VMware ESXi Host Configuration, Management, and Troubleshooting

This comprehensive guide provides a detailed overview of VMware ESXi host configuration, management, and troubleshooting, including how to join ESXi hosts to a vSphere cluster. It is designed for IT professionals and system administrators who are responsible for managing and maintaining VMware ESXi hosts.

ESXi Architecture and Components

Understanding the architectural foundation of ESXi is crucial for effective troubleshooting and performance optimization12. ESXi is a bare-metal hypervisor that runs directly on the server hardware, with the VMkernel as its core component. This high-performance microkernel is specifically optimized for virtualization3. The VMkernel manages resource allocation, scheduling, and the interaction between virtual machines and the underlying hardware1.

Key components within the ESXi architecture include:

• Direct Console User Interface (DCUI): This interface provides a low-level configuration and management platform accessible through the server's console. It is primarily used for initial configuration tasks, such as setting the root password, configuring the management network, and enabling SSH access1.

• Virtual Machine Monitor (VMM): This component provides the necessary execution environment for virtual machines. It includes a helper process known as vmx. Each active virtual machine has its own dedicated VMM and vmx process1.

• VMware Agents: These agents facilitate high-level management of the VMware infrastructure from remote applications. Key agents include the host agent (hostd) and the vCenter agent (vpxa)1.

Initial ESXi Host Configuration

After the ESXi installation is complete, the initial configuration of the host is performed using the DCUI. This involves several key steps:

1. Setting the root password: Establishing a strong root password is fundamental for securing the ESXi host1.

2. Configuring the management network: This step involves configuring essential network settings, including the IP address, subnet mask, default gateway, and DNS server information. In production environments, it is strongly recommended to use a static IP address for the management network to ensure consistent accessibility1.

3. Enabling SSH access: Enabling SSH access allows for secure remote management of the ESXi host using a secure shell1.

4. ESXi Passwords and Account Lockout: ESXi provides mechanisms for password management and account lockout policies to enhance security. These policies can be configured to enforce password complexity requirements, password expiration intervals, and account lockout thresholds to prevent unauthorized access4.

5. About ESXi Evaluation and Licensed Modes: ESXi is available in both evaluation and licensed modes. The evaluation mode provides a limited-time trial of the full ESXi feature set, while the licensed mode requires a valid license key for continued use4.

6. Licensing ESXi Hosts After Upgrade: After upgrading an ESXi host, it is necessary to apply a new license key to ensure continued operation in licensed mode4.

7. Run the Secure Boot Validation Script After ESXi Upgrade: Following an ESXi upgrade, it is recommended to run the secure boot validation script to verify the integrity of the boot process and ensure that the host is protected against malicious bootloaders or modified system files4.

Enabling Lockdown Mode provides significant security benefits by restricting direct access to the ESXi host. In Lockdown Mode, only users with specific permissions granted through vCenter Server can log in to the host, preventing unauthorized modifications or access to sensitive information5.

ESXi System Configuration

This section provides an overview of ESXi system configuration, including storage, hardware requirements, and remote management options.

ESXi System Storage Overview

ESXi utilizes system storage for various purposes, including storing the hypervisor, log files, and scratch space. The scratch partition is a dedicated area on the disk used for temporary files and diagnostic data. It is important to ensure that the scratch partition has sufficient space to prevent performance issues or system instability. The scratch partition can be configured from the vSphere Client4.

ESXi Hardware Requirements

ESXi has specific hardware requirements that must be met for optimal performance and stability. These requirements include:

• Processor: ESXi supports a wide range of processors from Intel and AMD. The specific processor requirements vary depending on the ESXi version and features being used.

• Memory: ESXi requires a minimum amount of memory to operate, and the recommended amount varies depending on the number of virtual machines and their resource requirements.

• Storage: ESXi supports various storage technologies, including local disks, SAN, and NAS. The specific storage requirements depend on the storage capacity and performance needs of the virtual machines.

• Network: ESXi requires at least one network adapter for management traffic. Additional network adapters may be required for vMotion, storage traffic, and virtual machine network connectivity4.

Network Installation

This section covers the installation of ESXi over a network, including network booting and scripted installation.

