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Key takeaways
- ESXi is a type 1 (bare-metal) hypervisor: it installs directly on the hardware, with no host OS underneath. Its small footprint keeps both the attack surface and the patching workload down.
- Hardware compatibility must be checked before installing, in the VMware compatibility guide. You also need an 8 GB minimum USB stick prepared with a tool such as Rufus, and access to the server console (iDRAC, iLO or IPMI) since the installation is interactive.
- The installer is driven from the keyboard:
Enterto start,F11to accept the EULA, pick the target disk, then set therootpassword. It is the only account available after installation, so keep it safe. - The DCUI console (the yellow and grey screen) opens with
F2: that is where you set the static IP address, netmask, gateway and DNS servers through "Configure Management Network". Day-to-day administration then happens in the Host Client athttps://<esxi-ip>/. - The free licence does not allow attaching the host to a vCenter Server. vMotion, HA, DRS and the centralized backup APIs all require a paid licence, starting with the vSphere Essentials Kit.
What is VMware ESXi?
VMware ESXi is a "type 1" (or "bare-metal") hypervisor, which means it installs directly on a server's physical hardware, without requiring an underlying operating system. It is at the heart of the VMware vSphere virtualization suite and is renowned for its robustness, performance, and small footprint.
VMware ESXi is a "type 1" (or "bare-metal") hypervisor, which means it installs directly on a server's physical hardware, without requiring an underlying operating system. It is at the heart of the VMware vSphere virtualization suite and is renowned for its robustness, performance, and small footprint.
Why Use ESXi?
- Performance: Direct access to the hardware for high-performance virtualization.
- Stability: A reduced footprint means fewer components to update and a smaller attack surface.
- Rich ecosystem: Integrates seamlessly with advanced management tools such as vCenter Server, vSAN, and NSX.
- High Availability: Supports features such as vMotion (live migration), High Availability (HA), and Fault Tolerance (FT) with vCenter.
Prerequisites
- Compatible hardware: Check your server's compatibility on the VMware Compatibility Guide.
- Installation media: A USB flash drive (8 GB minimum) to create the bootable installer.
- ESXi ISO image: Downloadable from the VMware website (a free version is available).
- Physical or remote access: Access to the server's console (iDRAC, iLO, IPMI) is required for the installation.
Installing ESXi
Step 1: Create a bootable USB drive
Use a tool such as Rufus to create an installation USB drive from the ESXi ISO image you downloaded.
Step 2: Installation on the server
- Boot your server from the USB drive.
- The ESXi installer loads. Press (Enter) to continue.
- Accept the license (EULA) by pressing (F11).
- The installer scans the storage devices. Select the disk on which you want to install ESXi (typically a small SSD, an SD card, or an internal disk).
- Choose the keyboard layout.
- Set a password for the
rootuser. Keep it safe; it is the only account available after installation. - Confirm the installation by pressing (F11).
- Once the installation is complete, remove the USB drive and restart the server.
Installation complete!
The console screen (DCUI - Direct Console User Interface) is displayed with the IP address to manage your host.
The console screen (DCUI - Direct Console User Interface) is displayed with the IP address to manage your host.
Basic Configuration
Step 1: Initial network configuration
On the DCUI console (the yellow and gray screen), you can configure the basic options:
- Press (F2) and enter your root password.
- Go to "Configure Management Network" to set a static IP address, a subnet mask, a gateway, and DNS servers. This is strongly recommended for a production environment.
Step 2: Accessing the web interface (Host Client)
Open a web browser on a machine on the same network and go to the address https://<your-esxi-ip>/. Log in with the root user and your password.
Step 3: Create a virtual machine
- In the web interface, click "Virtual Machines" then "Create/Register VM".
- Choose "Create a new virtual machine".
- Give your VM a name and choose the guest operating system type.
- Select the "datastore" (the storage space) where the VM files will be stored.
- Customize the virtual hardware (CPU, RAM, disk size).
- In the CD/DVD drive settings, select "Datastore ISO file" and upload the ISO of the OS you want to install (e.g., Ubuntu Server).
- Finish the wizard, then start the VM. Open the VM console to proceed with the installation of the guest OS.
Free vs paid license
The free version of ESXi is very functional but cannot be managed by a vCenter Server. Advanced features such as vMotion, HA, DRS, and the centralized backup APIs require a paid license (vSphere Essentials Kit or higher).
The free version of ESXi is very functional but cannot be managed by a vCenter Server. Advanced features such as vMotion, HA, DRS, and the centralized backup APIs require a paid license (vSphere Essentials Kit or higher).
Conclusion
VMware ESXi is the industry standard for server virtualization. Its installation is simple and fast, and its web management interface (Host Client) makes it easy to manage virtual machines on a single host. For larger infrastructures, adding vCenter Server unlocks the full potential of the vSphere ecosystem, but even in its free version, ESXi is an extraordinarily powerful tool for server consolidation and home labs.