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Build Containerlab topology from AVD

Posted 2022-02-04 Updated 2022-02-04 11 min read

Overview

Until recently, if we want to do networking lab, we had option to play with GNS3 or EVE-NG with Virtual Machine for Network OS. But 2021 has seen the rise of Containerlab which gives us ability to play Lab As Code as you can define your own topology in a YAML file.

Arista cEOS is natively supported by the tool and gives you opportunity to build lab easily from any type of tool in charge of your design. Big thanks you to Nokia’s team for making this tool fully open-source and with support for all NOS.

In this article, we will see how to build a containerlab topology from an Arista Validated Design collection for ansible where you define your EVPN topology.

Yes, with AVD, you can easily build any type of EVPN/VXLAN fabric, but at some point it is nice to test configuration and building topology on the fly would make design easier.

Of course, you can also find some containerlab examples with Arista cEOS on github, but here we are going to talk about generating lab from Ansible.

AVD to design an EVPN fabric

This guide is not a detailed guide to setup Arista AVD collection. For this type of document, you should visit specific documentation for that. Here we will build a basic L3LS EVPN fabric based on 2 spines, 4 groups of 2 vteps and some L2 edge switches.

AVD Topology

Install environment

Here we are talking about python for ansible and Golang for Containerlab. And obviously, you need a docker engine to bring up lab at the end.

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# Download AVD requirements
$ curl -fsSL https://raw.githubusercontent.com/aristanetworks/ansible-avd/devel/ansible_collections/arista/avd/requirements.txt
$ pip3 install -r requirements.txt

# Install ansible
$ pip3 install ansible-core

Once ansible is installed, you can use galaxy to install AVD and avd_to_containerlab role:

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$ ansible-galaxy collection install arista.avd
$ ansible-galaxy collection install titom73.avd_tools

Now we can install Containerlab:

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$ bash -c "$(curl -sL https://get-clab.srlinux.dev)"

Since we are here, let’s download a cEOS version from Arista website. For that, you can use eos-download as explained in this post. And finally, install it on your Machine.

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$ docker import cEOS-lab.tar.xz ceosimage:<your-ceos-version>

Now we are ready to go to the build phase.

Ansible configuration

Topology file is provided below and will be the key to build containerlab topology

  • Spine topology:
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spine:
  defaults:
    platform: vEOS-LAB
    bgp_as: 65001
    loopback_ipv4_pool: 192.168.1.0/24
    bgp_defaults: ''
    mlag_peer_ipv4_pool: 172.31.253.0/31
    mlag_peer_l3_ipv4_pool: 172.31.253.2/31
  nodes:
    ceos-spine1:
      id: 1
      mgmt_ip: 10.73.255.101/24
      mac_address: '0c:1d:c0:1d:62:01'
    ceos-spine2:
      id: 2
      mgmt_ip: 10.73.255.102/24
      mac_address: '0c:1d:c0:1d:62:02'
  • vTEP (aka L3LEAF) topology
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l3leaf:
  defaults:
    loopback_ipv4_pool: 192.168.255.0/24
    loopback_ipv4_offset: 2
    vtep_loopback_ipv4_pool: 192.168.254.0/24
    uplink_interfaces: ['Ethernet1', 'Ethernet2']
    uplink_switches: ['ceos-spine1', 'ceos-spine2']
    uplink_ipv4_pool: 172.31.255.0/24
    evpn_route_servers: ['ceos-spine1', 'ceos-spine2']
    mlag_peer_ipv4_pool: 172.31.253.0/31
    mlag_peer_l3_ipv4_pool: 172.31.253.2/31
    mlag_interfaces: ''
    virtual_router_mac_address: 00:1c:73:00:dc:01
    bgp_defaults: ''
    spanning_tree_priority: 4096
    spanning_tree_mode: mstp
  node_groups:
    ceos_leaf1:
      bgp_as: 65101
      filter:
        tenants: [ 'Tenant_A', 'Tenant_B' ]
        tags: [ 'POD01', 'DC1' ]
      nodes:
        ceos-leaf1a:
          id: 11
          mgmt_ip: 10.73.255.111/24
          uplink_switch_interfaces: [Ethernet1, Ethernet1]
          mac_address: '0c:1d:c0:1d:62:11'
        ceos-leaf1b:
          id: 12
          mgmt_ip: 10.73.255.112/24
          uplink_switch_interfaces: [Ethernet2, Ethernet2]
          mac_address: '0c:1d:c0:1d:62:12'

