Appendix: Custom Templates

Custom Templates Configuration

Objective

Custom templates are user-defined templates that allow for the customization and automation of network services not supported by the function pack. They define specific configurations and settings that can be applied to network devices and services, making deploying and managing network resources more efficient and consistent.

To use custom templates in Crosswork Network Controller, you must pre-configure them in Crosswork Network Services Orchestration (NSO). Once configured in NSO, the Crosswork Network Controller will display your custom template for selection when you provision a device or a service. NSO uses XML-based configuration (config) templates, which you can invoke from provisioning code or link directly to devices or services. XML templates are snippets of configuration, similar to the CDB init files, but more powerful.

Workflow

To illustrate the capabilities of custom templates, we have provided an example that uses variable substitution to create an XML template. We then walk you through importing the template in NSO and referencing it in the L2VPN service in the Crosswork Network Controller.

To use custom templates:

1. Create a sample instance with the desired device configuration on the router as follows:

   policy-map TEST-POLICY
    class class-default
     police rate 200 mbps
   !
   !
   end-policy-map
   

2. Log in to NSO CLI and sync from that device.

   admin@ncs# devices device PE99-55A1 sync-from
   

3. In NSO CLI, get the running config for the policy map. Display the configuration in an XML format.

   admin@ncs# show running-config devices device PE99-55A1 config policy-map | display xml
   <config xmlns="http://tail-f.com/ns/config/1.0">
   <devices xmlns="http://tail-f.com/ns/ncs">
   <device>
   <name>PE99-55A1</name>
   <config>
   <policy-map xmlns="http://tail-f.com/ned/cisco-ios-xr">
   <name>POLICYMAP NAME</name>
   <class>
   <class-default>
   <map>class-default</map>
   <police-rate-unit>
   <police>
   <rate>
   <cir>250</cir>
   <cir-unit>mbps</cir-unit>
   </rate>
   </police>
   </police-rate-unit>
   </class-default>
   </class>
   </policy-map>
   </config>
   </device>
   </devices>
   </config>
   

4. Copy the file output to a text or code editor. Specify the variables that can be substituted or parameterized according to your needs using curly braces and a dollar sign, {$VARIABLE}. You can prefer to keep the variable name uppercased to make it stand out more from the other XML elements in the file. Here, we created two variables, $POLICY_VAR and $RATE_MBS, for our template.

   <config xmlns="http://tail-f.com/ns/config/1.0">
   <devices xmlns="http://tail-f.com/ns/ncs">
   <template>
   <name>CT-TEMPLATE-INPUT</name>
   <ned-id>
   <id xmlns:cisco-iosxr-cli-7.52="http://tail-f.com/ns/ned-id/cisco-iosxr-cli-7.52">cisco-iosxr-cli-7.52:cisco-iosxr-cli-7.52</id>
   <config>
   <policy-map xmlns="http://tail-f.com/ned/cisco-ios-xr">
   <name>{$POLICY VAR}</name>
   <class>
   <class-default>
   <map>class-default</map>
   <police-rate-unit>
   <police>
   <rate>
   <cir>{$RATE MBS}</cir>
   <cir-unit>mbps</cir-unit>
   </rate>
   </police>
   </police-rate-unit>
   </class-default>
   </class>
   </policy-map>
   </config>
   </ned-id>
   </template>
   </devices>
   </config>
   

Creating a Skeleton Template

1. Create a skeleton template package in NSO. This will help you generate the XML structure with the correct headers. Copy the <devices> code in the below example to your skeleton template. The hostname configuration is optional and not required as a part of XML.

   Note: The custom-templates name must start with either ct- or CT- and should not include an underscore character.

   admin@ncs(config)# devices template CT-SKELETON-POLICY
   admin@ncs(config-template-CT-SKELETON-POLICY) # ned-id cisco-iosxr-cli-7.52
   admin@ncs(config-ned-id-cisco-iosxr-cli-7.52)%
   admin@ncs(config-config)# hostname TEST
   admin@ncs(config-config)# top
   config
   admin@ncs(config)# show configuration | display xml
   <devices xmlns="http://tail-f.com/ns/ncs">
   <template>
   <name>CT-SKELETON-POLICY</name>
   <ned-id>
   <id xmlns:cisco-iosxr-cli-7.52="http://tail-f.com/ns/ned-id/cisco-iosxr-cli-7.52">cisco-iosxr-cli-7.52:cisco-iosxr-cli-7.52</id>
   <config>
   <hostname xmlns="http://tail-f.com/ned/cisco-ios-xr">TEST</hostname>
   </config>
   </ned-id>
   </template>
   </devices>
   admin@ncs (config)#
   

2. Copy the policy-map <config> code you created in step 4 from your text editor.

   <policy-map xmlns="http://tail-f.com/ned/cisco-ios-xr">
   <name>{$POLICY_VAR}</name>
   <class>
   <class-default>
   <map>class-default</map>
   <police-rate-unit>
   <police>
   <rate>
   <cir>{$RATE_MBS}</cir>
   <cir-unit>mbps</cir-unit>
   </rate>
   </police>
   </police-rate-unit>
   </class-default>
   </class>
   </policy-map>
   

