Custom Configuration Snippets

Overview

Netris lets administrators deploy custom switch configurations using configuration snippets.

Snippets are plain-text configuration fragments that merge into the configuration the Netris agent generates before applying it to the switch.

Configuration snippets are supported on switches running Arista EOS and NVIDIA Cumulus Linux (NVUE).

Tip

Snippets become part of the enforced configuration. The Netris agent treats the combined configuration — the agent-generated configuration plus your snippets — as the switch’s desired state. Each agent run reconciles the switch against this combined configuration, so snippet-provided settings are maintained on an ongoing basis, the same way agent-managed settings are.

Warning

Test snippets before applying them broadly. Snippet content is appended after the agent-generated configuration and, in most cases, takes precedence for the specific settings it defines. The exact outcome depends on how the switch resolves concurrent configuration for those commands — some settings merge, others override — so behavior can vary by platform and by the specific configuration involved.

Include every dependency your snippet needs, and validate the combined configuration in a low-impact environment before rolling it out more broadly.

Tip

Because snippets live only on the switch and aren’t tracked by the controller, plan to reapply your snippet files whenever you reprovision a switch.

Arista EOS

The Netris agent creates a dedicated directory on the switch for snippets:

/mnt/flash/netris-snippets

Selection rules:

  1. Only files whose name contains .conf are included. Anything else in the directory — other files, subdirectories, sockets, devices, or editor leftovers like foo.conf~ — is ignored. Selection is by filename only.

  2. Files are read in filename sort order, so use a naming convention — such as a numeric prefix — to control merge order of multiple snippet files: 00-snippet.conf, 01-snippet.conf, etc.

  3. Snippet contents are appended to the end of the generated new_config.conf, before the trailing END, in that sort order — after the agent-generated configuration.

Example:

  1. Determine the desired EOS configuration. For example,

management api http-commands
   vrf default
      no shutdown

  1. Save it as a file under /mnt/flash/netris-snippets/ using the numeric-prefix convention — for example, /mnt/flash/netris-snippets/00-api-http-commands.conf.

  2. On the next agent run, this fragment is appended to the end of new_config.conf (before END) and applied to the switch along with the agent-generated configuration.

NVIDIA Cumulus Linux (NVUE)

The Netris agent creates and manages a directory on the switch that holds the switch’s full configuration, generated locally based on the intent defined on the controller:

/opt/netris/etc/nvue/

Tip

This directory holds the agent’s own configuration files alongside your snippet files — add your snippets into this same directory.

Selection rules:

  1. Only files with a .yaml extension are considered. Anything else in the directory is ignored.

  2. Files are read in filename sort order, so use a naming convention — such as a numeric prefix — to control merge order among multiple snippet files: 00-snippet.yaml, 01-snippet.yaml, etc.

  3. Snippet contents are merged into the agent-generated configuration in that sort order.

Example:

  1. Stage the desired configuration using NVUE commands:

nv set system snmp-server state enabled
nv set system snmp-server listening-address all vrf mgmt
nv set system snmp-server listening-address all-v6 vrf mgmt
nv set system snmp-server readonly-community clear_text access any

  1. Retrieve the YAML version of the configuration diff:

nv config diff

- set:
   system:
     snmp-server:
       listening-address:
         all:
           vrf: mgmt
         all-v6:
           vrf: mgmt
       readonly-community:
         $nvsec$bc2dea2ea717f9e9aef0265a8f09f949:
           access:
             any: {}
       state: enabled

  1. Create a file under /opt/netris/etc/nvue/ with the YAML content retrieved in step 2, using the numeric-prefix convention. For example, create the file /opt/netris/etc/nvue/50-snmp.yaml with the content above.

  2. Check that the configuration in the file is correct:

nv config patch /opt/netris/etc/nvue/<file>
nv config diff

  1. Check for any configuration errors by applying it manually:

nv config apply