This post provides an overview of cross-vCenter NSX and walks through the configuration steps. Cross-vCenter NSX allows central management of network virtualization and security policies across multiple vCenter Server systems. Cross vCenter NSX introduces universal objects; such as universal logical switches, universal logical routers, and universal distributed firewall rules. Universal objects are able to span multiple sites or vCenter Server instances, enhancing workload mobility by allowing cross vCenter and long distance vMotion for virtual machines, whilst keeping the same network settings and firewall rules. This improves DR capabilities, overcomes scale limits of vCenter Server, and gives administrators more control over resource pooling and the separation of environments.
Cross vCenter-NSX was introduced in NSX v6.2 and requires vSphere v6.0 or later. As normal NSX Manager is deployed with vCenter server in a 1:1 pairing. In a single site NSX deployment the NSX Manager is given the standalone role by default. When configuring cross-vCenter NSX one NSX Manager is assigned the primary role, and up to seven other NSX Managers are assigned the secondary role. NSX Managers configured for cross-vCenter NSX must all be running the same version. The primary NSX Manager is responsible for deploying the Universal Controller Cluster; forming the control plane across the NSX Managers. The Universal Controller Cluster runs in the site of the primary NSX Manager. Universal objects are created on the primary NSX Manager and automatically synchronized across the multi-site NSX environment.
Configuring Cross-vCenter NSX
The steps below assume you have already deployed and registered the NSX Managers, and have a good understanding of NSX. This post is intended as add on to the NSX Install Guide to provide an outline of the additional or different steps required for a cross-vCenter NSX install, further resources are listed at the bottom of the page. If you are using vCenter enhanced linked mode then multiple NSX Manager instances are displayed within the same interface, or single pane of glass, when managing the Network & Security section of the vSphere web client. Enhanced linked mode is not a requirement for cross-vCenter NSX however, and vCenter Server systems not in enhanced linked mode can still be configured for cross-vCenter NSX.
From the Networking & Security page of the vSphere web client select Installation, highlight the NSX Manager in the primary site, from the Actions menu select Assign Primary Role.
The secondary NSX Manager(s) synchronize with the primary using the Universal Synchronization Service. These sites do not run any NSX Controllers, although they can be redeployed easily in the event of a primary site outage. Before assigning the secondary role you should ensure there are no existing NSX Controllers deployed in the associated vCenter. If you have already assigned a segment ID pool to the NSX Managers then ensure the segment ID pools do not overlap. Select the primary NSX Manager and from the Actions menu click Add Secondary NSX Manager. Enter the secondary NSX Manager information and admin password.
Review the table of NSX Managers, the roles have now changed accordingly.
The universal controller cluster is formed by individually deploying the NSX controllers from the primary NSX Manager, the method of deploying the controllers is the same (see NSX Install Guide Part 1 – Mgmt and Control Planes for further assistance). Once the controllers are deployed you will notice placeholder controllers listed against the secondary NSX Manager, these are not connected or deployed. In the event of a site failure the configuration is synchronized between NSX Managers so you can simply re-deploy the controllers in the DR site. To see the failover process review this blog post. VMware recommend deploying 3 controllers on different hosts with anti-affinity rules.
The next part of the install process is to follow the host preparation and VXLAN configuration steps as normal (see NSX Install Guide Part 2 – Data Plane for further assistance). Create the segment ID pools for each NSX Manager, making sure they do not overlap. On the primary NSX Manager you will also assign a universal segment ID pool.
In order for us to deploy universal logical switches we need to create a universal transport zone. A universal transport zone determines which hosts a universal logical switch can reach, spanning multiple vCenters. From the Logical Network Preparation tab open Transport Zones, ensure the primary NSX Manager is selected and click the plus symbol. Select Mark this object for Universal Synchronization, and enter the configuration for the universal transport zone. All universal objects must be created on the primary NSX Manager, change the NSX Manager to the secondary site and you will see the universal transport zone has synchronized there also.
Next we will create a universal logical switch for the transit network. Local objects such as logical switches, logical routers, and Edge Services Gateways can still be deployed from each NSX Manager, although by design they are only local to the vCenter linked to that specific NSX Manager, and cannot be deployed or edited elsewhere. From the left hand navigation pane in Networking & Security select Logical Switches, ensure the primary NSX Manager is selected and click the plus symbol. Enter a name for the transit network and select the universal transport zone we created earlier.
At this stage you can also deploy another universal logical switch, connecting a couple of test VMs on a private subnet, and have them ping one another to confirm connectivity. Now that we have a transit network and test universal logical switches connected to our universal transport zone we can go ahead and create a universal DLR. In this particular environment we have already deployed an ESG in each site. For further assistance with deploying an ESG and DLR see NSX Install Guide Part 3 – Edge and DLR.
From the Networking & Security page click NSX Edges, ensure the primary NSX Manager is selected and click the plus symbol. The control VM for the DLR is deployed to the primary site, again the configuration is synchronized and this can be re-deployed to the DR site in the event of a primary site outage. Select Universal Logical Router and follow the wizard as normal, if local egress is required then check the appropriate box. Sites configured in a cross-vCenter NSX environment can use the same physical routers for egress traffic, or have the local egress feature enabled within a universal logical router. The local egress feature allows routes to be customized at host, cluster, or router level.
From the NSX Edges page double click the new universal DLR, select Manage, Settings, Interfaces and click the add button. In order for traffic to route from the universal DLR to the ESG(s) we must add an uplink interface connecting them to the universal transit network. Change the logical router interface to Uplink, in the Connected To field select the transit network universal logical switch we created earlier. Configure the IP and MTU settings of the interface per your own environment.
You can also add Internal interfaces here corresponding with universal logical switches for virtual machine subnets. Before these subnets can route out follow the same process to add an Internal interface to the ESG(s) connecting them to the same transit network.
A virtual machine connected to the test universal logical switch can now vMotion between sites keeping the same IP addressing, providing L2 over L3 capability. As well as remaining on the same logical network a virtual machine can also be migrated across sites without any additional firewall rules, this is achieved with the use of universal firewall rules. Universal firewall rules require a dedicated section creating under the Firewall section of Networking & Security, you must select Mark this section for Universal Synchronization. For assistance with creating universal firewall rules see here.
Additional Resources
To plan a cross-vCenter NSX installation review the VMware Cross-vCenter NSX Design Guide, Cross-vCenter NSX Topologies Guide, and the VMware Cross-vCenter Installation Guide. For more information on cross-vCenter NSX design see the following blog posts:
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