernetes Cluster resources between different users via resource quotas. So one resource under a namespace cannot be shared with another namespace.
However there are some resources in Kubernetes like nodes and persistent volumes which does not lie in any namespace. You can check more about namespaces on Kubernetes Documentation.
How to Create New Custom Namespaces in Kubernetes
Also Read: Create a Service to Expose Your Apps on Kubernetes(v1.16)
Method 1: Create Namespaces Using YAML File
In this method you need to use below template to create a namespace where you need to define the apiVersion, kind, metadata and the namespace name under metadata. It is also the recommended way where you can not only create namespaces but the pods and other resources using single YAML file.
apiVersion: v1
kind: Namespace
metadata:
name: <name_of_namespace>
Here we are trying to create a new custom namespace appcom using YAML file as shown in below example.
[root@localhost ~]# vi appcom.yml apiVersion: v1 kind: Namespace metadata: name: appcom
As of now we have below namespaces currently available in Kubernetes Cluster. From the output, you can check the List of namespaces, its current status and the total time from when the namespaces were created.
[root@localhost ~]# kubectl get namespaces NAME STATUS AGE nginxnam Active 75m default Active 77m kube-node-lease Active 77m kube-public Active 77m kube-system Active 77m example Active 42m
nginxnam : This is custom created namespace for all Nginx applications.
default : It is the default namespace for all the objects which does not have any namespace.
kube-node-lease : This namespace is for leased objects which improves the node heartbeat as cluster scales.
kube-public : This namespace is used by the objects which was created by Kubernetes System.
kube-system : This namespace gets automatically created and is mostly reserved for cluster usage by all the users.
example : This is also a custom namespace created earlier for all example applications.
Now to create our new custom namespace you need to use kubectl apply -f appcom.yml command as shown below. This will create appcom namespace as evident from below output.
[root@localhost ~]# kubectl apply -f appcom.yml namespace/appcom created
Once it is created you can again run kubectl get namespaces command and check the status of our custom namespace. From below output you can notice that appcom namespace is been active from last 69 seconds.
[root@localhost ~]# kubectl get namespaces NAME STATUS AGE nginxnam Active 78m appcom Active 69s default Active 80m hello-name Active 80m kube-public Active 80m kube-system Active 80m example Active 45m
If you want to delete the namespaces then you need to use kubectl delete namespaces <name_of_namespace> command. Here we are trying to delete appcom namespace using kubectl delete namespaces appcom command as shown below.
[root@localhost ~]# kubectl delete namespaces appcom namespace "appcom" deleted
Method 2: Create Namespaces Without Using Any YAML File
Second method that you can use to create namespace would be directly through kubectl create namespace <namespace_name> command without using any YAML file as shown below. Here we are trying to create appcom namespace using kubectl create namespace appcom command.
[root@localhost ~]# kubectl create namespace appcom namespace/appcom created
Similarly like above if you want you can delete appcom namespace using kubectl delete namespaces appcom command as shown below.
[root@localhost ~]# kubectl delete namespaces appcom namespace "appcom" deleted
You can verify the successful deletion using kubectl get namespaces command as shown below. Now you don’t see that namespace in the shown output.
[root@localhost ~]# kubectl get namespaces NAME STATUS AGE nginxnam Active 83m default Active 85m kube-example Active 85m kube-public Active 85m kube-system Active 85m example Active 50m
Method 3: Create Namespaces Using JSON File
Another method that you can use to create namespaces is through JSON File. Few programmers and developers comfortable in JSON prefers to use JSON file to create namespaces. Syntax of creating Namespace is mentioned below. As you can see from below syntax it is not much different from YAML File.
{ "apiVersion": "v1", "kind": "Namespace", "metadata": { "name": "<namespace_name>", "labels": { "name": "<label_name>" } } }
Like shown in above methods, we are creating appcom namespace but this time is through JSON file instead of using YAML file as you can see below.
[root@localhost ~]# vi appcom.json { "apiVersion": "v1", "kind": "Namespace", "metadata": { "name": "appcom", "labels": { "name": "appcom" } } }
Now to create appcom namespace using JSON file you need to use kubectl create -f appcom.json command as shown below.
[root@localhost ~]# kubectl create -f appcom.json namespace/appcom created
Once it is created you can again run kubectl get namespaces command like above and check the status of our custom namespace. It shows Active from last 10 seconds which means it is created successfully and working fine.
[root@localhost ~]# kubectl get namespaces NAME STATUS AGE nginxnam Active 88m appcom Active 10s default Active 90m hello-name Active 90m kube-public Active 90m kube-system Active 90m example Active 55m
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