Syntactic Restrictions

Last updated: 2019-06-04 11:49:48

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Tencent Cloud TKE To ensure steady closed-loop features, some restrictions are imposed on the Kubernetes orchestration syntax in the container platform. This document describes the restrictions and reasons for them.

Restriction on Yaml Bytes Quota

The application orchestration yaml template has a 51,200 byte size limitation.

Restriction on Supported Resource Types

Kubernetes contains many different types of resources. Only the most commonly used resources Deployment and Service are available in TKE to meet user needs. (When you create Deployment, Pod and replicaset are created automatically).

Only Deployment and Service are available in all the application orchestrations in TKE.

Restriction on Resource Name

In each service of application template, Deployment and Service resource names must be consistent with the service name.

Restriction on Namespace

(1) All the resources in the application template must be in one namespace.

(2) The kube-system namespace does not support the creation of service, so the namespace kube-system is not supported in the application template.

Restrictions on Label

(1) In an application template, you can label the resources in the service with Label. In TKE, Service searches for the corresponding Pod via Select Label, thus associating it with Deployment. Deployment is associated with Pod with its own Select Label. Therefore, in order to manage Deployment and Service, the restriction that the Select Label of Deployment must be the same as that of Service is added.

(2) By default, qcloud-app is provided for each service in the application template to identify the service, and qcloud-application-label is provided to identify the application to which the service belongs. Modification to these two labels is not supported.

Restrictions on CBS Disk Usage

(1) A CBS can only be mounted to one container pod at a time, so the maximum number of pods is 1 for all the services that use CBS disk.

(2) The services that use CBS disk can be updated only through recreation. Rolling update is not supported.