Cumulus - Create a Two-Leaf, Two-Spine Topology

Source: https://docs.cumulusnetworks.com/display/VX/Create+a+Two-Leaf%2C+Two-Spine+Topology

 

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• Created by Tom Wells, last modified by Ania Rolland on Jan 11, 2018

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The following sections describe how to configure network interfaces and FRRouting for a two-leaf/two-spine Cumulus VX network topology:

• Two spine VMs that represent two spine (aggregation layer) switches on the network.
• Two leaf VMs that represent two leaf (access layer) switches on the network.
  
   

These instructions assume that you have installed the relevant images and hypervisors, created four VMs with appropriate names, and that the VMs are running. Refer to the Getting Started chapter of this guide for more information on setting up the VMs.

Contents

• Configure CumulusVX-leaf1
• Configure the Remaining VMs
• Create Point-to-Point Connections Between VMs
• Test the Network Topology Connections

Configure CumulusVX-leaf1

You can configure each of the VMs using the Network Command Line Utility (NCLU) or by editing the /etc/network/interfaces and /etc/frr/frr.conf files as the sudo user.

The following configuration uses unnumbered IP addressing, where you use the same /32 IPv4 address on multiple ports. OSPF unnumbered doesn't have an equivalent to RFC-5549, so you need to use an IPv4 address to bring up the adjacent OSPF neighbors, allowing you to reuse the same IP address. You can see some example unnumbered OSPF configurations in the knowledge base.

To configure CumulusVX-leaf1:

1. Log into the CumulusVX-leaf1 VM using the default credentials:
   
   • username: cumulus
   • password: CumulusLinux!
2. As the sudo user, edit the /etc/frr/daemons file in a text editor. Set zebra, bgpd, and ospfd to yes, and save the file.
   

   zebra=yes bgpd=yes ospfd=yes ...

3. Run the following commands to configure the switch:
   

   cumulus@switch:~$ net add loopback lo ip address 10.2.1.1/32 cumulus@switch:~$ net add interface swp1 ip address 10.2.1.1/32 cumulus@switch:~$ net add interface swp2 ip address 10.2.1.1/32 cumulus@switch:~$ net add interface swp3 ip address 10.4.1.1/24 cumulus@switch:~$ net add interface swp1 ospf network point-to-point cumulus@switch:~$ net add interface swp2 ospf network point-to-point cumulus@switch:~$ net add ospf router-id 10.2.1.1 cumulus@switch:~$ net add ospf network 10.2.1.1/32 area 0.0.0.0 cumulus@switch:~$ net add ospf network 10.4.1.0/24 area 0.0.0.0 cumulus@switch:~$ net pending cumulus@switch:~$ net commit

   These commands configure both /etc/network/interfaces and /etc/frr/frr.conf. The output of each file is shown below.
   
   To edit the configuration files directly as the sudo user, copy the configurations below.
   /etc/network/interfaces

   # The loopback network interface auto lo   iface lo inet loopback   address 10.2.1.1/32   # The primary network interface auto eth0   iface eth0 inet dhcp   auto swp1   iface swp1   address 10.2.1.1/32   auto swp2   iface swp2   address 10.2.1.1/32   auto swp3   iface swp3   address 10.4.1.1/24

   /etc/frr/frr.conf

   service integrated-vtysh-config   interface swp1   ip ospf network point-to-point   interface swp2   ip ospf network point-to-point   router-id 10.2.1.1   router ospf   ospf router-id 10.2.1.1   network 10.2.1.1/32 area 0.0.0.0   network 10.4.1.0/24 area 0.0.0.0

4. Restart the networking service:
   

   cumulus@switch:~$ sudo systemctl restart networking

5. Restart FRRouting:
   

   cumulus@switch:~$ sudo systemctl restart frr.service

Configure the Remaining VMs

The configuration steps for CumulusVX-leaf2, CumulusVX-spine1, and CumulusVX-spine2 are the same as CumulusVX-leaf1; however, the file configurations are different. Listed below are the configurations for each additional VM:

• CumulusVX-leaf2:
  
  /etc/network/interfaces

  # The loopback network interface auto lo   iface lo inet loopback   address 10.2.1.2/32   # The primary network interface auto eth0   iface eth0 inet dhcp   auto swp1   iface swp1   address 10.2.1.2/32   auto swp2   iface swp2   address 10.2.1.2/32   auto swp3   iface swp3   address 10.4.2.1/24