# [ Output ommitted for readability]
# ...
  • L2 Switch (aka L2LEAF) topology
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edge:
  defaults:
    uplink_switches: ['ceos-leaf1a', 'ceos-leaf1b']
    uplink_interfaces: ['Ethernet1', 'Ethernet2']
    mlag_peer_ipv4_pool: 172.31.253.0/31
    mlag_peer_l3_ipv4_pool: 172.31.253.2/31
  node_groups:
    ceos_edge_leaf1:
      uplink_switches: [ ceos-leaf1a, ceos-leaf1b ]
      filter:
        tenants: [ 'Tenant_A', 'Tenant_B' ]
        tags: [ 'POD01', 'DC1' ]
      nodes:
        ceos-agg01:
          id: 21
          mgmt_ip: 10.73.255.121/24
          mac_address: '0c:1d:c0:1d:62:21'
          uplink_switch_interfaces: [ Ethernet5, Ethernet5 ]

# [ Output ommitted for readability]
# ...

For a complete list of options, it is better to read the full documentation of AVD.

Also, full inventory is available on github. So you can just clone and play.

Playbook

After inventory has been created, we can create a playbook. This one will be fairly easy and will do 3 things:

  • Transform abstracted topology into YAML EOS configuration file
  • Generate EOS Cli configuration file
  • Generate a containerlab topology loading AVD generated configuration files.

So here we go:

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# playbook/build.yml
---
- name: Build Switch configuration
  hosts: [all]
  tags:
    - avd
  collections:
    - arista.avd
  tasks:
    - name: generate intended variables
      tags: [build]
      import_role:
        name: eos_designs
    - name: generate device intended config and documentation
      tags: [build]
      import_role:
        name: eos_cli_config_gen

- name: Build containerlab topology
  hosts: [all]
  connection: local
  gather_facts: false
  collections:
    - arista.avd
    - titom73.avd_tools
  tasks:
    - name: 'Build Containerlab Topology'
      tags:
        - containerlab
      import_role:
        name: inetsix.avd_tools.eos_designs_to_containerlab
      vars:
        mgmt_network_v4: 10.73.255.0/24
        ceos_version: arista/ceos:4.27.1F
        eapi_base: 8000

As you can see, eos_designs_to_containerlab role needs some elements to generate a full configuration:

  • mgmt_network_v4: Management network to configure on docker side. It must be the same as the one used in AVD
  • eapi_base: Base port for eAPI to expose eAPI service to the network outside of docker.
  • ceos_version: Which version of cEOS to use.

Make the magic happens 

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$ ansible-playbook playbooks/containerlab-build.yml -i containerlab/inventory.yml
[...]
===============================================================================
arista.avd.eos_cli_config_gen : Generate content of device documentation ---------- 4.61s
arista.avd.eos_cli_config_gen : Generate eos intended configuration --------------- 3.30s
arista.avd.eos_designs : Generate device configuration in structured format ------- 1.75s
arista.avd.eos_cli_config_gen : Generate TOC for device documentation ------------- 0.92s
arista.avd.eos_designs : Write device structured configuration to YAML file ------- 0.85s
arista.avd.eos_designs : Generate fabric documentation in Markdown Format. -------- 0.72s
arista.avd.eos_cli_config_gen : Create required output directories if not present - 0.61s
arista.avd.eos_designs : Set AVD facts -------------------------------------------- 0.58s
arista.avd.eos_cli_config_gen : Store checksum of existing device documentation --- 0.50s
arista.avd.eos_designs : Generate TOC for fabric documentation -------------------- 0.47s
arista.avd.eos_designs : Generate fabric topology in csv format. ------------------ 0.46s
inetsix.avd_tools.eos_designs_to_containerlab : Generate containerlab topology ---- 0.45s
arista.avd.eos_designs : Create required output directories if not present -------- 0.44s
arista.avd.eos_designs : Set AVD topology facts ----------------------------------- 0.28s
arista.avd.eos_designs : Store checksum of existing fabric documentation ---------- 0.26s
Playbook run took 0 days, 0 hours, 0 minutes, 17 seconds

So now you can look at files generated:

  • EOS configuration files under intended/configs
  • Containerlab topology in containerlab/containerlab.yml
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---
name: ceos_fabric

mgmt:
  network: 'mgmt_ceos_fabric'
  ipv4_subnet: 10.73.255.0/24

topology:
  kinds:
    ceos:
      image: arista/ceos:4.27.1F
  nodes:
    ceos-agg01:
      image: arista/ceos:4.27.1F
      mgmt_ipv4: 10.73.255.121
      kind: ceos
      startup-config: <path>/intended/configs/ceos-agg01.cfg
      ports:
      - 8021:443/tcp
      env:
        TMODE: lacp
# [...]
 links:
    - endpoints: ["ceos-agg01:eth1", "ceos-leaf1a:eth5"]
# [...]