Network Booting the ESXi Installer

Network booting allows for installing ESXi without the need for a physical CD/DVD or USB drive. This method is particularly useful for deploying ESXi on multiple hosts or in environments where physical media is not readily available. The network boot process involves using PXE (Preboot Execution Environment) and a TFTP (Trivial File Transfer Protocol) server to load the ESXi installer over the network4.

Scripted ESXi Installation

Scripted installation enables automating the ESXi installation process, reducing manual intervention and ensuring consistency across multiple deployments. Installation scripts can be used to pre-configure various settings, such as network configuration, partitioning, and licensing. This method is particularly useful for large-scale deployments or for creating standardized ESXi installations4.

Provisioning ESXi Systems with vSphere Auto Deploy

vSphere Auto Deploy provides a stateless and automated method for provisioning ESXi hosts. With Auto Deploy, ESXi hosts are booted over the network and configured based on image profiles stored in vCenter Server. This simplifies ESXi deployments and allows for centralized management of host configurations4.

ESXi Host Management

ESXi hosts can be managed through various interfaces, each offering different capabilities and levels of access:

• vSphere Client: The vSphere Client is a web-based interface that provides centralized management of ESXi hosts and virtual machines. It allows administrators to perform various tasks, such as creating and managing virtual machines, configuring networking, and monitoring resource usage6.

• vSphere Host Client: The vSphere Host Client is a client-server application that allows for managing a single ESXi host. It provides a more focused interface for managing host-specific settings and performing tasks such as configuring storage, managing networking, and troubleshooting issues4.

• ESXCLI: ESXCLI is a command-line interface that provides a comprehensive set of commands for managing and configuring ESXi hosts. It offers granular control over various aspects of the host and is often used for scripting and automation tasks3. In addition to configuration and management, ESXCLI can also be used to perform ESXi host updates and upgrades2.

• PowerCLI: PowerCLI is a PowerShell-based command-line interface for managing VMware vSphere environments. It provides a powerful scripting environment for automating tasks, managing virtual machines, and configuring ESXi hosts2.

• Using Remote Management Applications: ESXi supports various remote management applications, including the vSphere Client, vSphere Host Client, and third-party tools. These applications allow administrators to manage ESXi hosts from remote locations, providing flexibility and convenience4.

• VMware Host Client System Requirements: The VMware Host Client has specific system requirements that must be met to ensure proper functionality. These requirements include a supported web browser, operating system, and network connectivity4.

ESXi Troubleshooting

Troubleshooting ESXi hosts often involves a combination of analyzing log files, monitoring performance metrics, and utilizing various command-line tools.

Log Files

ESXi generates a variety of log files that provide valuable insights into the operation of the host and can be instrumental in diagnosing issues. Some of the key log files include:

• /var/log/vmkernel.log: This log file contains information related to the VMkernel, including device discovery, storage and networking device driver events, and virtual machine startup1.

• /var/log/hostd.log: This log file contains information specific to the host agent (hostd), which is responsible for communication between the ESXi host and vCenter Server7.

• /var/log/vpxa.log: This log file contains information related to the vCenter agent (vpxa), which is responsible for managing the ESXi host within the vCenter Server environment7.

Performance Monitoring

ESXi provides performance monitoring tools that enable administrators to track resource usage and identify potential bottlenecks that may be impacting performance. The esxtop command-line tool is a powerful utility that provides real-time performance statistics for CPU, memory, storage, and network8.

Troubleshooting Tools

ESXi offers a range of command-line tools that can be used to diagnose and resolve issues. Some of the commonly used tools include:

• esxcli: This command-line interface provides a comprehensive set of commands for managing and configuring ESXi hosts. It offers granular control over various aspects of the host and is often used for scripting and automation tasks3.

• net-stats: This tool collects port statistics and provides detailed insights into network activity, which can be helpful in diagnosing network-related issues9.

• pktcap-uw: This tool allows for capturing network frames at the uplink, vSwitch, or virtual port levels, providing a deeper understanding of network traffic flow and potential problems9.

• nc: NetCat is a versatile tool that can be used for various network-related tasks, including verifying connectivity on a specific port9.

