Template

Templates provide a powerful way to define reusable configuration blocks that can be applied to multiple device groups or devices with different variable values. This is particularly useful for service-related configurations that need to be deployed repeatedly across different devices or environments with slight variations.

Templates support three different types:

• model: Configuration defined inline using the data model structure
• file: External template files (.tftpl) using Terraform templating syntax
• cli: Raw CLI commands for features not available in the data model

Configuration templates work by:

• Defining templates once
• Referencing templates by name at the global, device group, or device level
• Using global, device group, or device-level variables to populate template parameters
• Applying templates in the order specified

This approach promotes configuration consistency, reduces duplication, and simplifies management of similar services across your network infrastructure.

Diagram

Diagram

Classes

nxos

Name	Type	Constraint	Mandatory	Default Value
templates	List	templates	No

templates (nxos)

Name	Type	Constraint	Mandatory	Default Value
name	String		Yes
type	Choice	model, file, cli	Yes
stage	Choice	pre, post	No	post
order	Integer	min: 0, max: 9	No	0
file	String		No
content	String		No

templates (nxos)

Name	Type	Constraint	Mandatory	Default Value
name	String		Yes
type	Choice	model, file, cli	Yes
order	Integer	min: 0, max: 9	No	0
file	String		No
content	String		No

Template Types

Model Templates

Model templates define configuration inline using the standard data model structure. These are best for simple, self-contained configurations.

Example:

nxos:
  templates:
    - name: L2_SERVICE
      type: model
      configuration:
        vlan:
          vlans:
            - id: ${vlan_id}
              vn_segment: 10${vlan_id}
              name: L2_${vlan_id}
        interfaces:
          nve:
            vnis:
              - vni: 10${vlan_id}
                ingress_replication_protocol: bgp
        evpn:
          vnis:
            - vni: 10${vlan_id}
              rd: auto
              route_target_imports: ["65000:10${vlan_id}"]
              route_target_exports: ["65000:10${vlan_id}"]

Templating syntax can also be used within values of model templates, allowing you to reference variables directly in the configuration:

nxos:
  templates:
    - name: L2_SERVICE
      type: model
      configuration:
        vlan:
          vlans:
            - id: "${vlan_id}"
              vn_segment: 10${vlan_id}
              name: "L2_${site_name}_${vlan_id}"
        interfaces:
          nve:
            vnis:
              - vni: 10${vlan_id}
                ingress_replication_protocol: bgp
        evpn:
          vnis:
            - vni: 10${vlan_id}
              rd: auto
              route_target_imports: ${jsonencode(rt_imports)}
              route_target_exports: ${jsonencode(rt_exports)}

File Templates

File templates reference external .tftpl files that use Terraform templating syntax. These are ideal for complex configurations with dynamic content generation.

Template Definition:

nxos:
  templates:
    - name: standard_vlans
      type: file
      file: templates/vlans.yaml.tftpl

Template File Content (templates/vlans.yaml.tftpl):

vlan:
  vlans:
%{ for vlan in site_vlans }
    - id: ${vlan.id}
      name: "${vlan.name}"
%{ endfor }

Terraform Templating Syntax:

• %{ } - Control structures (for loops, if statements, etc.)
• ${ } - Variable interpolation
• ~ - Whitespace stripping

CLI Templates

CLI templates contain raw CLI commands for features that are not available in the data model. These are applied directly to the device.

CLI templates support an optional stage attribute to control whether they are applied before (pre) or after (post) the modeled configuration. The default stage is post. Use pre for configuration that the modeled configuration depends on.

CLI templates also support an optional order attribute (valid range: 0-9) to control the sequence in which templates are applied within a stage. Templates with lower order values are applied first. The default order is 0, meaning templates without an explicit order value are applied first. Templates with the same stage and order value may be applied in parallel.

Example:

nxos:
  templates:
    - name: GLOBAL_NTP
      type: cli
      order: 1
      content: |
        ntp server 10.50.100.1 use-vrf management
        ntp server 10.50.100.2 use-vrf management
        ntp source-interface mgmt0

Example: CLI template applied before the modeled configuration (e.g., interface MTUs)

nxos:
  templates:
    - name: JUMBO_MTU
      type: cli
      stage: pre
      content: |
        system jumbomtu 9216

Templating syntax can also be used within CLI templates, including control structures like loops:

nxos:
  templates:
    - name: NTP_SERVERS
      type: cli
      content: |
        %{ for server in ntp_servers }
        ntp server ${server} use-vrf management
        %{ endfor }

Template Application Levels

Templates can be applied at three different levels, providing flexibility in how configuration is deployed:

Global Level

Templates applied at the global level are inherited by all device groups and devices (unless overridden).

nxos:
  templates:
    - name: base_security
      type: model
      configuration:
        # ... configuration ...

