Upgraded a Supermicro CSE-836 from 3 pin fans to 4 pin PWM fans. Here is the before and after matrix of part numbers:

Note: the above matrix was for replacements in kind. The latest CSE-836 has these fans:
Middle: FAN-0126L4 (Qty 3)
Rear: FAN-0125L4 (Qty 2)

Note: an alternative 4 pin hot swap cable is CBL-0216L

When trying to update/upgrade ESXi 6.7.0 Update 3 (via software profile update command) you may run into the following error below. This was a host running specifically Update 3 build 15018017 trying to update to build 15160138.

[InstallationError]
[Errno 28] No space left on device
vibs = VMware_locker_tools-light_11.0.1.14773994-15160134
Please refer to the log file for more details.

When attempting to update to build 16075168, the failure is related to: vibs = VMware_locker_tools-light_11.0.5.15389592-15999342, you can substitute this version into the commands below, keeping everything else the same.

First make sure you have Swap enabled on a datastore.  In vSphere Web Access, navigate to Host->Manage->Swap and choose a datastore.

Then manually install the VMware_locker_tools package by following these steps via SSH on the host:

cd /tmp

wget http://hostupdate.vmware.com/software/VUM/PRODUCTION/main/esx/vmw/vib20/tools-light/VMware_locker_tools-light_11.0.1.14773994-15160134.vib

esxcli software vib install -f -v /tmp/VMware_locker_tools-light_11.0.1.14773994-15160134.vib

Once you receive verification that the Operation finished successfully, try the profile update command again to patch ESXi.

When trying to update a CentOS 7 system after an extended amount of time, I ran into this error:

Downloading packages:
warning: /var/cache/yum/x86_64/7/ius/packages/yum-plugin-replace-0.2.7-1.ius.el7.noarch.rpm: Header V4 RSA/SHA256 Signature, key ID 4b274df2: NOKEY
Retrieving key from file:///etc/pki/rpm-gpg/IUS-COMMUNITY-GPG-KEY

The GPG keys listed for the “IUS Community Packages for Enterprise Linux 7 – x86_64” repository are already installed but they are not correct for this package.
Check that the correct key URLs are configured for this repository.

Failing package is: yum-plugin-replace-0.2.7-1.ius.el7.noarch
GPG Keys are configured as: file:///etc/pki/rpm-gpg/IUS-COMMUNITY-GPG-KEY

In this example I was trying to install the package yum-plugin-replace, but a similar error can occur with other packages you may have installed as well.  The solution was to reinstall the IUS repository (https://ius.io/setup)

sudo yum install \
https://repo.ius.io/ius-release-el7.rpm \
https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

Once complete retry the update

sudo yum update

At which point you may run into the below message.  The fingerprint should match https://ius.io/keys, then type Y to finish.

Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-IUS-7
Importing GPG key 0x4B274DF2:
Userid : “IUS (7) <[email protected]>”
Fingerprint: c958 7a09 a11f d706 4f0c a0f4 e558 0725 4b27 4df2
Package : ius-release-2-1.el7.ius.noarch (installed)
From : /etc/pki/rpm-gpg/RPM-GPG-KEY-IUS-7
Is this ok [y/N]: