I have often got to interact with customers who had an issue getting the NSX VIB installed on their ESXi host. Most of the time, it is a tedious configuration issue or a step that they have forgotten. I have hit a similar issue today in my lab with me missing a simple step and wanted to share the error and the fix with others just in a hope it helps others recover from the same error quicker.

I was getting the following error every time I tried to install the NSX 6.4.5 VIB on my ESX 6.7U2 host, and similar error as well when I try to run the resolve button. The error stated “Unable to access agent VIB module at https://192.168.1.211/bin/vdn/vibs-6.4.5/6.7-13168956/vxlan.zip (_NSX_87_VTRES01_VMware Network Fabric). A screen shot of the errir is below.

There was a more detailed error on my NSX screen, which unfortunately I seem to have lost the screenshot for, but it stated something like below:

vtesxi01.vt.com: Unable to access agent offline bundle at https://192.168.1.211/bin/vdn/vibs-6.4.5/6.7-13168956/vxlan.zip.
Cause : <esxupdate-response>
<version>1.50</version>
<error errorClass=”MetadataDownloadError”>
<errorCode>4</errorCode>
<errorDesc>Failed to download metadata.</errorDesc>
<url>https://vtvc01.vt.com:443/eam/vib?id=ecf4a884-c9f5-406c-b57e-75a6613a3651</url>
<localfile>None</localfile>
<msg>(‘https://vtvc01.vt.com:443/eam/vib?id=ecf4a884-c9f5-406c-b57e-75a6613a3651’, ‘/tmp/tmpjnw369p9’, ‘[Errno 14] curl#6 – “Couldn\’t resolve host \’vtvc01.vt.com\’”‘)</msg>
</error>
</esxupdate-response>

As I have seen this one before, I was immediately able to spot that the fix is more than likely I have forgotten to setup Forward or Reverse DNS record or configuration for one of my setup component being ESXi, vCenter or NSX. As it is most of the time the case the component was forgotten is the DNS Server Configuration on my ESXi host, which I have fixed as follow:

1- In vCenter, Click on the ESXi host you are trying to check/fix the DNS setting on.

2- Hit the configure tab, then under Networking tab on the left side, choose TCP/IP Configuration

3- From under Systems Stack choose Default, then hit edit

4- Insert your DNS information, as show in the sample screen below for my environment

5- Hit OK

Now, all you have left to do is go back to the NSX Host Preparation tab and Click Resolve on the host you have just updated the DNS configuration for. This should fix the issue and your host should be prepared successfully and it should look something like the below screenshot.

I hope this will save you from trying to install the NSX VIB manually endless number of times, which I have seen may admins before struggle with. As this issue usually does not go away with manual install of the VIB,  but as you can see you can easily enough fix the root cause of it.