VMware Cloud Foundation – Upgrade Precheck Fails for ESXi Config

Whilst working on a few things this week I needed to upgrade my home lab running VMware Cloud Foundation, and was walking through the Upgrade Precheck when I hit a failure for the ESXi Config. During my investigation what I’ve found is that if there is any kind of warning that gets thrown in the Summary of the ESXi host then it will result in the Precheck failing on that host.

This can be very frustrating as some of these warnings are thrown for a good reason and should be assessed and addressed based on your own individual needs, or the warnings can be suppressed for ever. Now I’m not suggesting you should blindly go and suppress all the warnings to unblock the Precheck, nor am I suggesting you should just ignore the Precheck failures and proceed with the VMware Cloud Foundation upgrade regardless.

What I am going to do is share how I approached the issue within the confines of my home lab, where I have full autonomy and only myself to blame if something were to go tragically wrong.

From within the SDDC Manager UI this is what it looks like.

Now let’s take a closer look at the specific warnings I was observing, here we can see that I have a total of three warning messages which are causing my Precheck to fail.

Issue 1 – A security vulnerability which involves a number of remediation steps to be performed – This host is potentially vulnerable to issues described in CVE-2018-3646, please refer to https://kb.vmware.com/s/article/55636 for details and VMware recommendations. KB 55636

Issue 2 – A configuration relating to the location for storing coredumps – No coredump target has been configured. Host core dumps cannot be saved.

Issue 3 – A configuration relating to storing system logs which is a direct result of my setup booting for an SD-Card – System logs on host lax01-m01-esx03.lax.rainpole.io are stored on non-persistent storage.

For context, I simply wanted to walk through the process of performing an upgrade so I needed to basically suppress these warnings temporarily. There are of course actions I could take to resolve them but that would take me much longer and as my setup was essentially a fresh deployment I was less concerned with the side affects.

In order to suppress I wanted to also establish how I could reverse the suppression post deployment essentially putting my system back into the same state before the upgrade, so first I needed to work out what advanced settings of ESXi I needed to modify. These are as follows.

Issue 1

UserVars.SuppressHyperthreadWarning

Issue 2

UserVars.SuppressCoredumpWarning

Issue 3

Syslog.global.logHost

Now I have an understanding of which advanced settings suppressed which warning I could go ahead and make the changes knowing that I could easily reverse them later.

Procedure

Step 1 – Login into the management domain vCenter Server.

Step 2 – Expand vCenter Server > Datacenter > Cluster.

Step 3 – Select the ESXi host, and click the Configure tab.

Step 4 – In the navigator, under System click Advanced System Settings.

Step 5 – Click Edit.

Step 6 – Enter the name into the Filter, update the value using the table below and when all three have been updated click OK.

IssueNameExisting ValueNew Value
1UserVars.SuppressHyperthreadWarning01
2UserVars.SuppressCoredumpWarning01
3Syslog.global.logHostudp://127.0.0.1:514

Step 7 – Repeat Step 3 – Step 6 for each host in the cluster.

Step 8 – Run the Upgrade Precheck again and verify everything has passed.

Step 9 – Go ahead and perform the VMware Cloud Foundation upgrade.

Step 10 – Reverse the Advanced System Settings to the original values.

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