vSphere Distributed switch span across multiple VMware cluster.

[SamArun]

Hi All,

I would like to explain a scenario and would need endorsement which goes with the best practise of vSphere Distributed Switch Networking with vSphere 6.5.

Also i have attached the drawing which explains the network.

Scenario:

In a single DataCentre there are multiple clusters which host specific workloads according to the client’s environment.

Clusters1 -> Management Cluster -> workload related to vSphere Infra (vcsa, psc, srm, etc.)

Cluster2 -> DMZ Cluster -> workload related to DMZ zone

Cluster3 -> SAP Cluster -> workload related to SAP applications

Networking:

ESX Management, vMotion, FT network share the same VLAN for all three clusters.

VM Data Network for each cluster are different.

Question is: -

Can I have 1xVDS spanned across 3 clusters, though the VDS is an DataCenter object within vCenter?

The MGMT, vMotion & FT network share common vlan across these clusters. Can we have single dvPorgGroup for above three networks spanned across these clusters?

[vijayrana968]

Any specific reason for single VDS ! For Isolation and smooth management I would prefer single VDS per cluster unless I have very small setup. You have SAP cluster and you won't vmotion SAP VMs to management cluster if you are using specific hardware for SAP and Management VMs. However, below are some pre-requisites you must prepare before single VDS for all 3 cluster.

> All 3 Clusters must have an access to the same datastore for successful VMotion.

> vMotion network must be stretched between clusters.

> Processors must be from the same vendor (Inter or AMD) and family (model) on both clusters or both clusters have common EVC baseline applied.

> Virtual Machine hardware version is supported by hypervisor – very useful during migration to new hardware or new version of vSphere platform.

> For VDS, make sure dvportgroup is span across both clusters

[srodenburg]

"Can I have 1xVDS spanned across 3 clusters"

Yes.

It is common practice if there are multiple clusters that have identical network requirements.

"The MGMT, vMotion & FT network share common vlan across these clusters. Can we have single dvPorgGroup for above three networks spanned across these clusters?"

No.

You cannot have some portgroups in some clusters and some others in all the clusters.

ESXi servers are added to a dvSwitch and it's an all or nothing approach. All ESXi severs in all clusters will get the same portgroups. So what you want, i'll call it "selective portgroup membership", cannot be done.

What you need to do is create separate dvSwitches for each clusters. Have them have their unique, cluster-specific portgroups but also create portgoups with identical names and VLAN ID's in all three dvSwitches. That way, the portgroups that you want to share are optically available in all clusters. This way it's easy for the admins and Hosts and VM's can communicate (because the VLAN ID's are the same), but technically they are different dvSwitches (one per cluster).