Interconnect clusters through the vRack

Setting up a two-cluster interconnection through an OVHcloud vRack

Last updated 28th September 2022

Objective

This guide will show you how to interconnect two Nutanix clusters Provided by OVHcloud across the same vRack in two remote OVHcloud sites. In this guide, the connection is made between the Gravelines and Roubaix datacentres.

OVHcloud provides services for which you are responsible, with regard to their configuration and management. It is therefore your responsibility to ensure that they work properly.

This guide is designed to assist you as much as possible with common tasks. Nevertheless, we recommend contacting a specialist provider if you experience any difficulties or doubts when it comes to managing, using or setting up a service on a server.

Requirements

  • You must be logged in to your OVHcloud Control Panel.
  • You must be connected to your clusters via Prism Central.

Instructions

We are going to interconnect two remote Nutanix clusters, one in Gravelines and the other in Roubaix through the same vRack.
See our vRack overview to learn more about the OVHcloud vRack solution.

Preparing both clusters before interconnection

Before connecting the two clusters, ensure that they use different IP addresses (except for the gateway) on the same IP address range.
In our guide, we will use the address range 192.168.0.0/22.

The Gravelines cluster uses these addresses:

  • Server 1: CVM VM address 192.168.2.1, AHV hypervisor IP address 192.168.2.21.
  • Server 2: CVM VM address 192.168.2.2, AHV hypervisor IP address 192.168.2.22.
  • Server 3: CVM VM address '192.168.2.3', AHV hypervisor IP address 192.168.2.23.
  • Virtual address of Prism Element: 192.168.2.100.
  • Prism Central IP address:192.168.2.101.
  • Gateway: 192.168.2.254.
  • Cluster version: 6.1.

The Roubaix cluster uses these addresses:

  • Server 1: CVM VM address 192.168.1.1, AHV hypervisor IP address 192.168.1.21.
  • Server 2: CVM VM address 192.168.1.2, AHV hypervisor IP address 192.168.1.22.
  • Server 3: CVM VM address 192.168.1.3, AHV hypervisor IP address 192.168.1.23.
  • Virtual address of Prism Element: 192.168.1.100.
  • Prism Central IP address:192.168.1.101.
  • Gateway: 192.168.2.254.
  • Cluster version: 6.1.

Use our guide on customised redeployment of your Cluster.

The guide mentioned above will help you redeploy both clusters. However, you can only redeploy one, the most important thing is not to have the same identical IP addresses across the network, except for the OVHgateway.

Shutting down the OVHgateway virtual machine.

The outgoing internet connection is provided by OVHgateway virtual machines with the same private IP address on both sites. We will stop the OVHcloud Virtual Machine Gateway in Roubaix. This virtual machine will no longer be needed.

The outgoing internet connection will be restored when the connection through the vRack is made.

Log in to the cluster Prism Central interface located in Roubaix.

Go to the virtual machine management section, select OVHgateway from the Actions menu and click Guest Shutdown.

01 OVHgateway Shutdown 01

Access to Prism Central is maintained using the Load Balancer.

Configuring vRacks

This operation involves deleting the vRack assignment in Roubaix and then extending the vRack from Gravelines to Roubaix. You can modify the vRack via the OVHcloud Control Panel.

Log in to your OVHcloud Control Panel.

Deleting Roubaix vRack elements.

From the Hosted Private Cloud menu, select the Roubaix cluster on the left in the Nutanix category and note the name of the vRack which is under Private network (vRack).

02 Remove services from vrack 01

Go to the Bare Metal Cloud menu, click on the vRack concerned below the vRack option (in the Network submenu).

02 Remove services from vrack 02

Select all the elements that are in your vRack:

  • Dedicated servers
  • IPs
  • the Load Balancer

Write them down and click Remove

This operation may take a few minutes, please wait during this period.

02 Remove services from vrack 03

Adding deleted items from the Roubaix vRack into the Gravelines vRack

Go back to the Hosted Private Cloud menu, choose the Gravelines cluster from the Nutanix category and note the name of the vRack under Private network (vRack).

03 Add to vrack 01

Go to the Bare Metal Cloud menu, select the vRack from Gravelines below the vRack option (from the Network submenu).

03 Add to vrack 02

Select these elements from the Roubaix cluster:

  • Physical servers
  • the public IP.

Then click Add.

This operation may take a few minutes, please wait during this period.

Adding the public address is not mandatory but it will make it available for future needs.

03 Add to vrack 03

The vRack that was only used by the servers in the Gravelines cluster is now used on both sites and contains:

  • The physical servers of the two clusters.
  • The public IP addresses of the two clusters.
  • The Gravelines Load Balancer, used for Prism Central.

Outgoing internet access on the Roubaix website is again available through the vRack and the OVHgateway virtual machine in Gravelines. Access to Prism Central for the Roubaix cluster is currently inaccessible.

Modifying the Roubaix Load Balancer

We will reconfigure the Roubaix Load Balancer to work with the vRack shared by both sites, so that it can access Prism Central for the Roubaix cluster.

In the Bare Metal Cloud menu, select the Roubaix Load Balancer from the Load Balancer submenu.

Go to Private networks, click on the ... to the right of the existing private network.

04 Modify Load Balancer 01

Click Delete.

04 Modify Load Balancer 02

Click Delete again at the confirmation request.

04 Modify Load Balancer 03

Click Enable to the right of vRack.

04 Modify Load Balancer 04

Select Existing, select the vRack that is common to both sites, and click on Enable.

04 Modify Load Balancer 05

Click Add Private Network.

04 Modify Load Balancer 06

Choose these values:

  • Name (optional): Private network name.
  • VLAN ID: Nutanix management network VLAN, normally 1.
  • Subnet: Private network LAN 192.168.0.0/22.
  • NatIP: Address range used by the Load Balancer 192.168.2.128/27.
  • Name: NutaCluster-all.

The range chosen by NatIp should not be used by other elements of the private network, particularly the range taken by the Gravelines Load Balancer.

Then click Add.

04 Modify Load Balancer 07

A yellow banner appears, indicating that the configuration has not been applied. Click Apply Configuration.

04 Modify Load Balancer 08

Select the Roubaix(RBX) datacentre and click on Apply configuration.

04 Modify Load Balancer 09

The Load Balancer is connected to the vRack shared by both sites, and access to Prism Central for the Roubaix cluster is then available.

04 Modify Load Balancer 10

Go further

Disaster Recovery Plan on Nutanix

Asynchronous or NearSync replication through Prism Element

Advanced replication with Leap

Introduction to vRacks

Join our community of users on https://community.ovh.com/en/.


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