Skip to content

Latest commit

 

History

History

3-hub-spoke-nva-single-region

README.md

Hub and Spoke - Dual Region

Lab: Hs13

Contents

Overview

This terraform code deploys a single-region standard Virtual Network (Vnet) hub and spoke topology using Virtual Network Appliances (NVA) in the hub.

Hub and Spoke (Single region)

Hub1 has an Azure Route Server (ARS) with BGP session to a Network Virtual Appliance (NVA) using a Cisco-CSR-100V router. The direct spokes Spoke1 and Spoke2 have Vnet peering to Hub1. An isolated Spoke3 does not have Vnet peering to the `Hub1``, but is reachable from the hub via Private Link Service.

Branch1 is the on-premises networks which is simulated using Vnet. A Multi-NIC Cisco-CSR-1000V NVA appliance connects to the Vnet hub using IPsec VPN connections with dynamic (BGP) routing.

Prerequisites

Ensure you meet all requirements in the prerequisites before proceeding.

Deploy the Lab

  1. Clone the Git Repository for the Labs
git clone https://github.com/kaysalawu/azure-network-terraform.git
  1. Navigate to the lab directory
cd azure-network-terraform/1-hub-and-spoke/3-hub-spoke-nva-single-region
  1. Run the following terraform commands and type yes at the prompt:
terraform init
terraform plan
terraform apply

Troubleshooting

See the troubleshooting section for tips on how to resolve common issues that may occur during the deployment of the lab.

Testing

Each virtual machine is pre-configured with a shell script to run various types of tests. Serial console access has been configured for all virtual mchines. You can access the serial console of a virtual machine from the Azure portal.

Login to virtual machine Hs13-spoke1-vm via the serial console.

  • username = azureuser
  • password = Password123

Hs13-spoke1-vm

Run the following tests from inside the serial console.

1. Ping IP

This script pings the IP addresses of some test virtual machines and reports reachability and round trip time.

Run the IP ping test

ping-ip

Sample output

azureuser@Hs13-spoke1-vm:~$ ping-ip

 ping ip ...

branch1 - 10.10.0.5 -OK 14.111 ms
hub1    - 10.11.0.5 -OK 2.538 ms
spoke1  - 10.1.0.5 -OK 0.043 ms
spoke2  - 10.2.0.5 -OK 3.009 ms
internet - icanhazip.com -NA

2. Ping DNS

This script pings the DNS name of some test virtual machines and reports reachability and round trip time.

Run the DNS ping test

ping-dns

Sample output

azureuser@Hs13-spoke1-vm:~$ ping-dns

 ping dns ...

vm.branch1.corp - 10.10.0.5 -OK 7.100 ms
vm.hub1.az.corp - 10.11.0.5 -OK 2.085 ms
vm.spoke1.az.corp - 10.1.0.5 -OK 0.040 ms
vm.spoke2.az.corp - 10.2.0.5 -OK 4.382 ms
icanhazip.com - 104.18.115.97 -NA

3. Curl DNS

This script uses curl to check reachability of web server (python Flask) on the test virtual machines. It reports HTTP response message, round trip time and IP address.

Run the DNS curl test

curl-dns

Sample output

azureuser@Hs13-spoke1-vm:~$ curl-dns

 curl dns ...

200 (0.057189s) - 10.10.0.5 - vm.branch1.corp
200 (0.027151s) - 10.11.0.5 - vm.hub1.az.corp
200 (0.023730s) - 10.11.4.4 - pep.hub1.az.corp
200 (0.017258s) - 10.1.0.5 - vm.spoke1.az.corp
[ 4471.136340] cloud-init[1527]: 10.1.0.5 - - [17/Sep/2023 14:34:19] "GET / HTTP/1.1" 200 -
200 (0.025640s) - 10.2.0.5 - vm.spoke2.az.corp
000 (2.000986s) -  - vm.spoke3.az.corp
200 (0.017255s) - 104.18.114.97 - icanhazip.com

We can see that spoke3 vm.spoke3.az.corp returns a 000 HTTP response code. This is expected as there is no Vnet peering to Spoke3 from Hub1. But Spoke3 web application is reachable via Private Link Service private endpoint pep.hub1.az.corp. The same explanation applies to Spoke6 virtual machine vm.spoke6.az.corp

4. Private Link Service

Test access to Spoke3 application using the private endpoint in Hub1.

curl pep.hub1.az.corp

Sample output

azureuser@Hs13-spoke1-vm:~$ curl pep.hub1.az.corp
{
  "headers": {
    "Accept": "*/*",
    "Host": "pep.hub1.az.corp",
    "User-Agent": "curl/7.68.0"
  },
  "hostname": "Hs13-spoke3-vm",
  "local-ip": "10.3.0.5",
  "remote-ip": "10.3.3.4"
}

The hostname and local-ip fields belong to the servers running the web application - in this case Spoke3 virtual machine. The remote-ip field (as seen by the web servers) is an IP addresses in the Private Link Service NAT subnet.