• iperf: This bandwidth tool is used to test network performance and identify potential bottlenecks. It is particularly valuable for proactive network performance testing in vSAN environments to ensure optimal storage performance9.

Common Troubleshooting Scenarios

This section provides an overview of common troubleshooting scenarios encountered in ESXi environments.

• Virtual machine performance issues: Performance issues in virtual machines can stem from various factors, including CPU or memory contention, storage latency, or network latency. Troubleshooting these issues often involves analyzing resource usage, identifying bottlenecks, and optimizing virtual machine configurations8.

• CPU limiting: Check if the virtual machine is constrained by CPU limits set on itself or by its resource pool8.

• Memory load: Ensure sufficient physical RAM on the host or decrease the amount of RAM allocated to virtual machines8.

• Ballooning and swapping: Monitor memory ballooning and swapping using esxtop to identify potential memory contention issues8.

• Storage latency: Investigate storage-related performance issues by migrating virtual machines to different storage locations, reducing the number of virtual machines per LUN, and checking for SCSI reservation conflicts8.

• Network latency: Use tools like iperf to measure network latency and identify potential network bottlenecks8.

• ESXi host not responding: When an ESXi host becomes unresponsive, it can disrupt virtual machine operations and require immediate attention. Troubleshooting this issue typically involves checking network connectivity, restarting management agents, and analyzing log files for errors7.

• Validate troubleshooting steps: Follow a systematic approach to validate each troubleshooting step and eliminate possible causes7.

• Verify accessibility: Ensure that the ESXi host is accessible from vCenter Server or the vSphere Client7.

• Reconnect the host: Attempt to reconnect the ESXi host to vCenter Server to see if it resolves the issue7.

• Verify IP address: Confirm that the ESXi host is responding to vCenter Server at the correct IP address7.

• Check network connectivity: Verify network connectivity between vCenter Server and the ESXi host using ping and telnet7.

• Restart management agents: Restart the ESXi management agents to resolve potential communication issues7.

• Check the hostd process: Verify if the hostd process is running and responding on the ESXi host7.

• Verify for a purple diagnostic screen: Check if the ESXi host has experienced a purple diagnostic screen, which indicates a critical error7.

• vSAN cluster issues: vSAN clusters can experience various issues that can impact storage performance and availability. Troubleshooting these issues often involves checking power-related problems, host communication issues, and critical vSAN configuration parameters10.

• Power-related problems: Ensure reliable power sources and UPS systems for ESXi hosts to prevent unexpected shutdowns or restarts10.

• Uncooperative hosts: Address situations where an ESXi host fails to rejoin the vSAN cluster after a restart10.

• Virtual machine inaccessibility: Investigate cases where virtual machines become inaccessible due to host communication issues10.

• Host communication blockage: Troubleshoot situations where hosts in the vSAN cluster are unable to communicate with each other10.

• Critical vSAN configuration parameters: Verify the configuration of critical vSAN parameters, such as DOMPauseAllCCPs and IgnoreClusterMemberListUpdates, to ensure proper cluster operation10.

Deep Dive Troubleshooting

This section delves deeper into ESXi troubleshooting, covering advanced tools, techniques, and concepts.

Troubleshooting Tools Importance

Knowing how to effectively use the available troubleshooting tools is essential for resolving ESXi issues efficiently. These tools include the graphical user interface (GUI), command-line interfaces (CLI), and log files. Understanding the ESXi architecture and its components is crucial for narrowing down the source of problems and taking appropriate troubleshooting steps2.

ESXi Architecture and Components

A deep understanding of the ESXi architecture and its components is essential for effective troubleshooting. This includes knowledge of the VMkernel, VMM, VMware agents, and other core components2.

ESXi Log Files

ESXi log files provide a wealth of information for troubleshooting. Analyzing log files can help identify the root cause of issues and guide administrators towards appropriate solutions2.

ESXi Commands

ESXi offers a wide range of commands for managing, configuring, and troubleshooting the host. Familiarity with these commands is essential for performing various administrative tasks2.

Monitoring and Configuring ESXi Server Settings

ESXi provides tools and interfaces for monitoring and configuring server settings, such as network configuration, storage settings, and security policies2.

