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Disabling IPv6 via Command-Line For ESXi 5.1 (Without Automatic Host Reboot)

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IPv6 for the VMkernel interface is now automatically enabled by default for the latest release of ESXi 5.1 and you may have also noticed the additional IP Address in DCUI after the host boots up.

IPv6 support has been around for awhile now and you can enable IPv6 by using the old vSphere C# Client or the new vSphere Web Client. If you enable or disable IPv6, you will need to perform a system reboot for the changes to go into effect. You also have the ability to enable/disable it via the DCUI, which also has been around for awhile as well.

UPDATE: 07/20/15 - For ESXi 6.0, the VMkernel module is name is now tcpip4 instead of tcpip3.

There is one very important thing to note if you do enable/disable IPv6 on the DCUI, after you made your changes and you wish to apply, there is a very important confirmation box that is displayed.

Carefully read the last sentence which is underline in red "In case IPv6 has been enabled or disabled this will restart your host". If you are not careful in reading the confirmation screen, you may hit yes and your host will issue a reboot. If you are going to use the DCUI to enable or disable IPv6, make sure you do not have any running VMs on your host and you should already have your host maintenance mode when making configuration changes to your host.

In addition to the two methods listed above (vSphere Web Client/C# CLient and DCUI) you can easily enable/disable IPv6 using ESXCLI (my preferred method) and restart the ESXi host when you get a chance.

To view whether IPv6 is currently enabled, run the following ESXCLI command (ESXi 5.5 Update 1 the VMkernel module is now called tcpip4):

esxcli system module parameters list -m tcpip3

As you can see from the screenshot above, ipv6 property is set to 1 which means it is enabled.

To disable IPv6, you just need to set the property to 0, run the following ESXCLI command:

esxcli system module parameters set -m tcpip3 -p ipv6=0

We can now reconfirm by re-running our list operation to ensure the changes were made successfully. All that is left is to perform a system reboot, you can either type in "reboot" or use the new ESXCLI 5.1 command:  

esxcli system shutdown reboot -d 60 -r "making IPv6 config changes"

Note: You can run the ESXCLI command locally on the ESXi Shell or you can run the same command remotely by specifying additional connection options & proxy through vCenter Server if you wish. Take a look here for additional connection options for ESXCLI.

Detecting ESXi Remote Syslog Connection Error Using a vCenter Alarm

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I was just cleaning up one of my development labs and found that one of my VCSA (vCenter Server Appliance) which I had configured with vSphere Syslog Collector was no longer capturing logs for several of my ESXi hosts. After looking at some of the ESXi logs, I realized that I had rebooted the VCSA at one point and that caused an interruption in syslog forwarding and then knew immediately that I just needed to reload the syslog configuration via ESXCLI as noted in this VMware KB to restore log forwarding.

After restoring my syslog configurations, I had remembered a neat little trick I learned from one of the VMware TAMs about creating a vCenter Alarm to alert you when an ESXi host is no longer able to reach a remote syslog server. I thought this might be very handy alarm to have in your vCenter Server in case you hit a similar issue or having some connectivity issues with your syslog servers. By default, there is not an event on syslog connectivity but you can create a vCenter Alarm based on an eventId which shows up as "esx.problem.vmsyslogd.remote.failure" in both /var/log/hostd.log as well as /var/log/vobd.log.

Now that we know the eventId, we just need to create a vCenter Alarm which will notify us when it has a connectivity issue with it's configured syslog server.

Step 1 - Create a new alarm, in this example I am calling it "Syslog Connection Error" and you will need to specify the Alarm Type as "Host" and monitor for a specific event.

Step 2 - Next, click on Triggers and we will go ahead and paste in our eventId which is "esx.problem.vmsyslogd.remote.failure"

Step 3 - Lastly, you can configure an Action, if you wish to send an SNMP trap, run a command or send an email notification. In this example, we are just going to generate a regular vCenter Alarm event, so go ahead and just click OK to save the alarm.

To test the alarm, I just disabled the syslog-collector on the VCSA using "service syslog-collector stop" and you should see an alarm generate for any ESXi hosts forwarding it's logs to that particular syslog server.

So now when your ESXi hosts can not reach it's syslog server, you will automatically be notified and can look into the problem immediately. Now having an alarm is great ... but you might be wondering what about the need to reload the syslog configuration on all your ESXi hosts to restore syslog forwarding? This can definitely be a challenge/annoying, especially if the syslog server's connectivity is returned after some amount of time and you have hundreds of hosts.

Well luckily, you no longer have to worry about this, with the latest ESXi 5.0 patch03 that was just released, this problem has been addressed and ESXi syslog daemon will automatically start forwarding logs once connectivity has been restored to the syslog server. It is still definitely recommended that you have more than one syslog server in your environment and that they are properly being monitored. Also, do not forget with ESXi 5.0 you can now configure more than one remote syslog server, for more details take a look at this article here.

