Virtual Network
A Virtual Network is a software defined network that is generally created by a tenant user. By default, the Virtual Networks are isolated from each other, so that the virtual machines created within these networks can not route traffic outside of the network.
Virtual Networks use IP encapsulation techniques, i.e. they use an "underlay network" as the underlying physical transport, but present themselves as an entirely new network to VMs and workloads within the hypervisor cluster.
Types & Setup
You can choose to enable virtual networking for your virtual cluster as part of cluster blueprint configuration.
Virtual Networks in Private Cloud Director support following types:
- VLAN
- VXLAN
- GENEVE
You choose your preferred method for creating virtual networks once per virtualized cluster, as part of cluster blueprint configuration. Then, when you or your tenant users create new virtual networks, this underlying configuration will be used behind the scenes to provision the networks.
VLAN Network
A VLAN virtual network is a virtual network that uses VLAN tagging. When you choose VLAN as your technology for virtual networks as part of cluster blueprint creation, you need to specify the range of VLAN IDs that will get used when new virtual networks get created.
It is important that you select a VLAN range not being used by your current physical network infrastructure.
It is important that you select a VLAN range not being used by your current physical network infrastructure. Not doing this may result in networking connectivity problems with your virtual networks.
VXLAN / GENEVE Network
A VXLAN or GENEVE virtual network uses VXLAN or GENEVE as the encapsulation / overlay technology using IP underlay. When you choose VXLAN or GENEVE as your technology for virtual networks, you need to specify the VXLAN VNID Range or the Geneve Tunnel ID Range that will be used under the hood when new virtual networks get created.
Sharing
By default, a Virtual Network is created in the context of a tenant that will be the default owner of that Network. A Network can be explicitly marked as shared, which will make it accessible to all tenants.
Network Interface
A Network Interface is an interface inside a Virtual Machine. Each Virtual Machine will typically have one or more pairs of (Network Interface and Port) associated with it.
Subnet
A Virtual Network is not really usable without having at least one Subnet as part of it. A Subnet provides a usable IP address range within a layer 2 broadcast domain. Any Virtual Machines belonging to the same subnet can communicate with one another directly without the need for a router.
When you deploy a new Subnet for a Virtual Network using Private Cloud Director UI, the option to deploy a DHCP server for that subnet is selected by default. When selected, a new DHCP server will be deployed for this subnet when it's provisioned. This is the most commonly used scenario for Virtual Network Subnets. But, you may choose to not use a DHCP server for a Subnet if you plan to:
- Assign static IPs to VMs using this Subnet, using
cloud-init - Use an external DHCP server to assign IPs.
Uncheck the box to disable DHCP server for the Subnet in that case.