Monitoring Core ESXi Performance

Monitoring core ESXi performance metrics, such as CPU usage, memory utilization, and storage I/O, is crucial for identifying potential performance bottlenecks and ensuring optimal resource allocation2.

ESXi Troubleshooting Frequently Used Commands

Certain ESXi commands are frequently used for troubleshooting purposes. These commands provide information about system status, resource usage, and configuration settings2.

ESXi Configuration Files

ESXi configuration files store various settings and parameters that control the behavior of the host. Understanding these files can be helpful for troubleshooting and customizing ESXi configurations2.

Performance Optimization

This section focuses on optimizing ESXi performance by configuring various settings and following best practices.

Recommendations for Enhanced ESXi Performance

VMware provides recommendations for enhancing ESXi performance, including optimizing CPU and memory settings, configuring storage for optimal I/O, and tuning network parameters4.

Incoming and Outgoing Firewall Ports for ESXi Hosts

ESXi utilizes firewalls to control network traffic to and from the host. It is important to configure the firewall rules to allow necessary traffic while blocking unauthorized access4.

Required Free Space for System Logging

ESXi requires sufficient free space for system logging to ensure that log files can be written without interruption. Inadequate free space can lead to log truncation and loss of valuable diagnostic information4.

Power Policy Options in ESXi

ESXi provides power policy options that allow administrators to control the power consumption of the host. These policies can be configured to balance performance and energy efficiency based on the specific needs of the environment11.

ESXi Memory Considerations

Memory management is crucial for ESXi performance. Understanding memory sizing, overcommit techniques, page sharing, and swapping optimizations can help administrators configure ESXi memory settings for optimal resource utilization11.

General ESXi Networking Considerations

ESXi networking involves various considerations, including Network I/O Control (NetIOC), DirectPath I/O, Single Root I/O Virtualization (SR-IOV), and SplitRx mode. These features can be configured to optimize network performance and resource allocation11.

Joining ESXi Hosts to a vSphere Cluster

vSphere clusters provide numerous benefits, including high availability, resource management, and simplified management for ESXi hosts512. By grouping ESXi hosts into a cluster, administrators can leverage features such as vSphere DRS (Distributed Resource Scheduler) for automated load balancing and vSphere HA (High Availability) for automatic failover in case of host failures.

To join ESXi hosts to a vSphere cluster, follow these steps:

1. Create a datacenter in vCenter Server: The datacenter object serves as a container for all the objects in the virtual infrastructure, including hosts, virtual machines, networks, and datastores5.

2. Add ESXi hosts to the datacenter: ESXi hosts can be added to the datacenter by providing the host's IP address or FQDN and the root credentials5.

3. Create a cluster in the datacenter: A cluster is created within the datacenter and assigned a name. Cluster features, such as vSphere DRS and vSphere HA, can be enabled during cluster creation5.

4. Add ESXi hosts to the cluster: ESXi hosts can be added to the cluster by dragging and dropping them from the datacenter inventory to the cluster or by using the "Add Host" wizard13.

5. Adding an ESXi host to the VMware vCenter: Log in to the vSphere Client, navigate to the "Hosts and Clusters" view, and use the "Add Host" wizard to add the ESXi host to the vCenter Server inventory6.

6. Configuring VMware ESXi cluster: Ensure that the ESXi hosts meet the cluster requirements, including compatible processors, shared storage, and dedicated networks for cluster management, vMotion, and storage traffic5.

7. What is an ESXi cluster and how do you cluster ESXi servers?: Understand the components of an ESXi cluster, including ESXi hosts, virtual machines, and shared storage, as well as the advantages of clustering, such as high availability and load balancing12.

8. Deploying VMware vCenter Server 6.7u2 and vSphere clustering configuration: Follow the steps to deploy vCenter Server and configure vSphere clustering, including creating a vSphere cluster, adding ESXi hosts to the cluster, and configuring coredump on the ESXi hosts14.

9. Nodes in VMware vSphere cluster: Understand the concept of nodes in a vSphere cluster, which represent the ESXi hosts that are part of the cluster. Cluster features, such as DRS and HA, operate at the cluster level and affect all the nodes within the cluster13.

