:original_name: cce_10_0278.html
.. _cce_10_0278:
Creating a Namespace
====================
When to Use Namespaces
----------------------
A namespace is a collection of resources and objects. Multiple namespaces can be created inside a cluster and isolated from each other. This enables namespaces to share the same cluster Services without affecting each other.
For example, you can deploy workloads in a development environment into one namespace, and deploy workloads in a testing environment into another namespace.
Prerequisites
-------------
At least one cluster has been created.
Notes and Constraints
---------------------
A maximum of 6,000 Services can be created in each namespace. The Services mentioned here indicate the Kubernetes Service resources added for workloads.
Namespace Types
---------------
Namespaces can be created in either of the following ways:
- Created automatically: When a cluster is up, the **default**, **kube-public**, **kube-system**, and **kube-node-lease** namespaces are created by default.
- **default**: All objects for which no namespace is specified are allocated to this namespace.
- **kube-public**: Resources in this namespace can be accessed by all users (including unauthenticated users), such as public add-ons and container charts.
- **kube-system**: All resources created by Kubernetes are in this namespace.
- **kube-node-lease**: Each node has an associated Lease object in this namespace. The object is periodically updated by the node. Both NodeStatus and NodeLease are considered as heartbeats from a node. In versions earlier than v1.13, only NodeStatus is available. The NodeLease feature is introduced in v1.13. NodeLease is more lightweight than NodeStatus. This feature significantly improves the cluster scalability and performance.
- Created manually: You can create namespaces to serve separate purposes. For example, you can create three namespaces, one for a development environment, one for joint debugging environment, and one for test environment. You can also create one namespace for login services and one for game services.
Creating a Namespace
--------------------
#. Log in to the CCE console and access the cluster console.
#. Choose **Namespaces** in the navigation pane and click **Create Namespace** in the upper right corner.
#. Set namespace parameters based on :ref:`Table 1 `.
.. _cce_10_0278__table5523151617575:
.. table:: **Table 1** Parameters for creating a namespace
+-----------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Parameter | Description |
+===================================+==========================================================================================================================================================================================================================================================================================================+
| Name | Unique name of the created namespace. |
+-----------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Description | Description about the namespace. |
+-----------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Quota Management | Resource quotas can limit the amount of resources available in namespaces, achieving resource allocation by namespace. |
| | |
| | .. important:: |
| | |
| | NOTICE: |
| | **You are advised to set resource quotas in the namespace as required to prevent cluster or node exceptions caused by resource overload.** |
| | |
| | For example, the default number of pods that can be created on each node in a cluster is 110. If you create a cluster with 50 nodes, you can create a maximum of 5,500 pods. Therefore, you can set a resource quota to ensure that the total number of pods in all namespaces does not exceed 5,500. |
| | |
| | Enter an integer. If the quota of a resource is not specified, no limit is posed on the resource. |
| | |
| | If you want to limit the CPU or memory quota, you must specify the CPU or memory request value when creating a workload. |
+-----------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
#. When the configuration is complete, click **OK**.
Using kubectl to Create a Namespace
-----------------------------------
Define a namespace.
.. code-block::
apiVersion: v1
kind: Namespace
metadata:
name: custom-namespace
Run the **kubectl** command to create it.
.. code-block::
$ kubectl create -f custom-namespace.yaml
namespace/custom-namespace created
You can also run the **kubectl create namespace** command to create a namespace.
.. code-block::
$ kubectl create namespace custom-namespace
namespace/custom-namespace created