And you can start containerlab:

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$ sudo containerlab deploy --topo inventories/containerlab/containerlabs.yml
[sudo] password for tom:

INFO[0000] Parsing & checking topology file: containerlabs.yml
INFO[0000] Creating lab directory: /home/tom/arista-\
    avd/avd-lab-validation/clab-ceos_fabric
INFO[0000] Creating docker network: Name='mgmt_ceos_fabric', \
    IPv4Subnet='10.73.255.0/24', IPv6Subnet='', MTU='1500'
INFO[0000] config file '/home/tom/arista-avd/avd-lab-validation/\
    clab-ceos_fabric/ceos-agg01/flash/startup-config' for node \
    'ceos-agg01' already exists and will not be generated/reset
INFO[0000] Creating container: ceos-agg01
[...]
INFO[0004] Creating virtual wire: ceos-leaf3a:eth3 <--> ceos-leaf4a:eth3
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-leaf2a' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-bl01a' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-leaf3a' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-leaf4a' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-agg02' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-leaf1a' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-leaf2b' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-leaf1b' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-spine1' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-spine2' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-bl01b' node
INFO[0005] Running postdeploy actions for Arista cEOS 'ceos-agg01' node

Once it is over, you should see output below. It gives you some information such as kind, version and management 0 IP address.

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INFO[0143] 🎉 New containerlab version 0.23.0 is available! Release notes: https://containerlab.srlinux.dev/rn/0.23/
Run 'containerlab version upgrade' to upgrade or go check other installation options at https://containerlab.srlinux.dev/install/
+----+------------------------------+--------------+---------------------+------+---------+------------------+--------------+
| #  |             Name             | Container ID |        Image        | Kind |  State  |   IPv4 Address   | IPv6 Address |
+----+------------------------------+--------------+---------------------+------+---------+------------------+--------------+
|  1 | clab-ceos_fabric-ceos-agg01  | 37973cf400d7 | arista/ceos:4.27.1F | ceos | running | 10.73.255.121/24 | N/A          |
|  2 | clab-ceos_fabric-ceos-agg02  | cb37f8b37e0f | arista/ceos:4.27.1F | ceos | running | 10.73.255.122/24 | N/A          |
|  3 | clab-ceos_fabric-ceos-bl01a  | 9ba07822490b | arista/ceos:4.27.1F | ceos | running | 10.73.255.115/24 | N/A          |
|  4 | clab-ceos_fabric-ceos-bl01b  | 40eaf38dd58c | arista/ceos:4.27.1F | ceos | running | 10.73.255.116/24 | N/A          |
|  5 | clab-ceos_fabric-ceos-leaf1a | f4ac53c2ae4d | arista/ceos:4.27.1F | ceos | running | 10.73.255.111/24 | N/A          |
|  6 | clab-ceos_fabric-ceos-leaf1b | c03adbff83af | arista/ceos:4.27.1F | ceos | running | 10.73.255.112/24 | N/A          |
|  7 | clab-ceos_fabric-ceos-leaf2a | b59260c441a0 | arista/ceos:4.27.1F | ceos | running | 10.73.255.113/24 | N/A          |
|  8 | clab-ceos_fabric-ceos-leaf2b | 5514405b6429 | arista/ceos:4.27.1F | ceos | running | 10.73.255.114/24 | N/A          |
|  9 | clab-ceos_fabric-ceos-leaf3a | 87e22287c2f2 | arista/ceos:4.27.1F | ceos | running | 10.73.255.117/24 | N/A          |
| 10 | clab-ceos_fabric-ceos-leaf4a | 878b75601225 | arista/ceos:4.27.1F | ceos | running | 10.73.255.118/24 | N/A          |
| 11 | clab-ceos_fabric-ceos-spine1 | 7d10d85458e0 | arista/ceos:4.27.1F | ceos | running | 10.73.255.101/24 | N/A          |
| 12 | clab-ceos_fabric-ceos-spine2 | 7e0effa1ccd6 | arista/ceos:4.27.1F | ceos | running | 10.73.255.102/24 | N/A          |
+----+------------------------------+--------------+---------------------+------+---------+------------------+--------------+

