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Quick Tip - How to quickly find the release & build number on VCSA

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I have been spending quite a bit of time in the lab lately (researching, prototyping, breaking things, etc.) and one of the challenges I have is figuring out which environment I am actually logged into. I literally have a dozen VCSA (vCenter Server Appliances) deployed for various testing and I always forget the build and release the system I am currently logged into. A quick way to get this information on your VCSA is to run the following command:

vpxd -v

Note: There is also vpxd.exe for vCenter Server running on Windows which you can also use.

I also noticed in the VCSA 5.1 it used to provide the vCenter Server build and release number when SSH into the host but it looks like this has now changed with the VCSA 5.5 release. I suspect this might be related to some of the security hardening that has been done by VMware on our appliances (which is great) and I assume there maybe an issue by providing the build and version info as part of the SSH banner.

If you wish to re-enable this feature, you can just edit the /etc/ssh/sshd_config and specify the banner to point to /etc/ssh/banner which will includes both the release and build information. In any case, if you are in a pinch and need to quickly figure out the version, you can use the command above.

How to automate NTP configurations on the VCSA using the CLI

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NTP configurations should be a mandatory setting for everyone, regardless of whether we are talking about VMware products or general infrastructure software. It is just as critical as having proper DNS configured and can cause a whole slew of issues if not configured or setup properly. A question that was raised internally a couple of days back was around automating NTP configurations on the VCSA (vCenter Server Appliance) which is normally performed through the VAMI web interface as seen in the screenshot below.

Instead of using the VAMI UI, the user was interested in automating it through the command-line and wondered if this was possible. This is definitely possible among other VAMI operations by leveraging the vpxd_servicecfg utility and there are a couple of options when configuring NTP on a VCSA 5.5 system.

The option that most of you will probably using is to configure a list of NTP servers (comma separated). To do so, you can run the following command (replace the NTP server with your own):

/usr/sbin/vpxd_servicecfg timesync write ntp '172.30.0.100' ''

This command should have a return code of 0, else there maybe an issue connecting to your time source from the VCSA. You can also confirm the operation was successful or query the current configuration by running the following command:

/usr/sbin/vpxd_servicecfg timesync read

If you wish to synchronize your time with the underlying ESXi host through VMware Tools, then you can run the following command:

/usr/sbin/vpxd_servicecfg timesync write tools '' ''

Finally, if you wish to disable time synchronization on the VCSA for whatever reason, you can do so by running this command:

/usr/sbin/vpxd_servicecfg timesync write none '' ''

Note: If the VCSA is joined to an Active Directory domain, then the time synchronization is provided by your Active Directory server and no additional configurations are required.

Once you have configured your NTP servers, you should can also manually force a sync to ensure the current date/time is correct by running the following command:

sntp -P no -r [NTP-SERVER]

How to restart the ESXi management network via command-line?

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A great question that was brought up on Twitter yesterday by Andreas Peetz who asked the following:

Is there a way to restart the mgmt network in ESXi via a cmd line? You can do this from the DCUI, but I want a script! 

There are a variety of reasons why you would want to restart the Management Network on your ESXi host and usually it is related to troubleshooting or configurations such as renewing the DHCP lease on a particular VMkernel interface. For Andreas, it was renewing the DHCP lease and this is actually a use case I have heard from others before. Currently, the only way to restart the Management Network for your ESXi host is using the DCUI (Direct Console User Interface) either through the console using iLO/iDRAC/etc. or remotely over SSH.

Andreas' question is not a new one and I have heard this ask in the past. I have even inquired about it when I was a customer but was told it was not possible and had to use the DCUI. I was not really satisfied with the answer I provided to Andreas, so I decided to do a bit of digging myself and ping some engineers. Apparently this functionality is actually exposed through a legacy command-line utility called esxcfg-vmknic in the ESXi Shell as well as locally/remotely via the ESXCLI network namespace which is used to manage the VMkernel interface (Thanks to Andres for mentioning ESXCLI method).

There are two flags that this command supports which is to enable and disable a VMkernel interface. This is actually what the DCUI is doing when you ask it to restart the Management Network and is very similar to restarting a service on a UNIX/Linux system, it first shutdowns the service and then starts it back up. Given this information, if you wish to restart the Management Network of your ESXi host you can specify the name of the Management Network portgroup and execute the enable operation immediately after performing the disable operation.

To do this from the command-line, you would add a ; (semi-colon) between the two commands so they are executed one after another to ensure your VMkernel interface is enabled after you have disabled it. Here is an example of the command:

esxcli network ip interface set -e false -i vmk0; esxcli network ip interface set -e true -i vmk0