VMware Cloud on Dell EMC is an on-prem, fully managed SDDC-as-a-Service that is based on the latest VMware Cloud infrastructure software and Dell EMC VxRail hardware. The offering includes everything you need, including the SDDC software stack, physical rack, network equipment, hyperconverged servers, and power distribution.
In the previous post, we offered an overview of the various management networks and explained the purpose of each subnet that must be allocated within the configuration during provisioning. Now we will move to the next phase and discuss how this new infrastructure will connect to your existing data center networks through the included top-of-rack switches – an essential step that enables access to your applications, as well as connectivity to your SDDC management network.
Physical Network Devices
The VMware Cloud on Dell EMC physical rack is outfitted with a pair of top-of-rack switches (ToRs) for highly available networking. Every host in the rack has one 10GbE connection to each switch and are configured with “active/standby” teaming policies.
There is also a dedicated management switch in the rack that is connected to the iDRAC ports on each server and to the applicable management ports for other devices, such as the smart PDUs. These connections offer out-of-band access if VMware engineers must troubleshoot unexpected crashes or other situations that cannot be resolved over the primary management network.
Connectivity to Your Existing Data Center
The VMware Cloud on Dell EMC network architecture can accommodate up to two physical connections from each ToR to your existing network, so you can set up either two or four total uplink connections to your data center. The deployment technician installs either 1GbE SFP or 10GbE SFP+ fiber modules depending on your requirements, offering an aggregate connection of up to 40Gbps if both ports on each switch are using the fastest link speed.
The architecture between these environments is a routed, layer 3 (L3) topology and the load will be balanced through equal-cost multi-path routing (ECMP). Therefore, the network devices on the data center side must be routers – or switches with routing capabilities. For maximum availability, we recommend you make connections to two separate network devices.
To enable IP connectivity across these connections, a point-to-point network is configured for each physical link. These are /30 or /31 networks with your choice of addresses, so coordinate with your network engineer to determine how to best architect this for your environment.
The VMware Cloud on Dell EMC side is configured through the hybrid cloud control plane, as seen in the diagram below:
Routing to the SDDC Management Network
After the connections are established between your data center and the VMware Cloud on Dell EMC rack, your routers must be configured with routes to the networks that need to be reachable. There are essentially two types of networks within the rack that require connectivity: the SDDC management network and NSX-T workload network segments. The latter will be covered in a future post, so please stay tuned.
One reason for a route to be configured to the SDDC management network is to enable direct access to vCenter Server instead of going through the public address. This connectivity will also enable future use cases such as Hybrid Linked Mode, workload migration, and stretched L2 VPN connections.
Work with your network administrator to add route entries to the SDDC management network, which is the /24 subnet specified during provisioning. The applicable IP address on the VMware Cloud on Dell EMC ToRs interface is the next hop.
Equal-cost multi-path (ECMP) routing is enabled by default on the VMware Cloud on Dell EMC ToR switches. If you enable and configure ECMP on your routers, traffic will be load balanced across all of the links.
In addition to the routing configuration, a firewall rule must also be created to allow pings or connections to the vCenter Server on the SDDC management network. Please see the product documentation for an overview.
To verify connectivity to the SDDC management network, either ping or scan the private IP address of vCenter Server from a system somewhere in the data center. This IP address belongs to the SDDC management subnet that you specified during the provisioning flow – the last octet is always 196.
Note that even though you can establish a network connection to the vCenter Server IP address directly from the data center, by default the FQDN is configured to resolve to the secure public address that tunnels into the rack over the VeloCloud SD-WAN connection. This ensures that you can access vCenter Server even before the ToR connections are established.
If direct access is preferred, you can use the hybrid cloud portal to change the FQDN to resolve to the private IP address instead of the public address. Alternatively, to configure just a single client system without affecting other users, add an entry to your /etc/hosts file. This step is necessary because it is not possible to connect to the vSphere Client in a browser by simply using an IP address – a FQDN must be used.
Takeaways
VMware Cloud on Dell EMC is an innovative new offering that provides cloud-like agility for on-prem SDDC infrastructure. VMware handles the lifecycle management so you can focus on deploying the apps that power your business.
In order to consume this new rack of infrastructure, either two or four physical links are connected to your existing data center network to establish a layer 3 path to the networks on the cluster. Consult with your network architect to determine suitable addresses for the point-to-point IP links, as well as to implement the required routing changes in your data center.
For more information on VMware Cloud on Dell EMC, visit the product page or talk to your account team today.
