Create an (IP alias / secondary administration network) on VMware ESXi

For some reasons, I need to create a secondary administration network on my ESXi servers. As I don’t need the routing stuff, I thought I’d create IP aliases as I would do with any UNIX server. But on the ESXi, it is just no possible, AFAIK.

The solution is to create another VMkernel port, used for management, on the ESXi. As I don’t want to use any extra hardware, I’ll create the portgroup in the existing vSwitch. Here’s how.

For the fun, and because I only had access to the ESXi shell by that time, I created the secondary VMkernel port using the CLI. Connect to the ESXi via SSH and have a look at the actual configuration:

# esxcfg-vswitch -l Switch Name Num Ports Used Ports Configured Ports MTU Uplinks vSwitch0 128 6 128 1500 vmnic0,vmnic1 PortGroup Name VLAN ID Used Ports Uplinks VM Network 0 2 vmnic0,vmnic1 Management Network 0 1 vmnic0,vmnic1 # esxcfg-vmknic -l Interface Port Group/DVPort IP Family IP Address Netmask Broadcast MAC Address MTU TSO MSS Enabled Type vmk0 Management Network IPv4 192.168.0.62 255.255.255.0 192.168.0.255 00:0c:29:1d:80:05 1500 65535 true STATIC

Let’s create the new VMkernel port group in the current vSwitch:

# esxcfg-vswitch -A "VPN Network" vSwitch0 # esxcfg-vswitch -l Switch Name Num Ports Used Ports Configured Ports MTU Uplinks vSwitch0 128 6 128 1500 vmnic0,vmnic1 PortGroup Name VLAN ID Used Ports Uplinks VPN Network 0 0 vmnic0,vmnic1 VM Network 0 2 vmnic0,vmnic1 Management Network 0 1 vmnic0,vmnic1

Then, just assign the VMkernel IP to the new portgroup:

# esxcfg-vmknic -a -i 10.15.5.62 -n 255.255.255.0 "VPN Network" # esxcfg-vmknic -l Interface Port Group/DVPort IP Family IP Address Netmask Broadcast MAC Address MTU TSO MSS Enabled Type vmk0 Management Network IPv4 192.168.0.62 255.255.255.0 192.168.0.255 00:0c:29:1d:80:05 1500 65535 true STATIC vmk1 VPN Network IPv4 10.15.5.62 255.255.255.0 10.15.5.255 00:50:56:7f:8e:58 1500 65535 true STATIC

The ESXi can now be managed either via vmk0 and/or vmk1.
Using the vSphere Client, here’s what we see:

Beware that “(…) Only 1 VMkernel port is allowed per subnet on a vSwitch in ESX/ESXi.”
One has tested setting DHCP on the secondary interface and it just wrapped the ESXi. In such case, either restore default IP settings from the console or use the following command, from console shell:

# esxcfg-vmknic -d -p "VPN Network"

Source: Configuring a VMkernel port and enable vMotion via command line

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