VCP 6 Study Note – Advanced Networking Concepts Part2 : Backup restore and recovery management

Backup and restore network configuration

vSphere 5.1 and later enables you to backup and restore the configuration of a vSphere Distributed Switch. It’s possible to restore the virtual network configuration in cases of database or upgrade failure or use backup as template to create a copy to the same vSwitch in new vSphere environment.

Export and Import dVS configuration

Using vCenter >= 5.1 you can export vSphere Distributed Switch and distributed port group configurations to a file. The file preserves valid network configurations, enabling transfer of these configurations to other environments.

Import a stored configuration file to create a new vSphere Distributed Switch or to restore a switch that has been deleted earlier.

Note: It’s possible to use saved configuration file to replicate the switch instance, its host associations, and policies but not replicate the connection of physical NICs to uplink ports or ports on link aggregation groups.

During import procedure it’s possible to Preserve original distributed switch and port group identifiers. This last is useful option for recreating a deleted switch or restore a switch that is failed during upgrade process.

Restore option is useful to reset the configuration of an existing distributed switch to the settings in the configuration file; this process changes the settings on the selected switch back to the settings saved in the configuration file. During restore process it’s possible to restore only dVS or dVS with portgroups.

Export and Import dvpg configuration

Exported dvpg configuration file allows you to preserve valid port group configurations, enabling distribution of these configurations to other deployments. The procedure is quite similar to dVS, the option is available in portgroup element.

Recovery of Management Network

In vSphere >= 5.1 it’s possible to prevent and recover from misconfiguration of the management network by using the rollback and recovery support of the vSphere Distributed Switch and vSphere Standard Switch. This could be done in DCUI too.

Host networking rollbacks occur when an invalid change is made to the networking configuration for the connection with vCenter Server. Rollback are available for:

  • Updating the speed or duplex of a physical NIC
  • Updating DNS and routing settings
  • Updating teaming and failover policies or traffic shaping policies of a standard port group that contains the management VMkernel network adapter
  • Updating the VLAN of a standard port group that contains the management VMkernel network adapter
  • Increasing the MTU of management VMkernel network adapter and its switch to values not supported by the physical infrastructure
  • Changing the IP settings of management VMkernel network adapters
  • Removing the management VMkernel network adapter from a standard or distributed switch
  • Removing a physical NIC of a standard or distributed switch containing the management VMkernel network adapter
  • Migrating the management VMkernel adapter from vSphere standard to distributed switch

vSphere Distributed Switch Rollbacks Distributed switch rollbacks occur when invalid updates are made to distributed switches, distributed port groups, or distributed ports.

  • Changing the MTU of a distributed switch
  • Changing the following settings in the distributed port group of the management VMkernel network adapter
    • Teaming and failover
    • VLAN
    • Traffic shaping
  • Blocking all ports in the distributed port group containing the management VMkernel network adapter
  • Overriding the policies on at the level of the distributed port for the management VMkernel network adapter

It’s possible to disable automatic rollback modifying this key in advanced settings: config.vpxd.network.rollback or modifying vpxd.cfg file:

In vSphere >= 5.1 it’s possible to use the Direct Console User Interface (DCUI) to restore the connection between vCenter Server and a host that accesses the management network through a distributed switch. The option available in DCUI is: Network Restore Options menu –> Restore vDS