3. Paste it in your skeleton template.

   <devices xmlns="http://tail-f.com/ns/ncs">
   <template>
   <name>CT-SKELETON-POLICY</name>
   <ned-id>
   <id xmlns:cisco-iosxr-cli-7.52="http://tail-f.com/ns/ned-id/cisco-iosxr-cli-7.52">cisco-iosxr-cli-7.52:cisco-iosxr-cli-7.52</id>
   <config>
   <policy-map xmlns="http://tail-f.com/ned/cisco-ios-xr">
   <name>{$POLICY_VAR}</name>
   <class>
   <class-default>
   <map>class-default</map>
   <police-rate-unit>
   <police>
   <rate>
   <cir>{$RATE_MBS}</cir>
   <cir-unit>mbps</cir-unit>
   </rate>
   </police>
   </police-rate-unit>
   </class-default>
   </class>
   </policy-map>
   </config>
   </ned-id>
   </template>
   </devices>
   

Importing and Validating Templates

1. Save and import your new XML template into NSO using NSO web UI or CLI. This step allows you to load merge the custom templates to NSO before applying them.

   a. If using NSO CLI, load merge the template to NSO as follows:

   admin@ncs% load merge user-device-template.xml
   [ok]
   admin@ncs%
   commit [ok]
   

   For details on applying custom templates, refer to Using Custom-Templates – CFP Services in the Cisco NSO Transport SDN Function Pack Bundle 7.0.0 User Guide.

   b. When importing through the Web UI, use the Load/Save option and click Paste to load data by pasting it. The new changes must also be applied using Commit to apply the configuration.

2. Validate the new template in NSO.

   admin@ncs# show running-config devices template ?
   Description: Named configuration templates for devices
   Possible completions:
   CT-DEVICE-TEMPLATE The name of a specific template configuration.
   CT-PM-INPUT The name of a specific template configuration.
   CT-TEMPLATE-INPUT The name of a specific template configuration.
   CT-TEMPLATE2-INPUT The name of a specific template configuration.
   CT-SKELETON-POLICY The name of a specific template configuration.
   CT-TEMPLATE3-INPUT The name of a specific template configuration.
   <cr>
   Description: Named configuration templates for devices
   

Applying Templates to Services

1. Let's add this template to the L2VPN service in the Crosswork Network Controller.

   a. Choose Services & Traffic Engineering > Provisioning (NSO) > L2VPN > L2VPN-Service

   b. Click ▶️ to create a new service. The L2VPN-Service page is displayed.

   c. Enter a name for the VPN Identifier and click Continue.

   d. Under Custom-templates, click ➕ to apply your custom template. The Crosswork Network Controller will display your custom template for selection.

   e. Select your custom template and apply the required variables. Click Commit changes. Note that the router validation shows the policy map name and the police rate of 250 Mbps.

   Example UI Snippet:

   (Image description: A screenshot showing the L2VPN service configuration screen in Crosswork Network Controller. It displays fields for VPN ID, VPN type, and a section for Custom templates where various template names like CT-DEVICE-TEMPLATE, CT-PM-INPUT, etc., are listed. A selected template, CT-PM-INPUT, is highlighted, and its associated variables, RATE_MBS and POLICY_VAR, are shown with their values.)

   Example UI Snippet with Variables:

   (Image description: Another screenshot of the L2VPN service configuration, focusing on the custom template variables. The template CT-PM-INPUT is selected, and the variables RATE_MBS and POLICY_VAR are displayed with input fields for their values. The values shown are '250' for RATE_MBS and 'POLICYMAP_NAME' for POLICY_VAR.)

2. Repeat the process for adding the policy to the interfaces. Ensure to add the policy at the device level, as the interface numbers may be different on each side of the L2VPN.

   <config xmlns="http://tail-f.com/ns/config/1.0">
   <devices xmlns="http://tail-f.com/ns/ncs">
   <template>
   <name>CT-DEVICE-TEMPLATE</name>
   <ned-id>
   <id xmlns:cisco-iosxr-cli-7.52="http://tail-f.com/ns/ned-id/cisco-iosxr-cli-7.52">cisco-iosxr-cli-7.52:cisco-iosxr-cli-7.52</id>
   <config>
   <interface xmlns="http://tail-f.com/ned/cisco-ios-xr">
   <TenGigE-subinterface>
   <TenGigE>
   <id>{$INTERFACE}</id>
   <service-policy>
   <input>
   <name>{$SERVICE-POLICY}</name>
   </input>
   </service-policy>
   </TenGigE>
   </TenGigE-subinterface>
   </interface>
   </config>
   </ned-id>
   </template>
   </devices>
   </config>
   

For more examples of configuring custom templates, refer to Using Custom-Templates – CFP Services in the Cisco NSO Transport SDN Function Pack Bundle 7.1.0 User Guide.