Building VMware ESXi 4 Tools on CentOS 6

CentOS 6 is not directly supported by version 4 of the VMware ESXi hypervisor, which means that there are no precompiled binaries for the kernel modules required for the VM to talk to the host. This short guide shows you how to manually compile the tools. Note that every time that you upgrade to a newer kernel version, you will have to do this from scratch -- you will have to compile the tools against the new kernel's headers.

Here's the procedure:

From the vSphere client, right click on the machine, open the "Guest" menu and select "Install/Upgrade VMware Tools". This will insert a virtual optical drive in the VM.
Mount the virtual optical drive, not directly on the /mnt directory, since that will be used later by the installer. For example:
```
mkdir /mnt/vmware-tools
mount -o loop /dev/cdrom /mnt/vmware-tools
```
Copy the tools in a writeable location (the mount point of the virtual optical drive will be read-only) and decompress it. For example:
```
cp /mnt/vmware-tools/VMwareTools-4*.tar.gz /root/
cd /root/
tar zxvf VMwareTools-4*.tar.gz
```
Before starting the installation, install a C compiler and the kernel's source code, since the VMware tools installer will need the kernel headers to include while compiling the modules. For example:
```
yum install gcc
yum install kernel-headers
```
Next, start the installation. It will ask a lot of questions, on which you can (most probably) accept the default answers.
```
cd /root/vmware-tools-distrib
./vmware-install.pl
```
Finally, even though you don't normally need to reboot, do it anyway if you can. That way you will verify that the kernel modules are properly loaded after a reboot. You can check that with:
```
[root@centos-6 ~]# lsmod | grep '^vm'
vmmemctl                8642  0 
vmware_balloon          7199  0
```
If everything went fine, you might want to clean up the files you copied and extracted, although keeping them will speed up the reinstallation of the tools in case you upgrade the kernel to a newer version.