  /etc/frr/frr.conf

  service integrated-vtysh-config   interface swp1   ip ospf network point-to-point   interface swp2   ip ospf network point-to-point   router-id 10.2.1.2   router ospf   ospf router-id 10.2.1.2                                                             network 10.2.1.2/32 area 0.0.0.0    network 10.4.2.0/24 area 0.0.0.0

• CumulusVX-spine1:
  
  /etc/network/interfaces

  # The loopback network interface auto lo   iface lo inet loopback   address 10.2.1.3/32   # The primary network interface auto eth0   iface eth0 inet dhcp   auto swp1   iface swp1   address 10.2.1.3/32   auto swp2   iface swp2   address 10.2.1.3/32   auto swp3   iface swp3

  /etc/frr/frr.conf

  service integrated-vtysh-config   interface swp1   ip ospf network point-to-point   interface swp2   ip ospf network point-to-point   router-id 10.2.1.3   router ospf   ospf router-id 10.2.1.3   network 10.2.1.3/32 area 0.0.0.0

• CumulusVX-spine2:
  
  /etc/network/interfaces

  # The loopback network interface auto lo   iface lo inet loopback   address 10.2.1.4/32   # The primary network interface auto eth0   iface eth0 inet dhcp   auto swp1   iface swp1   address 10.2.1.4/32   auto swp2   iface swp2   address 10.2.1.4/32   auto swp3   iface swp3

  /etc/frr/frr.conf

  service integrated-vtysh-config   interface swp1   ip ospf network point-to-point   interface swp2   ip ospf network point-to-point   router-id 10.2.1.4   router ospf   ospf router-id 10.2.1.4   network 10.2.1.4/32 area 0.0.0.0

Restart the networking and FRRouting services on all VMs before continuing.

Create Point-to-Point Connections Between VMs

To use the two-leaf/two-spine Cumulus VX network topology you configured above, you need to configure the network adapter settings for each VM to create point-to-point connections. The following example shows how to create point-to-point connections between each VM in VirtualBox. If you are not using VirtualBox, refer to your hypervisor documentation to configure network adapter settings.
Follow these steps for each of the four VMs.

Make sure that the VM is powered off.

1. In the VirtualBox Manager window, select the VM.
2. Click Settings, then click Network.
3. Click Adapter 2.
4. Click the Enable Network Adapter check box.
5. From the Attached to list, select Internal Network.
   
6. In the Name field, type a name for the internal network, then click OK.
   The internal network name must match the internal network name on the corresponding network adapter on the VM to be connected to this VM. For example, in the two-leaf/two-spine Cumulus VX network topology, Adapter 2 (swp1) on CumulusVX-leaf1 is connected to Adapter 2 (swp1) on CumulusVX-spine1; the name must be the same for Adapter 2 on both VMs. Use the internal network names and the connections shown in the illustration and table below.
7. Click Adapter 3 and repeat steps 4 thru 6. Use the internal network names and the connections shown in the illustration and table below.

CumulusVX-leaf1		Adapter 1	NAT
	swp1	Adapter 2	Internal	Intnet-1
	swp2	Adapter 3	Internal	Intnet-3
	swp3	Adapter 4	Internal	Intnet-5
CumulusVX-leaf2		Adapter 1	NAT
	swp1	Adapter 2	Internal	Intnet-2
	swp2	Adapter 3	Internal	Intnet-4
	swp3	Adapter 4	Internal	Intnet-6
CumulusVX-spine1		Adapter 1	NAT
	swp1	Adapter 2	Internal	Intnet-1
	swp2	Adapter 3	Internal	Intnet-2
	swp3	Adapter 4 (disabled)
CumulusVX-spine2		Adapter 1	NAT
	swp1	Adapter 2	Internal	Intnet-3
	swp2	Adapter 3	Internal	Intnet-4
	swp3	Adapter 4 (disabled)

Test the Network Topology Connections

After you restart the VMs, ping across VMs to test the connections:

1. Run the following commands from CumulusVX-leaf1:
   
   • Ping CumulusVX-leaf2:
     

     cumulus@CumulusVX-leaf1:~$ ping 10.2.1.2

   • Ping CumulusVX-spine1:
     

     cumulus@CumulusVX-leaf1:~$ ping 10.2.1.3

   • Ping CumulusVX-spine2:
     

     cumulus@CumulusVX-leaf1:~$ ping 10.2.1.4