Introduction to VMware ESXi

What is VMware ESXi

VMware ESXi is a bare-metal hypervisor developed by VMware, designed to run directly on physical hardware without the need for an underlying operating system. This Type 1 hypervisor is a core component of the VMware vSphere suite, enabling the creation and management of multiple virtual machines (VMs) on a single physical server. VMware ESXi is widely recognized for its reliability and performance in enterprise environments. In this blog post well explore all the features, benefits and limitations of this product in detail.

Overview of Hypervisors

By definition hypervisor is a software, firmware, or hardware that creates and runs virtual machines. It Manages the execution of guest operating systems on a virtual operating platform. Hypervisors are the most important components in virtualization technology. It allows multiple virtual machines (VMs) to run on a single physical host. They manage the distribution of hardware resources among these VMs, enabling efficient and isolated environments for various operating system. Hypervisors are further divided into two major categories, one is called Type-1 hypervisor, and the second one is called Type-2 hypervisor.

Type 1 Hypervisors (Bare-Metal Hypervisors)

These hypervisors run directly on the physical hardware, without needing a host operating system. They manage guest operating systems directly. Examples of this type of hypervisors are VMware ESXi, Microsoft Hyper-V, Citrix XenServer, and KVM. This hypervisor directly accesses the hardware resources results in lower latency and higher efficiency. For security point of view, it reduced attack surface since there is no intermediary OS. These hypervisors are more reliable for enterprise environments due to their direct integration with hardware.

Type 2 Hypervisors (Hosted Hypervisors)

These run on top of an existing operating system as applications. They require the host OS to manage hardware interactions. Popular Type -2 hypervisors are VMware Workstation, Oracle VirtualBox, and Parallels Desktop. These products are simple to set up and manage, making them suitable for individual users, small-scale applications and testing different OS.

Key Differences Between ESXi and ESX

VMware ESXi and ESX are both hypervisors developed by VMware for server virtualization, but they differ significantly in architecture, performance, and management.
ESX utilizes a Linux-based Service Console (COS) for management tasks, which adds complexity and increases the attack surface. While A bare-metal hypervisor that operates without a general-purpose operating system. It features a lightweight architecture with a Direct Console User Interface (DCUI) for management, enhancing security and reducing overhead. ESX requires several gigabytes of disk space due to the Service Console and additional components, while ESXi requires much smaller footprint, typically around 130 MB, making it quicker to install and easier to manage. ESX management is done through the Service Console or remote management tools, which can be less efficient. ESXi Managed primarily through the vSphere Client or vCenter Server, allowing for centralized management of multiple hosts and VMs.

Architecture of VMware ESXi

The architecture of VMware ESXi consists of several critical components that work together to provide virtualization services. We will discuss each component in detail.

VMkernel Overview

The VMkernel is a core component of VMware ESXi, functioning as a lightweight operating system that manages hardware resources and facilitates communication between virtual machines and the physical server. It abstracts the underlying hardware, allowing multiple VMs to operate independently while sharing resources.
It handles CPU scheduling for VMs, optimizing performance by allocating processing time based on demand. It manages input/output operations for storage and network interfaces. VMkernel ports support various types of traffic essential for virtualization operations. i.e. Management Traffic, vMotion Traffic, Storage Traffic, Fault Tolerance Traffic.

Component	Description
VMkernel	The core operating system that manages hardware resources and VM operations.
VMs (Virtual Machines)	Isolated environments that run applications independently on shared hardware.
VMkernel Ports	Virtual network interfaces that enable communication for various services such as management, vMotion, iSCSI, and NFS.
vSwitches (Virtual Switches)	Software-based switches that connect VMs to each other and to external networks. They can be configured with multiple port groups for different traffic types.
Physical NICs (Network Interface Cards)	Physical adapters that connect the ESXi host to external networks; they are essential for uplinking virtual switches to physical networks.
Management Interface	A dedicated VMkernel port used for managing the ESXi host via tools like vCenter Server.

Key Features of VMware ESXi

VMware ESXi offers a range of features aimed at enhancing virtualization efficiency, scalability, and management. VMware ESXi supports significant scalability, allowing organizations to expand their virtual environments seamlessly.
Below is the table of key features VMware offers in the latest version.

Feature	Description
Bare-Metal Hypervisor	Runs directly on hardware without a host operating system, optimizing performance and resource management.
Scalability	Supports up to 768 vCPUs and 24 TB of RAM per VM, with clusters of up to 96 hosts and 10,000 VMs.
Fault Tolerance	Provides zero-downtime failover by maintaining a live shadow instance of VMs on separate hosts.
Resource Management	Features like Distributed Resource Scheduler (DRS) for automated workload balancing across hosts.
Support for Multiple OS	Compatible with various operating systems, including Windows, Linux, and macOS.
Security Features	Includes Secure Boot, VM Encryption, and role-based access control (RBAC) for enhanced security.
Management Tools	Integrates with vCenter Server for centralized management and monitoring of multiple ESXi hosts.
Performance Optimization	Offers features like resource pools and I/O control to ensure efficient resource allocation.
Networking Capabilities	Supports advanced networking options like distributed virtual switches and VLAN tagging.
High Availability	Clustering and vMotion capabilities ensure continuous service availability during maintenance or failures.

