Unable to migrate virtual machines across subnets with vMotion after upgrade to vSphere 6.0

Products

• VMware vSphere ESXi

Issue/Introduction

In vSphere 5.x, it is possible to use static routes to allow migration with vMotion across subnets, although this is not officially supported. vSphere 6.0 introduces TCP/IPv4 and multiple netstack instances. vMotion uses TCP/IPv4 to acquire a netstack instance and default gateway to support vMotion across subnets, and this configuration must be used instead of static routing. If you upgrade an environment that was using static routing to vSphere 6.0, you cannot use migration with vMotion across subnets until you update the configuration to use TCP/IPv4.

Resolution

To configure vMotion using TCP/IPv4, you must perform two tasks:

1. Remove any configured static routes from the hosts.
2. Configure the vMotion network stack to use TCP/IPv4.
3. Configure the default gateway if the vMotion traffic is being routed.

Remove Configured Static Routes

To remove configured static routes, from the vCLI, use vicfg-route connection_options --del subnet gateway to remove the static routes from each host.

 

Where:

• connection_options is used to specify a variety of connection options. For more information, see Getting Started with vSphere Command-Line Interfaces
• Use subnet and gateway to specify the subnet and the gateway, respectively. For example, to remove the subnet 192.168.100.0/24 using gateway 192.168.0.1 from the host host.example.com, use vicfg-route --server=host.example.com --del 102.168.100.0/24 192.168.0.1.

Configure the vMotion Network Stack

To configure the vMotion network stack using the vSphere Web Client:

1. Select the host in the vSphere Web Client inventory.
2. On the Manage tab, click Networking.
3. Select Virtual Switches.
4. Click the Add host networking ( ) icon.
5. Select VMkernel Network Adapter and click Next.
6. Select New standard switch and click Next.
7. Select Active Adapters and click the plus icon to add a new adapter.
8. Select a vmnic and click OK.
9. Click Next.
10. From the TCP/IP stack dropdown, select vMotion and click Next.
11. On the IPv4 settings page, configure the IPv4 settings and click Next.
12. Review the settings and click Finish.

A new vMotion TCP/IP stack is created.

Configure The Default Gateway

To ensure that a gateway is configured for the new stack:

1. Select the host in the vSphere Web Client Inventory.
2. On the Manage tab, click Networking.
3. Click TCP/IP configuration.
4. Under TCP/IP Stacks, select vMotion.
5. To edit the stack configuration, click the pencil icon.
6. Click Routing, and enter the gateway address. You must set the gateway when the VMkernel adapter has a static IP address to avoid problems with routing.