May 27th, 2009 | 
Author: Frequently customers have specific NICs (like onboard NICs) that they’d like assigned to the COS, leaving the other NICs for VM traffic. This is difficult, however, when using our automated kickstart deployment scripts as there is no way to explicitly define the vmnic assigned to the COS. And to make matters worse, the VMkernel is not yet available to us during the %post section of the kickstart script, which makes COS networking configuration difficult! Recently I had a customer who was getting frustrated because …
- They would “rack and stack” a physical server and wire up their NICs accordingly (i.e. onboard NICs on the management VLAN, remaining NICs on production VLANs)
- PXE boot the server
- When kickstart completed, they’d lose connection to the COS.
This happens because during installation, ESX just assigns vmnic0 to the lowest PCI number, and then assigns vmnic0 to the COS. And this is often not the NIC the admin wants used for their COS. Of course, they could go back after the fact and reconfigure the COS networking, but this kind of defeats the purpose of a completely hands-free, automated deployment.
Here is one possible solution to the problem. Below is a script I wrote to append to the %post section of a kickstart file. Obviously, you’ll need to make modifications for your environment.
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## This script should be appended to the %post section of an ESX kickstart file. %post
cat > /tmp/esx_post_install.sh << EOF ## If your kickstart file has vmportgroup=1, you *might* want to uncomment the /usr/sbin/esxcfg-vswitch -A “VMkernel” vSwitch0 ## You’ll need to find which physical NICs you want assigned to your COS. From
/usr/sbin/esxcfg-nics -l | awk ‘\$0 ~ /search term/ {print \$1}’ | xargs –n 1 /usr/sbin/esxcfg-vswitch vSwitch0 –L ## Note: if you want to test the line above from the command-line, you’ll need ## Replace the x.x.x.x after -i with the IP address and after -n with the ## Replace the x.x.x.x after -i with the IP address and after -n with the subnet ## Replace x.x.x.x with the default gateway for the COS in both of the next two lines. mv /etc/rc.d/rc.local.save /etc/rc.d/rc.local
chmod +x /tmp/esx_post_install.sh cat >> /etc/rc.d/rc.local << EOF |
As an example, in my environment I have server with 4 NICs and by default, ESX assigns vmnic0, which is mapped to PCI 02:00.00, to the service console. However, what is actually physically wired to my management network is vmnic3, which is mapped to PCI 02:03.00. In the script above, I simply searched for the number 3 (i.e. replaced search term with 3) and now my scripted ESX installation works properly.
Below is the configuration of my server before I redeployed with kickstart. The line in red is the NIC I want assigned to the COS. The lines in black are what ESX assigns the COS by default.
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BEFORE (without %post section)
PortGroup Name VLAN ID Used Ports Uplinks |
Now, here is the same output after I redeployed the server with my modifications to the %post section of the kickstart file. The scripted deployment of ESX now properly assigns vmnic3 to my service console.
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AFTER (with %post section)
[root@vesx7 root]# esxcfg-nics -l
[root@vesx7 root]# esxcfg-vswitch -l
PortGroup Name VLAN ID Used Ports Uplinks |
I hope this was helpful. Let me know if you have any questions.
Well, I’d better sign off and start packing because I leave for Omaha, NE in a few hours.
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http://www.virtualpro.co.uk Virtualpro
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http://www.virtualpro.co.uk Virtualpro
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http://blog.scottlowe.org/2009/06/25/virtualization-short-take-27/ Virtualization Short Take #27 – blog.scottlowe.org – The weblog of an IT pro specializing in virtualization, storage, and servers
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http://www.linkedin.com/in/asmolenko Andrey Smolenko
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John Warburton