networkop / acb-oc

Intro

What is OpenConfig

• The OpenConfig Working Group is a group of network operators that defines a set of vendor-neutral data models for switch configuration and status
• The data models are expressed in YANG, a data modelling language
• The OpenConfig working group doesn’t mandate an API (or protocol) for client access
• The OpenConfig data model is accessed and manipulated over a choice of APIs; NETCONF (over SSH), gNMI (gRPC) and RESTCONF (HTTPS)

History

• Initially NETCONF, IETF group started 2003, first spec was RFC4741 Dec 2006
• YANG modelling language, IETF group started 2008, first spec was RFC6020 in Oct 2010
• Each vendor provided their own unique YANG models
• OpenConfig working group was established in 2014
• The working group published its first models including BGP in 2015

Pitch

• Better programmatic interface to config and status
• Better than the CLI for automated config management
• Better than SNMP for getting telemetry
  • Streaming, not polling!
• Models developed in the open by operators, with feedback from vendors
  • github.com/openconfig/public
• Allows for cross-vendor tools to develop
  • Where switches from different vendors are managed in the same way.
• Models are not from the usual standard bodies IETF, IEEE not involved
  • allows for rapid development of models

Customer Use Case

• Do all config with YANG models
  • Use OpenConfig models wherever defined
  • Fill in gaps with proprietary models when necessary, proprietary models may be auto-generated.
  • Common switch management, pushed to switches in a standard fashion.
• Stream telemetry using YANG model

Useful links

GNMI specification

OpenConfig YANG models

Arista OpenConfig YANG models

GNOI - file transfer, ping, traceroute, clear ARP/STP/LLDP/BGP

GRIBI

Demo

1. Setup

export CEOS_VERSION=ceos:4.21.5F

docker-compose up -d
docker inspect ceos-1 |  jq '.[0].NetworkSettings.Networks.oc_management.IPAddress'
docker inspect ceos-2 |  jq '.[0].NetworkSettings.Networks.oc_management.IPAddress'

2. Exploring YANG models

docker exec -it gnmi-client bash

GO111MODULE=on go build github.com/openconfig/goyang

git clone --depth 1 https://github.com/aristanetworks/yang arista
git clone --depth 1 https://github.com/YangModels/yang.git yang

./goyang --format tree --path ./arista/ --path ./yang/standard/ietf/ \
./arista/EOS-4.21.3F/openconfig/public/release/models/interfaces/* | more

3. Build Arista gNMI client

docker exec -it gnmi-client bash

GO111MODULE=on go build -o arista-gnmi github.com/aristanetworks/goarista/cmd/gnmi

4. Demonstrate gNMI client

./arista-gnmi -addr 172.20.0.2:6030 -password admin -username admin capabilities

./arista-gnmi -addr 172.20.0.2:6030 -password admin -username admin get /

./arista-gnmi -addr 172.20.0.2:6030 -password admin -username admin subscribe "/network-instances/network-instance[name=default]/protocols/protocol[identifier=BGP][name=BGP]/bgp/" &

./arista-gnmi -addr 172.20.0.2:6030 -username admin -password admin update "/interfaces/interface[name=Ethernet1]/config/enabled" "false"

./arista-gnmi -addr 172.20.0.2:6030 -username admin -password admin update "/interfaces/interface[name=Ethernet1]/config/enabled" "true"

Terraform demo

Link

1. Tmux-split the screen into three and start Cli sessions in two smaller screens, default interface Ethernet1

2. Open main.tf and provider.tf

cd ~/tf-yang
rm -f terraform.tfstate*        
code main.tf
code provider.tf

3. First configure L2 interface

resource "gnmi_interface" "SW1_Eth1" {
    provider = "gnmi.s1"
    name = "Ethernet1"
    description = "TF_INT_ETH1"
    switchport = true
    trunk_vlans = [100]
}
resource "gnmi_interface" "SW2_Eth1" {
    provider = "gnmi.s2"
    name = "Ethernet1"
    description = "TF_INT_ETH1"
    switchport = true
    access_vlan = 200
}

4. Next configure IPv4 interface

resource "gnmi_interface" "SW1_Eth1" {
    provider = "gnmi.s1"
    name = "Ethernet1"
    description = "TF_INT_ETH1"
    switchport = false
    ipv4_address = "12.12.12.1/24"
}
resource "gnmi_interface" "SW2_Eth1" {
    provider = "gnmi.s2"
    name = "Ethernet1"
    description = "TF_INT_ETH1"
    switchport = false
    ipv4_address = "12.12.12.2/24"
}

5. Examine the code

Cleanup

docker-compose down