Licensing and Versions

VMware Provide a detail list of Licencing and version of ESXi, from testing to Enterprise purpose. We categorize the version based on the license. Here is the detail list.

Licensing Model	Description	Pricing Range	Key Features
Per-Processor Licensing	Licenses sold per processor, covering up to 32 cores. Additional licenses required for more than 32 cores.	Varies (e.g., $995 – $1,250 for Standard)	Basic virtualization features; separate licensing for ESXi hosts and vCenter Server.
Per Core Licensing	Minimum of 16 cores licensed per CPU; subscription-based model.	Varies (e.g., $50 per core for Standard)	Covers multiple physical CPUs on ESXi hosts; supports advanced features based on license type.
vSphere Standard	Ideal for small businesses needing basic features.	$995 – $1,250 per processor	Includes vMotion, High Availability, and Data Protection; lacks advanced features like DRS.
vSphere Enterprise Plus	Suited for large enterprises requiring full feature set.	$3,495 – $4,250 per processor	Adds Distributed Switch, Host Profiles, Auto Deploy, and advanced DRS; greater scalability options.
vSphere with Operations Management	Combined package including operations management tools.	Around $4,245 per processor	Enhanced monitoring and management capabilities; higher support costs.
vSphere Essentials Plus Kit	Designed for small environments with a maximum of 3 hosts.	Sold as a 96-core kit ($35 per core)	Basic features suitable for smaller deployments; includes vCenter Server Essentials.
vSphere+ Subscription Licensing	Subscription-based model that leverages cloud capabilities while managing on-premises infrastructure.	Varies	Offers flexibility in licensing and management of resources across environments.

Installation and Configuration

In this step we will install and configure ESXi. Installing and configuring VMware ESXi involves several steps to ensure a successful setup. It can be installed on both VMware workstation and on Physical machine too. for this blog post we will install it on VMware Workstation. A link is given, where VMware workstation can be downloaded. Click on the link to download ESXi iso image.
Ensure that your system meets the minimum hardware specifications for ESXi installation, including CPU, RAM, and storage requirements. Once the ISO is downloaded, Open the Workstation application to start the installation process.
Click on start button to start the installation process.

Click inter continue button to process next.

Press F11 to accept the license agreement.

Select the storage and Press enter to continue. If your system has more than one storage drive, then select it accordingly.

Select the keyboard, which is US default.

Enter a strong root password to secure the ESXi host. Review your settings and confirm the installation.

The installer will repartition the selected disk, erasing all existing data on it. Press F11 to start the installation.

After installation, reboot the server and remove the installation media when prompted. The system will boot into ESXi.

Initial Configuration

As the ESXi boot for the first time, access the DCUI by pressing F2 and entering the root credentials.

Set up network configurations by navigating to the network settings in the DCUI. Assign an IP address, subnet mask, and gateway as needed. For remote management, enable SSH access through the DCUI for easier administration.

Configure a hostname for your ESXi host and set up DNS servers to ensure proper name resolution in your network environment.

Click here to read more about how to change Hostname in ESXI

Post-Installation Tasks

Install any additional software or drivers needed for specific hardware functionalities (e.g., NVIDIA VIBs, VMware tools). Review and configure firewall settings to allow necessary traffic for management and VM operations.

Management Tools

After installation, manage your ESXi host through various interfaces:

Use the vSphere Client or ESXi Host Client for ongoing management tasks. Consider integrating with vCenter Server for centralized management if deploying multiple hosts. Type the IP address of the ESXi that we assigned during the initial configuration.

Creating Virtual Machines

Creating and managing virtual machines (VMs) in VMware ESXi can be accomplished through various interfaces, including the vSphere Client, VMware Host Client, and PowerCLI. For this blog post we will access it through web browser. Enter the IP address of ESXi in Browser and hit enter. Type username and password. Press enter.

Navigate to Hosts and Clusters, select your data center, and choose the ESXi host where you want to create the VM.

Click on Actions > New Virtual Machine to open the New VM Wizard.

Choose Create a new virtual machine and click Next

Enter a unique name for the VM and select a folder for organization. I assigned vm-1 name to our virtual machine.

Choose the ESXi host or cluster for the VM.

Choose a datastore where the VM files will be stored, ensuring sufficient free space.

Customize CPU, memory, and disk settings as needed. For this blog post we assigned 2 CPU core and 4GB memory this VM.

