Procedure
Log on to the CloudOps Orchestration Service (OOS) console. In the left-side navigation pane, choose Server Management > Extensions. On the Custom Extensions tab of the Extensions page, click Create Custom Extension.
In the Basic Information step of the Create Custom Extension wizard, enter the extension name, extension description, and version description, and specify the applicable scope of the extension.
Extension Name: The name can be up to 50 characters in length and can contain only letters, digits, and hyphens (-).
Extension Description: Describe the usage scenarios of the extension as accurately as possible to facilitate maintenance.
Version Description: When you create an extension, the system automatically identifies the first version as v1. You can enter a description for the version as required. After the extension is created, you can view the version number and version details on the extension details page. You can use the extension update feature to modify the extension. When you update the extension, the system automatically generates the v2 version. Later versions are generated in the same manner.
Extension Applicable Scope: Specify the applicable conditions of the extension, including the supported instance families, image types, and operating systems and versions. You can select the extension on the Elastic Compute Service (ECS) buy page or the details page of an ECS instance only if the applicable conditions are met.
Installation Command Parameters: Specify the input parameter of the extension installation command. You can add multiple parameters. The parameter type can be String, Numeric, or Boolean. You can define the parameter name, default value, and parameter description for each parameter. You must assign values to these parameters when you install the extension on the ECS buy page or the details page of an ECS instance.
You can reference an installation command parameter in the installation script by using braces {}, as shown in the following sample script. When you install the extension later, you can pass a specific value by using the parameter. 
Sample installation script:yum install -y {{para1}}
Click Next Step to go to the Extension Configuration step.
In this step, you can add multiple extension configurations. In each configuration, you can select the operating system, architecture, Object Storage Service (OSS) bucket, and software package. You can enter the installation and uninstallation scripts for the specified software package. When you install the extension on an ECS instance, the system finds the extension configuration that is applicable to the operating system and architecture of the ECS instance, downloads the specified software package, and then runs the installation or uninstallation script. This allows you to install the extension with a few clicks.
Click Create to create the custom extension.
View the details of an extension: After the extension is created, you can click Details in the Actions column of the extension on the Custom Extensions tab of the Extensions page to go to the details page of the extension. On the details page, the global information of the extension and the information of the current version are displayed. You can select the version that you want to view from the version drop-down list. When you switch to another version, the version information and extension configurations change.
