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Reviewed-by: Eotvos, Oliver <oliver.eotvos@t-systems.com> Co-authored-by: proposalbot <proposalbot@otc-service.com> Co-committed-by: proposalbot <proposalbot@otc-service.com>
101 lines
9.7 KiB
ReStructuredText
101 lines
9.7 KiB
ReStructuredText
:original_name: cce_10_0278.html
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.. _cce_10_0278:
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Creating a Namespace
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====================
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When to Use Namespaces
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----------------------
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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.
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For example, you can deploy workloads in a development environment into one namespace, and deploy workloads in a testing environment into another namespace.
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Prerequisites
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-------------
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At least one cluster has been created.
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Notes and Constraints
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---------------------
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A maximum of 6,000 Services can be created in each namespace. The Services mentioned here indicate the Kubernetes Service resources added for workloads.
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Namespace Types
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---------------
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Namespaces can be created in either of the following ways:
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- Created automatically: When a cluster is up, the **default**, **kube-public**, **kube-system**, and **kube-node-lease** namespaces are created by default.
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- **default**: All objects for which no namespace is specified are allocated to this namespace.
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- **kube-public**: Resources in this namespace can be accessed by all users (including unauthenticated users), such as public add-ons and container charts.
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- **kube-system**: All resources created by Kubernetes are in this namespace.
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- **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.
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- 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.
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Creating a Namespace
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--------------------
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#. Log in to the CCE console and access the cluster console.
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#. Choose **Namespaces** in the navigation pane and click **Create Namespace** in the upper right corner.
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#. Set namespace parameters based on :ref:`Table 1 <cce_10_0278__table5523151617575>`.
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.. _cce_10_0278__table5523151617575:
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.. table:: **Table 1** Parameters for creating a namespace
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+-----------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
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| Parameter | Description |
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+===================================+==========================================================================================================================================================================================================================================================================================================+
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| Name | Unique name of the created namespace. |
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+-----------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
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| Description | Description about the namespace. |
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+-----------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
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| Quota Management | Resource quotas can limit the amount of resources available in namespaces, achieving resource allocation by namespace. |
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| | |
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| | .. important:: |
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| | NOTICE: |
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| | **You are advised to set resource quotas in the namespace as required to prevent cluster or node exceptions caused by resource overload.** |
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| | 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. |
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| | Enter an integer. If the quota of a resource is not specified, no limit is posed on the resource. |
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| | If you want to limit the CPU or memory quota, you must specify the CPU or memory request value when creating a workload. |
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+-----------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
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#. When the configuration is complete, click **OK**.
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Using kubectl to Create a Namespace
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-----------------------------------
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Define a namespace.
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.. code-block::
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apiVersion: v1
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kind: Namespace
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metadata:
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name: custom-namespace
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Run the **kubectl** command to create it.
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.. code-block::
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$ kubectl create -f custom-namespace.yaml
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namespace/custom-namespace created
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You can also run the **kubectl create namespace** command to create a namespace.
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.. code-block::
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$ kubectl create namespace custom-namespace
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namespace/custom-namespace created
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