Ubuntu Virtualization on ESXi - Setup, Configure, Troubleshoot

Before You Start — What the Host Needs

Three things must be true before the creation wizard opens. First, ESXi itself is installed on the host and you can reach its web client — the host machine is now a hypervisor, not a normal PC, so everything happens through that web interface. Second, the host BIOS has CPU virtualization (Intel VT-x or AMD-V) switched on; without it, 64-bit guests will refuse to run. Third, you need space and an image: a datastore with free space (a first Ubuntu VM is comfortable in 40 GB) and the Ubuntu ISO uploaded to that datastore through the Datastore browser. Pick a current LTS release so the VM gets years of updates.

Create the Virtual Machine

In the ESXi web client, choose Create / Register VM and then Create a new virtual machine. The choices that matter: give the VM a name that says the job (like ubuntu-files or ubuntu-test, not "VM 3"); leave Compatibility at the host default — a higher virtual hardware version unlocks newer virtual devices, and lowering it only matters when a VM must move to an older host; set Guest OS family: Linux and version: Ubuntu Linux (64-bit) — this is not decoration, it presets sensible virtual hardware for Ubuntu; and pick the datastore with room on it. On the customize screen, set CPU, memory, disk, network and firmware as the next step explains.

The Four Settings That Decide Everything

Firmware: EFI. Modern Ubuntu expects EFI, EFI is what enables Secure Boot, and it is the ESXi default for new Linux VMs. Legacy BIOS still works for Ubuntu, but treat the choice as permanent — an installed OS expects the firmware it was installed under.

Disk: thin provisioned. A thin disk grows as Ubuntu writes data, so a 40 GB disk might use 12 GB on day one. Thick provisioning reserves the full size up front — safer for critical servers, wasteful for labs.

Network adapter: VMXNET3. It is VMware's own virtual network card, built for virtual machines, and Ubuntu carries its driver in the kernel. The emulated E1000E also works and is the fallback for odd cases.

Size: start small. 2 vCPU and 4 GB RAM run Ubuntu Server happily and Desktop acceptably. You can add more later in a minute; an oversized VM mostly wastes the host.

Install Ubuntu

Attach the ISO to the VM's CD/DVD drive, tick Connect at power on, power the VM on and open the console. Ubuntu's installer behaves exactly as it does on a physical machine. Choose Server or Desktop — Server for services and learning the terminal, Desktop only if you truly need the graphical environment. Let the installer use the whole virtual disk; it is a file on the datastore, nothing physical is being erased. Create your user, set a strong password, and on Server installs tick the OpenSSH server option so you can log in remotely afterwards. When the install finishes, reboot — and disconnect the ISO from the CD/DVD drive.

First Boot Jobs — open-vm-tools and Updates

A fresh Ubuntu VM works, but ESXi is half blind to it: the host summary shows no IP address, and "shut down" from the host is a hard power cut, not a clean shutdown. The fix is one package from Ubuntu's own repository — VMware's recommended route for Ubuntu. Do not use the old ISO-based VMware Tools installer in the ESXi menu; for Ubuntu, open-vm-tools is the supported path and it is kept current by Ubuntu's normal update system.

sudo apt update
sudo apt install open-vm-tools

On Desktop installs, also add the desktop package: sudo apt install open-vm-tools-desktop — it is what makes console resolution, copy-paste and drag-and-drop behave. Then confirm the service is running and finish with the normal updates:

sudo systemctl status open-vm-tools
sudo apt upgrade

The status should show the service active and running. This one package is what gives the host the guest IP address and hostname, enables graceful shutdown from ESXi, and decides how time sync and quiesced snapshots behave.

Verify the VM from the Host

Refresh the VM's summary page in the ESXi web client: the guest IP address and hostname now appear, which proves open-vm-tools is talking to the host. Test a graceful shutdown from the host — Ubuntu should power off cleanly instead of being cut. From here, do daily work over SSH rather than living inside the console; the console is for installs and emergencies, SSH is faster and gives you a proper terminal.

Troubleshooting — Match the Symptom to the Fix

When an Ubuntu VM misbehaves, the symptom usually names its own cause. Work this map in order:

VM will not boot, or boots the installer again — the ISO is still connected, the boot order is wrong, or the firmware was changed after install. No network — check the adapter type and port group first, then inside Ubuntu check whether the network configuration still points at an old MAC address. Host shows no IP and shutdown is a power cut — open-vm-tools is missing or stopped; reinstall it as in Step 5. Console tiny, laggy or clipboard dead — a console/display setting issue; for daily work, use SSH instead. Clock drifting — fix time sync with NTP inside Ubuntu. Everything slow — the host is over-committed; compare total vCPU and RAM given to VMs against the physical machine before blaming Ubuntu.

Two quick checks inside Ubuntu cover most of the detective work — your network addresses and interfaces, and the clock state:

ip a
timedatectl

Most "ESXi problems" turn out to be one setting, one package, or one honest hardware limit.