Also, you can look at docker directly. This one is interesting to ge eAPI port mapping:

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docker ps
CONTAINER ID   IMAGE                  COMMAND                  CREATED         STATUS         PORTS                                       NAMES
87e22287c2f2   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8015->443/tcp, :::8015->443 tcp     clab-ceos_fabric-ceos-leaf3a
f4ac53c2ae4d   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8011->443/tcp, :::8011->443/tcp     clab-ceos_fabric-ceos-leaf1a
5514405b6429   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8014->443/tcp, :::8014->443/tcp     clab-ceos_fabric-ceos-leaf2b
40eaf38dd58c   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8018->443/tcp, :::8018->443/tcp     clab-ceos_fabric-ceos-bl01b
b59260c441a0   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8013->443/tcp, :::8013->443/tcp     clab-ceos_fabric-ceos-leaf2a
cb37f8b37e0f   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8022->443/tcp, :::8022->443/tcp     clab-ceos_fabric-ceos-agg02
c03adbff83af   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8012->443/tcp, :::8012->443/tcp     clab-ceos_fabric-ceos-leaf1b
7d10d85458e0   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8001->443/tcp, :::8001->443/tcp     clab-ceos_fabric-ceos-spine1
878b75601225   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8016->443/tcp, :::8016->443/tcp     clab-ceos_fabric-ceos-leaf4a
7e0effa1ccd6   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8002->443/tcp, :::8002->443/tcp     clab-ceos_fabric-ceos-spine2
37973cf400d7   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8021->443/tcp, :::8021->443/tcp     clab-ceos_fabric-ceos-agg01
9ba07822490b   arista/ceos:4.27.1F    "/sbin/init systemd.…"   2 minutes ago   Up 2 minutes   0.0.0.0:8017->443/tcp, :::8017->443/tcp     clab-ceos_fabric-ceos-bl01a

And you can connect to your EOS cli directly from host with docker command:

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docker exec -it clab-ceos_fabric-ceos-spine1 Cli
ceos-spine1>
ceos-spine1>en

ceos-spine1#show lldp neighbors
Last table change time   : 0:12:19 ago
Number of table inserts  : 20
Number of table deletes  : 1
Number of table drops    : 0
Number of table age-outs : 1

Port          Neighbor Device ID       Neighbor Port ID    TTL
---------- ------------------------ ---------------------- ---
Et1           ceos-leaf1a              Ethernet1           120
Et2           ceos-leaf1b              Ethernet1           120
Et3           ceos-leaf2a              Ethernet1           120
Et4           ceos-leaf2b              Ethernet1           120
Et5           ceos-bl01a               Ethernet1           120
Et6           ceos-bl01b               Ethernet1           120
Et7           ceos-leaf3a              Ethernet1           120
Et8           ceos-leaf4a              Ethernet1           120

ceos-spine1#show bgp evpn summary
BGP summary information for VRF default
Router identifier 192.168.1.1, local AS number 65001
Neighbor Status Codes: m - Under maintenance
  Description  Neighbor         V AS    MsgRcvd MsgSent InQ OutQ  Up/Down State  PfxRcd PfxAcc
  ceos-leaf1a  192.168.255.13   4 65101      46      42   0    0 00:13:01 Estab  10     10
  ceos-leaf1b  192.168.255.14   4 65101      46      42   0    0 00:13:01 Estab  10     10
  ceos-leaf2a  192.168.255.15   4 65102      51      41   0    0 00:13:07 Estab  10     10
  ceos-leaf2b  192.168.255.16   4 65102      52      42   0    0 00:13:08 Estab  10     10
  ceos-leaf3a  192.168.255.17   4 65103      52      44   0    0 00:13:16 Estab  5      5
  ceos-leaf4a  192.168.255.18   4 65104      53      48   0    0 00:13:28 Estab  5      5
  ceos-bl01a   192.168.255.19   4 65105      52      48   0    0 00:13:18 Estab  4      4
  ceos-bl01b   192.168.255.20   4 65105      54      48   0    0 00:13:18 Estab  4      4

If you change your AVD parameter, your lab will be fully rebuild and will be ready for testing. You just have to destroy active topology before running again the playbook.

Resources

Automation
ansible devops containerlab arista
This post is licensed under CC BY 4.0 by the author.
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