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Description

Provides an overview of how Cloud Server NIC functions work in MCP 2.0

For MCP 1.0 specifics, please see Introduction to Cloud Server NICs in MCP 1.0

Overview

In MCP 2.0, each Cloud Server can have one to ten virtual NICs. Each NIC must be associated with a different VLAN within the Cloud Network Domain. You cannot deploy multiple NICs for a single Cloud Server onto the same VLAN. Each NIC has a unique MAC address so that you can positively identify the NIC within the Guest Operating System. Each NIC must be assigned both a "private" IPv4 address and an IPv6 address from within the IP ranges supported by the VLAN. 

NIC's can be assigned when deploying the server or added/removed/swapped after deployment as described in these articles:

For more details on IP address ranges within a VLAN and restrictions on which IP addresses can be used for a Cloud Server NIC, see Introduction to IP Addressing in MCP 2.0.

Remember the actual IP addressing is done within the Guest Operating System - CloudControl will record the current NIC assignment but cannot guarantee that the Operating System is currently configured to use this IP address.

Cloud NIC Network Adapters and Supported Operating Systems

CloudControl supports five different 'Network Adapters' (also referred to as 'NIC Types') as defined by VMware in their KB article Choosing a network adapter for your virtual machine. These adapters define how the NIC will appear to the Guest Operating System. The five available types are as follows:

  1. e1000 - An emulated version of the Intel 82545EM Gigabit Ethernet NIC. The advantage of this NIC is that it will work even if VMware Tools is not running.
  2. e1000e - This version emulates a newer model of the Intel Gigabit NIC (number 82574) in the virtual hardware. This is known as the 'e1000e' vNIC. e1000e is available only on hardware version 8 (and newer) virtual machines in vSphere 5.
  3. VMXNET3 - VMware's paravirtualized NIC designed for ideal performance. It provides better performance, but does not work unless VMware Tools is running. This means that if VMware Tools stops running, all network connectivity to and from the NIC will be lost until VMware Tools is restored.
  4. VMXNET2/Enhanced - The VMXNET2 adapter is based on the VMXNET adapter, but provides some high performance features commonly used on modern networks, such as jumbo frames and hardware offloads. This virtual network adapter is available only for some Guest Operating Systems on ESXi/ESX 3.5 and later. Because Operating System vendors do not provide built-in drivers for this card, you must install VMware Tools to have a driver for the VMXNET2 network adapter available.
  5. PCNET32/Flexible - The Flexible network adapter identifies itself as a Vlance adapter when a virtual machine boots, but initializes itself and functions as either a Vlance or a VMXNET adapter, depending on which driver initializes it. With VMware Tools installed, the VMXNET driver changes the Vlance adapter to the higher performance VMXNET adapter.

However, the Network Adapters available for a Cloud Server are different depending on the Operating System. The system will only make available whatever adapters are defined by VMware to be 'supported' for the Operating System as defined in the VMware Guest OS Compatibility Guide. Therefore, some adapters may not be available for a given Operating System. For example, Microsoft Windows 2012 and Windows 2012 R2 variants are only supported for the VMXNET3 and e1000e adapters, so the system will only allow these two options for the NICs on this OS. In the case of Operating Systems where the specific version cannot be identified (for example, imports of Ubuntu that are imported as "UBUNTU?/64"), the system will present only options that work for all variants. You can identify the Network Adapters available for a given Operating System by reviewing the listing in the Operating System Dashboard as described in Navigating the Supported Operating Systems Dashboard.

You can choose If a specific network adapter is not specified for a given Cloud Server deployment:

  1. For Guest OS Customization deployments, the system will default to the 'recommended' VMware option for the Operating System
  2. For Non-Guest OS Customization deployments, the system will match the same NIC adapters as the source Image.

After deployment, you can change the Network Adapter for a given NIC on a Cloud Server as described in How to Change the Network Adapter of a NIC on a Cloud Server.

NIC Connection State

In addition to the VLAN association, each Cloud NIC can also be set to a "connected" or "disconnected" state. When the NIC is disconnected (i.e. connected = FALSE), the NIC will not broadcast to the VLAN. It is the equivalent of unplugging the NIC cable from the network switch. This setting can be useful for preventing and/or troubleshooting IP conflicts. With NICs disconnected, the server may still be powered on and accessed via Console (as described in How to Get Virtual Console Access to a Cloud Server) so that you can identify and/or modify the Guest OS IP settings without broadcasting the IP address to the VLAN. This is particularly useful when deploying a server from a Non-Guest OS Customization image where you do not know what IP address is baked into the Image and therefore are unsure whether turning on the new server will cause an IP conflict.

You can toggle the NIC connection setting on an existing Cloud Server from within the Server Dashboard as described in Navigating the Server DashboardIn addition, you can set the NIC connection state when performing the following actions: