ESXi network routes

I honestly don’t know why this is still a problem. Support for routed vmotion traffic was added back at vSphere6. Here we are vSphere7 and still have to set your gateway/routes for the vmotion stack through esxcli.

Either way, here is how it works

vMotion stack

Each tcp/ip stack can only have one gateway, that makes sense. And if you want to keep your management and vMotion traffic separated you need two tcp/ip stacks.

It’s nicely done through vSphere vCenter GUI and there is a KB for it. And you even have the option to override the default gateway and specify the right one for your vMotion stack.

[root@dc1esxcompx-xx:~] esxcli network ip route ipv4 list -N vmotion
Network     Netmask        Gateway  Interface  Source
----------  -------------  -------  ---------  ------
10.1.115.0  255.255.255.0  0.0.0.0  vmk1       MANUAL

But when looking at the routing table from esxcli it is not set. If you know, feel free to give me a kick and enlighten me.

ESXCLI add a static route

So for me to set an actually default route I have to do it as shown below

[root@dc1esxcompx-xx:~] esxcli network ip route ipv4 add -g 10.1.115.1 -n 0.0.0.0/0 -N vmotion

[root@dc1esxcompx-xx:~] esxcli network ip route ipv4 list -N vmotion
Network     Netmask        Gateway     Interface  Source
----------  -------------  ----------  ---------  ------
default     0.0.0.0        10.1.115.1  vmk1       MANUAL
10.1.115.0  255.255.255.0  0.0.0.0     vmk1       MANUAL

PowerCLI

Need to do it on a cluster with multiple hosts? No problem LucD from VMware community got you covered. I only did a little customization and it works for my needs.

connect-viserver -Server 

$stackName = 'vmotion'
$ipGateway = '10.1.115.1'
$ipDevice = 'vmk3'
$cluster = "computexx"
$vmhosts = get-cluster $cluster | get-vmhost

foreach($vmhost in $vmhosts)
{
$esx = Get-VMHost -Name $vmhost
$netSys = Get-View -Id $esx.ExtensionData.ConfigManager.NetworkSystem
$stack = $esx.ExtensionData.Config.Network.NetStackInstance | where{$_.Key -eq 'vmotion'}
$config = New-Object VMware.Vim.HostNetworkConfig
$spec = New-Object VMware.Vim.HostNetworkConfigNetStackSpec
$spec.Operation = [VMware.Vim.ConfigSpecOperation]::edit
$spec.NetStackInstance = $stack
$spec.NetStackInstance.ipRouteConfig.defaultGateway = $ipGateway
$spec.NetStackInstance.ipRouteConfig.gatewayDevice = $ipDevice
$config.NetStackSpec += $spec
$netsys.UpdateNetworkConfig($config,[VMware.Vim.HostConfigChangeMode]::modify)
}

Conclusion

Manipulating the vmotion stack route table with either esxcli or PowerCLI is working great.

Need to know more? there are plenty of good bloggers and KBs out here.

Jesper Ramsgaard