Note: After applying the patch, you will no longer be able to generate an alarm based on the eventId for syslog when using UDP. You will see something like "Hostd [290D5B90 verbose 'SoapAdapter'] Responded to service state request" in the hostd.log. The alarm will only be valid if you're using TCP or SSL protocol for syslog which have not been patched with latest p03.

If you are looking for a quick way to reload your syslog configurations, you can easily write a simple for loop to reload your ESXi hosts using the remote ESXCLI:

Here is another example using PowerCLI in-conjunction with ESXCLI:

That's so cool! Running ESXi 5.0 & 5.1 on Apple Mac Mini

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Those of you who follow me on twitter should know that I recently got my hands on an Apple Mac Mini Server (Thanks Randy K.) and are probably thinking I would install Apple OSX on the Mini. Nope! I am actually running vSphere ESXi 5.0 or 5.1 on the Mac Mini!

UPDATE (12/21): Yo no longer need to create a customized ESXi ISO for Apple Mac Mini, the necessary drivers are now included in the new ESXi 5.0 Update 2 and will work out of the box. Please take a look at this article for more details.

UPDATE (01/18): To run ESXi 5.1 on Mac Mini 5,1 or 5,3 please follow the same steps outlined below but for an ESXi 5.1 ISO image. If you are trying to run ESXi 5.0 or 5.1 on the new 2012 Apple Mac Mini 6,2 please refer to this blog post for the instructions.

Disclaimer: This is not officially supported by VMware. Use at your own risk.

Note: I did not have a spare monitor at home and luckily the Mac Mini has a DVI output which I was able to connect to my 46" TV. Nothing like ESXi on the big screen 🙂

Even though this is not officially supported by VMware, it is still a very cool solution and the Mac Mini is great form factor for a vSphere home lab. I also want to mention that this was only possible with the research from the folks over at Paraguin Consulting who initially blogged about the process needed to get ESXi 5 running on a Mac Mini. I would highly recommend you check out their blog post which provides additional details as well as a step by step installation guide including screenshots for each step.

I did not have access to an Apple Super Drive which is what the Paraguin folks used in their installation guide, as they thought formatting a USB key would have taken too long ... and who has a CD burner these days? 😉 There is also an additional step that is needed to get network connectivity which requires the user to manually install a network driver on the ESXi host.

I decided to go down the route of using a USB key to perform the installation and using a spare 1GB USB key, I created a custom ESXi installation that included the network driver which allows for network connectivity during and after the installation.

What you will need:

Step 1 - Extract the offline bundle "tg3-3.120h.v50.2-offline_bundle-547149.zip" from Broadcom zip file

Step 2 - Use Image Builder to add the Broadcom driver and create a custom ESXi 5 ISO (steps taken from this VMware KB article)

# Add the ESXi 5.0 Update 1 Offline Bundle

Add-EsxSoftwareDepot "C:\VMware-ESXi-5.0.0-623860-depot.zip"

# Add the Broadcom Offline VIB

Add-EsxSoftwareDepot "C:\tg3-3.120h.v50.2-offline_bundle-547149.zip"

# Create a new Image Profile (in example, I'm using the full version w/tools)

New-EsxImageProfile -CloneProfile "ESXi-5.0.0-623860-standard" -name "ESXi50u1-Custom"

# Add the broadcom driver to our Image Profile

Add-EsxSoftwarePackage -ImageProfile "ESXi50u1-Custom" -SoftwarePackage "net-tg3"

# Create an ISO from our custom Image Profile

Export-EsxImageProfile -ImageProfile "ESXi50u1-Custom" -ExportToISO -filepath C:\VMware-ESXi-5.0u1-Custom.iso

Step 3 - Plug in a USB key into your system and run UNetbootin which will take the custom ISO we just created and make it bootable on the USB key

Step 4 - Finally, power on your Mac Mini and plug in the USB key. You can either hold the "Alt/Option" key while the system is booting and select the EFI volume OR just plug the USB key and the ESXi installer should automatically start up.

After a few minutes, you should now have ESXi 5 running on your Mac Mini, here is my setup:

Note: If you wish to add a custom kickstart file so it automatically installs and configures the host, take a look at this blog post for the details. If you want the Mac Mini to automatically boot from USB without having to press the "Alt/Option" key after installation, you can set the default boot device by following this article here.

Since you are running ESXi on Apple hardware, you can also create Mac OSX Virtual Machines (10.5 Server and 10.6 Server) and with the latest release of vSphere 5.0 Update 1, OSX 10.7 (Lion) is now officially supported. To install OSX 10.7 as a VM, make sure you follow the instructions here.

Here is a screenshot of running OSX Lion 64bit as a VM running on ESXi 5 running on a Mac Mini 😀

If you are looking to refresh your vSphere home lab, definitely consider looking at the Mac Mini, which can get up to a max of 16GB of memory. Also if you are wondering if other people are doing this, I would recommend you check out Christopher Well's vSamarai blog here which details his experience using the Mac Mini as well as voting for his VMworld CFP which will also include topic about running ESXi on Mac Mini.

I want to thank Randy K. again for lending me the Mac Mini, you rock dude! Hopefully this will not be the last article about the Mac Mini 😉

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