Day-23.md

Day 23: gNMI Set RPC for Configuration

Introduction:

Using the Set RPC to configure devices. Understanding Update, Replace, and Delete operations. Building SetRequest messages.

Code Example: Configuring a Loopback Interface via gNMI

// gnmi_set_loopback.go
package main

import (
	"context"
	"fmt"
	"os"

	"github.com/openconfig/gnmic/pkg/api"
	"google.golang.org/protobuf/encoding/prototext"
)

const (
	targetAddress = "172.20.20.2:6030" // Replace with your cEOS container IP and gNMI port
	username      = "admin"
	password      = "admin"
)

func main() {
	target, err := api.NewTarget(
		api.Address(targetAddress),
		api.Username(username),
		api.Password(password),
		api.SkipVerify(false),
		api.Insecure(true),
	)
	if err != nil {
		fmt.Println(err, "failed to create gnmi client")
		os.Exit(1)
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// create a gNMI client
	err = target.CreateGNMIClient(ctx)
	if err != nil {
		fmt.Println(err, "failed to create gnmi client")
		os.Exit(1)
	}
	defer target.Close()

	// create a gNMI SetRequest
	var updates []api.GNMIOption

	updates = append(updates, api.Update(
		api.Path("/system/config/hostname"),
		api.Value("ceos0000001", "json_ietf"),
	))

	setReq, err := api.NewSetRequest(updates...)

	if err != nil {
		fmt.Println(err, "failed to create Set request")
		os.Exit(1)
	}

	// send the created gNMI SetRequest to the created target
	setResp, err := target.Set(ctx, setReq)
	if err != nil {
		fmt.Println(err, "failed to send Set request")
		fmt.Println(prototext.Format(setResp))
		os.Exit(1)
	}

	fmt.Printf("gNMI Set Response: %s", prototext.Format(setResp))
}

Challenge 23 A:

1. Deploy a fresh cEOS lab instance.
2. Write a Go program using gNMI Set to configure an Ethernet2 interface with an IP address (e.g., 10.20.0.1/24) and enable it.
3. After the Set operation, use goeapi (from Module 3) or a gNMI Get request (from Day 22) to verify that the Ethernet2 interface has been configured correctly on the cEOS device.

Challenge 23 B:

1. Deploy the srl-2-nodes.clab.yaml
2. Set the description of Interface Ethernet-0/0 to Written via GNMI
3. Check with a gnmi GET or manually via SSH/CLI