vSphere Networks

[rickd33]

Ive been looking at the different vSphere networks but they raise some questions:

• VMMgmt - With respect to VMware management components this is internal communication between the VM devices. There I suspect a majority if not most of the VMware components would sit of this network. Is my understanding correct?
• VCHA - This page VMware Knowledge Base mentions you should use a dedicated network for the VCHA. But why? Why can we not place it on the VMMGMT network?
• VM External - What VMs would be placed on this network? In terms of VC this normally has a single interface. Or in typical deployments is a 2nd interface added so that 1 x VMGMT and 1 x VM External.

Thanks

[daphnissov · Accepted solution]

• VMMgmt - With respect to VMware management components this is internal communication between the VM devices. There I suspect a majority if not most of the VMware components would sit of this network. Is my understanding correct?

No, Management (not VM Management) is the interface required by ESXi so it can be managed remotely, either by and end user directly, programmatically, or via vCenter Server. This has no relation to virtual machines running on the host.

• VCHA - This page VMware Knowledge Base mentions you should use a dedicated network for the VCHA. But why? Why can we not place it on the VMMGMT network?

vCHA must have a separate network for heartbeat communication. Most distributed systems require this (see WFC and others) in order to determine when failure occurs. You must use a dedicated network. vCHA is optional.

• VM External - What VMs would be placed on this network? In terms of VC this normally has a single interface. Or in typical deployments is a 2nd interface added so that 1 x VMGMT and 1 x VM External.

This would just be a VM network. Any VM can use this to communicate.

[rickd33]

Hi,

Thanks, but I think there are some points that are slightly confused.

VMMGMT is communication between VMs. The Management network is for VMK traffic.

You say VCHA must have a dedicated network, but why? From what I can see there is no real reason not to collapse this into VMMgmt.

Appreciate your comments, and response : )

[IRIX201110141]

VCHA, like all other cluster stuff as Windows Failover, Exchange DAG and so on use a private network for Heartbeat, syncronizing.  So no other network device can broadcast into this or the danger of double IP addresses. This is why you have to separate it.

Regards,

Joerg

[rickd33]

Thanks. Is there any VMware reference that states this. As a broadcast would not cause an issue only if there was a duplicate IP configured.

[daphnissov]

Thanks. Is there any VMware reference that states this. As a broadcast would not cause an issue only if there was a duplicate IP configured.

vSphere Availability 6.5 document, PDF p. 59, sub-heading vCenter HA Hardware and Software Requirements, table 4-2.

And your earlier question when you say

VMMGMT is communication between VMs. The Management network is for VMK traffic.

You keep saying "VMMGMT" but there is nothing in the vSphere landscape with this name to my knowledge. If you're seeing this some place, please provide the source.

There is no such thing as a network providing VM-to-VM communication, only general VM communication. This is called a Virtual Machine port group. It's the same technology which allows VMs to communicate with one another as well as the outside world.

[rickd33]

In terms of VMMgmt this is taken from NFV 2.0.1 (page 31) - https://docs.vmware.com/en/VMware-vCloud-NFV/2.0/vmware-vcloud-nfv-reference-architecture-20.pdf

[daphnissov]

That's referring to a separate virtual machine network on which management components (vRealize Suite VMs) are placed to segregate traffic. It's just another standard virtual machine port group and nothing special.