Five minutes in the wizard that decide how smooth the install is
Every Ubuntu Server installation on ESXi starts a few minutes before the installer does - in the create virtual machine wizard. The settings chosen there decide which virtual hardware the installer finds, and two or three of them quietly determine whether the next twenty minutes are smooth or strange. This page walks through the shell settings that matter, and says honestly which ones do not.
The most important choice in the whole wizard is also the easiest to rush past: Guest OS family Linux, version Ubuntu Linux (64-bit). ESXi is not being bureaucratic here. The guest OS type drives the defaults for the virtual hardware - the firmware, the network adapter model, the disk controller - and Ubuntu's defaults are exactly what the installer expects to see.
Pick a generic or wrong guest type and nothing explodes, but you may be handed an older network adapter, legacy BIOS firmware, or a disk controller the installer handles less gracefully. Two dropdowns at the start save a pile of small mysteries later.
On current ESXi versions a new Linux VM defaults to EFI firmware, and for Ubuntu Server that default is correct. Ubuntu has supported EFI booting for many years, and its boot loader is signed, so even Secure Boot can stay enabled - the installer works with it, not against it.
The older BIOS option still exists for compatibility with ancient operating systems. Ubuntu Server is not one of them. Switching to BIOS out of habit buys you nothing and can complicate disk layouts above 2 TB, because legacy booting pairs with the older MBR partition style. Leave EFI alone.
Give the virtual disk 25 GB or more. Ubuntu Server itself fits in far less, but updates, logs and the first application you install all want room, and a full system disk is a miserable first problem to learn on. A virtual disk can be grown later in minutes; it cannot be shrunk without real work, so err on the generous side.
Neither choice changes anything the installer sees - Ubuntu gets the full disk size either way. The difference is purely how the ESXi datastore hands out its real space.
ESXi may offer two adapter types for this VM: E1000e, which emulates a common Intel card, and VMXNET 3, VMware's own paravirtual adapter. For Ubuntu Server choose VMXNET 3. Its driver is built into the Linux kernel, so the installer detects it and configures networking mid-install without any extra packages - you do not need VMware Tools installed first for the network to work.
E1000e also works and is a perfectly good fallback if anything ever looks odd, but it emulates real hardware and carries more overhead. The deeper comparison - guest tools, statistics and management features - belongs to post-install configuration, covered in the companion Ubuntu on ESXi guide.
Under the CD/DVD drive, select Datastore ISO file, browse to the uploaded Ubuntu ISO, and tick Connect and Connect at power on. That last checkbox is the number one reason a brand new VM boots to a message like no operating system found: the ISO file was selected, but the drive was never connected, so the VM had an empty CD drive and an empty hard disk - nothing bootable anywhere.
Start with 2 vCPUs and 2 to 4 GB of RAM. Ubuntu Server is a text-only system with no desktop to feed; it idles happily in very little memory. Reserving enormous hardware for a learning VM does not make it faster - it just starves the other VMs on the host. ESXi lets you change both settings later while the VM is powered off, so start modest and grow when a real workload asks for it.
The complete installation on a live ESXi host - creating the virtual machine and working through the installer screens exactly as they appear.
Watch Full VideoEFI, which is the default. Ubuntu supports EFI and Secure Boot properly, so the modern default needs no changes. BIOS firmware is a legacy option kept for very old operating systems and can limit you to MBR style partitioning.
VMXNET 3 works during installation. Its driver is part of the Linux kernel itself, so the Ubuntu installer detects the adapter and can use DHCP or a static address immediately. VMware Tools (open-vm-tools) is a separate, post-install topic - it is not required for networking.
Thin, unless the datastore space must be guaranteed. Thin provisioning lets the virtual disk file grow only as data is written, which is ideal for labs. The installer sees the full virtual size either way, and the choice can be revisited when the VM becomes a production machine.