# 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. For details, see Creating a CCE Cluster.

#### 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

1. Log in to the CCE console. In the navigation pane, choose Resource Management > Namespaces. Click Create Namespace.
2. Set the parameters listed in Table 1. The parameters marked with an asterisk (*) are mandatory.

   Table 1 Parameters for creating a namespace
   Parameter | Description
   --- | ---
   * Namespace | Unique name of the created namespace.
   * Cluster | Cluster to which the namespace belongs.
   Node Affinity | If this parameter is set to on, workloads in this namespace will be scheduled only to nodes with specified labels. To add labels to a node, choose Resource Management > Nodes > Manage Labels. This parameter is displayed only for clusters of v1.13.10-r0 and later.
   Description | Description about the namespace.

   Set Resource Quotas

   Resource quotas can limit the amount of resources available in namespaces, achieving resource allocation by namespace.

   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.

   Quotas can be configured for the following resources:
   - CPU (cores)
   - Memory (MiB)
   - StatefulSet
   - Deployment
   - Job
   - Cron job
   - Pod
   - Service

   Enter an integer. If the quota of a resource is set to 0, 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.

3. When the configuration is complete, click OK.

Parent topic: Namespaces