Choose the guest operating system family and version. Review all settings and click Finish to create the VM.

Follow similar steps as above to configure the VM’s name, OS, storage, and hardware settings. We can increase or decrease the CPU core, RAM and storage per our requirement.

Managing Virtual Machines

Use the vSphere Client or Host Client to power on, power off, suspend, or reset VMs as needed. You cannot change the settings of VM if it is in running state. Once the VM is powered off we can adjust CPU and memory resources through the VM settings to optimize performance based on workload requirements. Configure network settings by selecting appropriate virtual switches or VLANs for network connectivity.

Manage virtual disks by adding or removing disks, changing disk types (thick/thin), or migrating disks to different datastores.

Create snapshots for backup purposes or before making significant changes to VMs, allowing easy rollback if necessary.

Automation Using PowerCLI

For bulk VM creation or management tasks:

Install VMware PowerCLI on your management workstation. Use scripts to automate tasks such as creating multiple VMs with predefined configurations.

# Connect to ESXi host
Connect-VIServer -Server <ESXi_IP> -User <username> -Password <password>
# Create a new VM New-VM -Name “NewVM” -ResourcePool “Resources” -Datastore “datastore1” -MemoryGB 4 -NumCpu 2 -GuestId “windows9Guest”

The above script connects to an ESXi host and creates a new Windows VM with specified resources.

Networking in VMware ESXi

Networking in VMware ESXi is crucial for ensuring that virtual machines (VMs) can communicate with each other and with external networks. This involves configuring virtual switches, port groups, and VMkernel ports.

Virtual Switches (vSwitches)

vSwitch (Virtual Switch): A software-based switch that allows VMs to communicate with each other and with external networks. vSwitch0 is the default switch created during installation, typically used for management traffic. Additional vSwitches Can be created for specific traffic types, such as storage or vMotion. Virtual switches further divided into two types.

1. Standard Virtual Switch (vSwitch)

Configured on a single ESXi host, allowing multiple VMs to share a physical NIC. By default, it has 120 ports, expandable up to 4096 ports per host.

2. Distributed Virtual Switch (dvSwitch)

Managed through vCenter Server, allowing centralized management across multiple hosts. It can support up to 60,000 ports and maintains consistent settings across hosts.

Port Groups

Port groups are used to define a set of network policies for VMs that connect to a specific vSwitch. To add a new port group, navigate to the networking section in the ESXi interface and select the appropriate vSwitch. Assign VLAN IDs to segment traffic logically, allowing multiple networks to coexist on the same physical infrastructure without interference.

VMkernel Ports

VMkernel ports are used for management traffic, vMotion, iSCSI storage, and other ESXi services.

Storage Management

Effective storage management in VMware ESXi involves selecting appropriate storage types, creating and managing datastores, applying storage policies, configuring multipathing, optimizing performance, and ensuring robust backup solutions. By leveraging these features, administrators can enhance the efficiency and reliability of their virtualized environments.

There are different types of storage management options available for ESXi. VMware ESXi supports various storage options to meet different data center needs:

Storage Type	Description
VMFS (Virtual Machine File System)	A high-performance file system designed for storing virtual machine files. VMFS allows multiple ESXi hosts to access the same datastore simultaneously.
NFS (Network File System)	Provides a shared storage solution over the network, allowing VMs to access files stored on an NFS server.
Fibre Channel SAN	Utilizes Fibre Channel technology to connect storage devices directly to servers, providing high-speed data transfer.
iSCSI SAN	Uses standard Ethernet networks to connect storage devices, enabling block-level access to storage resources.
vSAN (Virtual SAN)	A software-defined storage solution that aggregates local storage from multiple ESXi hosts into a single datastore.

Datastore Management

Datastore management in VMware ESXi is essential for effectively storing and organizing virtual machine files. Datastores serve as logical containers that abstract the underlying physical storage, allowing for seamless management of virtual disks.

Types

VMFS (Virtual Machine File System): A high-performance file system optimized for storing virtual machines on block storage devices. VMFS allows multiple ESXi hosts to access the same datastore concurrently, making it suitable for clustered environments.

NFS (Network File System): Provides shared storage over a network, allowing VMs to access files stored on an NFS server.

Conclusion

In conclusion, VMware ESXi stands out as a robust and versatile bare-metal hypervisor that plays a pivotal role in modern virtualization environments. Its ability to efficiently manage resources, support various storage and networking configurations, and provide high levels of security makes it an ideal choice for organizations looking to optimize their IT infrastructure. By leveraging features such as Storage DRS, vMotion, and advanced networking capabilities, organizations can enhance their operational efficiency while ensuring business continuity.Ultimately, embracing virtualization with VMware ESXi not only streamlines resource management but also positions businesses for future growth in an increasingly digital landscape.

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