5. Network Virtual Appliance (NVA)

  1. Run a tracepath to vm.spoke2.az.corp (10.2.0.5) to observe the traffic flow through the NVA.
tracepath vm.spoke2.az.corp

Sample output

azureuser@Hs13-spoke1-vm:~$ tracepath vm.spoke2.az.corp
 1?: [LOCALHOST]                      pmtu 1500
 1:  10.11.1.9                                            41.160ms
 1:  10.11.1.9                                             1.423ms
 2:  10.2.0.5                                              4.598ms reached
     Resume: pmtu 1500 hops 2 back 2

We can observe the traffic flow from Spoke1 to Spoke2 goes through the NVA in Hub1 (IP address 10.11.1.9) before reaching the destination Spoke2 (10.2.0.5).

Repeat steps 1-5 for all other spoke and branch virtual machines.

6. Onprem Routes

Let's login to the onprem router Hs13-branch1-nva and observe its dynamic routes.

  1. Login to virtual machine Hs13-branch1-nva via the serial console.
  2. Enter username and password
    • username = azureuser
    • password = Password123
  3. Enter the Cisco enable mode
enable
  1. Display the routing table
show ip route

Sample output

Hs13-branch1-nva-vm#show ip route
...
[Truncated for brevity]
...
Gateway of last resort is 10.10.1.1 to network 0.0.0.0

S*    0.0.0.0/0 [1/0] via 10.10.1.1
      10.0.0.0/8 is variably subnetted, 14 subnets, 4 masks
B        10.1.0.0/16 [20/0] via 10.11.7.4, 00:37:33
B        10.2.0.0/16 [20/0] via 10.11.7.4, 00:37:33
S        10.10.0.0/24 [1/0] via 10.10.2.1
C        10.10.1.0/24 is directly connected, GigabitEthernet1
L        10.10.1.9/32 is directly connected, GigabitEthernet1
C        10.10.2.0/24 is directly connected, GigabitEthernet2
L        10.10.2.9/32 is directly connected, GigabitEthernet2
C        10.10.10.0/30 is directly connected, Tunnel0
L        10.10.10.1/32 is directly connected, Tunnel0
C        10.10.10.4/30 is directly connected, Tunnel1
L        10.10.10.5/32 is directly connected, Tunnel1
B        10.11.0.0/16 [20/0] via 10.11.7.4, 00:37:33
S        10.11.7.4/32 is directly connected, Tunnel0
S        10.11.7.5/32 is directly connected, Tunnel1
      168.63.0.0/32 is subnetted, 1 subnets
S        168.63.129.16 [254/0] via 10.10.1.1
      169.254.0.0/32 is subnetted, 1 subnets
S        169.254.169.254 [254/0] via 10.10.1.1
      192.168.10.0/32 is subnetted, 1 subnets
C        192.168.10.10 is directly connected, Loopback0
  1. Display BGP information
show ip bgp

Sample output

Hs13-branch1-nva-vm#show ip bgp
BGP table version is 5, local router ID is 192.168.10.10
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
              t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *    10.1.0.0/16      10.11.7.5                              0 65515 i
 *>                    10.11.7.4                              0 65515 i
 *    10.2.0.0/16      10.11.7.5                              0 65515 i
 *>                    10.11.7.4                              0 65515 i
 *>   10.10.0.0/24     10.10.2.1                0         32768 i
 *    10.11.0.0/16     10.11.7.5                              0 65515 i
 *>                    10.11.7.4                              0 65515 i

Cleanup

  1. Make sure you are in the lab directory
cd azure-network-terraform/1-hub-and-spoke/3-hub-spoke-nva-single-region
  1. Delete the resource group to remove all resources installed.
    Run the following Azure CLI command:
az group delete -g Hs13RG --no-wait