  # Apply to all devices
  global:
    templates:
      - base_security

Device Group Level

Templates applied at the device group level affect all devices in that group.

nxos:
  device_groups:
    - name: LEAF_SWITCHES
      templates:
        - L2_SERVICE
        - L3_SERVICE

Device Level

Templates applied at the device level affect only that specific device, useful for device-specific configurations.

nxos:
  devices:
    - name: LEAF-01
      url: "https://10.1.1.1"
      templates:
        - GLOBAL_NTP
        - GLOBAL_LOGGING

Template Precedence

Template Inheritance and Merging

Templates are applied in the following order:

1. Global templates
2. Device group templates
3. Device-specific templates

Templates at each level are merged with templates from previous levels, allowing you to build configurations incrementally.

Variable Precedence

When templates are processed, variables are resolved in the following order (highest to lowest priority):

1. Device-level variables
2. Device group variables
3. Global variables

Template Type Selection

• Use model templates for straightforward configurations that map directly to the data model and only require templating of values
• Use file templates for complex configurations with loops, conditionals, or dynamic structures
• Use cli templates as a last resort, only for features not yet supported in the data model

Template Types

Model Templates

Model templates define configuration inline using the standard data model structure. These are best for simple, self-contained configurations.

Example:

nxos:
  templates:
    - name: L2_SERVICE
      type: model
      configuration:
        vlan:
          vlans:
            - id: ${vlan_id}
              vn_segment: 10${vlan_id}
              name: L2_${vlan_id}
        interfaces:
          nve:
            vnis:
              - vni: 10${vlan_id}
                ingress_replication_protocol: bgp
        evpn:
          vnis:
            - vni: 10${vlan_id}
              rd: auto
              route_target_imports: ["65000:10${vlan_id}"]
              route_target_exports: ["65000:10${vlan_id}"]

Templating syntax can also be used within values of model templates, allowing you to reference variables directly in the configuration:

nxos:
  templates:
    - name: L2_SERVICE
      type: model
      configuration:
        vlan:
          vlans:
            - id: "${vlan_id}"
              vn_segment: 10${vlan_id}
              name: "L2_${site_name}_${vlan_id}"
        interfaces:
          nve:
            vnis:
              - vni: 10${vlan_id}
                ingress_replication_protocol: bgp
        evpn:
          vnis:
            - vni: 10${vlan_id}
              rd: auto
              route_target_imports: ${jsonencode(rt_imports)}
              route_target_exports: ${jsonencode(rt_exports)}

File Templates

File templates reference external .tftpl files that use Terraform templating syntax. These are ideal for complex configurations with dynamic content generation.

Template Definition:

nxos:
  templates:
    - name: standard_vlans
      type: file
      file: templates/vlans.yaml.tftpl

Template File Content (templates/vlans.yaml.tftpl):

vlan:
  vlans:
%{ for vlan in site_vlans }
    - id: ${vlan.id}
      name: "${vlan.name}"
%{ endfor }

Terraform Templating Syntax:

• %{ } - Control structures (for loops, if statements, etc.)
• ${ } - Variable interpolation
• ~ - Whitespace stripping

CLI Templates

CLI templates contain raw CLI commands for features that are not available in the data model. These are applied directly to the device.

CLI templates support an optional order attribute (valid range: 0-9) to control the sequence in which templates are applied. Templates with lower order values are applied first. The default order is 0, meaning templates without an explicit order value are applied first. Templates with the same order value may be applied in parallel.

Example:

nxos:
  templates:
    - name: GLOBAL_NTP
      type: cli
      order: 1
      content: |
        ntp server 10.50.100.1 use-vrf management
        ntp server 10.50.100.2 use-vrf management
        ntp source-interface mgmt0

Templating syntax can also be used within CLI templates, including control structures like loops:

nxos:
  templates:
    - name: NTP_SERVERS
      type: cli
      content: |
        %{ for server in ntp_servers }
        ntp server ${server} use-vrf management
        %{ endfor }

Template Application Levels

Templates can be applied at three different levels, providing flexibility in how configuration is deployed:

Global Level

Templates applied at the global level are inherited by all device groups and devices (unless overridden).

nxos:
  templates:
    - name: base_security
      type: model
      configuration:
        # ... configuration ...

  # Apply to all devices
  global:
    templates:
      - base_security

Device Group Level

Templates applied at the device group level affect all devices in that group.

nxos:
  device_groups:
    - name: LEAF_SWITCHES
      templates:
        - L2_SERVICE
        - L3_SERVICE

Device Level

Templates applied at the device level affect only that specific device, useful for device-specific configurations.

nxos:
  devices:
    - name: LEAF-01
      url: "https://10.1.1.1"
      templates:
        - GLOBAL_NTP
        - GLOBAL_LOGGING

Template Precedence

Template Inheritance and Merging

Templates are applied in the following order:

1. Global templates
2. Device group templates
3. Device-specific templates

Templates at each level are merged with templates from previous levels, allowing you to build configurations incrementally.

Variable Precedence

When templates are processed, variables are resolved in the following order (highest to lowest priority):

1. Device-level variables
2. Device group variables
3. Global variables

Template Type Selection

• Use model templates for straightforward configurations that map directly to the data model and only require templating of values
• Use file templates for complex configurations with loops, conditionals, or dynamic structures
• Use cli templates as a last resort, only for features not yet supported in the data model