Use Case Scenarios

This section presents use case scenarios that illustrate common configuration and troubleshooting tasks in ESXi environments.

• Scenario 1: Troubleshooting virtual machine network connectivity: A virtual machine is unable to connect to the network. The administrator starts by checking the virtual machine's network settings and verifying that it is connected to the correct virtual switch. They then use the esxtop network view to monitor network traffic on the ESXi host and identify any potential issues, such as high network latency or dropped packets. To further investigate the issue, the administrator uses the pktcap-uw tool to capture network frames at the virtual machine's vNIC level and analyze the captured traffic for any anomalies. By analyzing the captured frames, the administrator identifies that the virtual machine's MAC address is not being learned by the physical switch. They resolve the issue by configuring the physical switch port to allow the virtual machine's MAC address.

• Scenario 2: Resolving an ESXi host not responding issue: An ESXi host is showing as "not responding" in vCenter Server. The administrator begins by checking the network connectivity between vCenter Server and the ESXi host using ping. They then attempt to connect to the ESXi host directly using the vSphere Host Client to verify if the host is accessible. If the host is accessible, the administrator restarts the management agents on the ESXi host using the services.sh restart command. They then analyze the hostd.log file for any error messages that might indicate the cause of the issue. In this case, the administrator finds an error message related to a storage connectivity problem. They resolve the issue by addressing the underlying storage problem, which restores communication between the ESXi host and vCenter Server.

• Scenario 3: Optimizing vSAN cluster performance: A vSAN cluster is experiencing performance issues. The administrator starts by checking the vSAN health status in the vSphere Client and reviewing performance metrics. They then examine the configuration of critical vSAN parameters, such as DOMPauseAllCCPs and IgnoreClusterMemberListUpdates, to ensure they are set correctly. The administrator also monitors resyncing objects in the vSAN cluster to identify any excessive resync activity that might be impacting performance. To further investigate the issue, they perform a VM creation test on each host in the cluster to compare the time it takes to create a virtual machine. This test reveals that one of the hosts is significantly slower than the others, indicating a potential hardware or configuration issue on that specific host. The administrator then focuses their troubleshooting efforts on that host to identify and resolve the underlying problem.

Best Practices for ESXi Configuration and Management

Following best practices for ESXi configuration and management is crucial for ensuring the optimal performance, stability, and security of the virtualized environment. Here are some key recommendations:

• Use a static IP address for the management network: Assigning a static IP address to the management network ensures consistent accessibility to the ESXi host and prevents potential connectivity issues that may arise from DHCP address changes1.

• Enable SSH access for remote management: Enabling SSH access provides a secure method for remotely managing the ESXi host, allowing administrators to perform tasks, troubleshoot issues, and apply updates without requiring physical access to the server1.

• Regularly update ESXi hosts with the latest patches: Keeping ESXi hosts up to date with the latest patches is essential for addressing security vulnerabilities, improving stability, and ensuring compatibility with other VMware components. VMware regularly releases patches and updates that address known issues and enhance the functionality of ESXi. Applying these updates in a timely manner is crucial for maintaining a secure and stable environment.

• Monitor ESXi host performance using esxtop and other tools: Regularly monitoring ESXi host performance using tools like esxtop allows administrators to track resource usage, identify potential bottlenecks, and proactively address performance issues before they impact virtual machine operations8.

• Configure system logging to capture relevant events: Configuring system logging to capture relevant events provides valuable diagnostic information for troubleshooting issues and understanding the behavior of the ESXi host4.

• Use vSphere clusters for high availability and resource management: Utilizing vSphere clusters provides high availability for virtual machines through features like vSphere HA and enables efficient resource management through vSphere DRS5.

• Follow VMware's best practices for hardware compatibility and configuration: Adhering to VMware's best practices for hardware compatibility and configuration ensures that the ESXi host is running on supported hardware and is configured optimally for performance and stability11.

Advanced ESXi Configuration and Troubleshooting

Advanced ESXi configuration involves modifying advanced settings that can affect the behavior of various components within the ESXi host. These settings can be accessed through the vSphere Client, ESXCLI, or the local console3. Modifying advanced settings can be used to fine-tune ESXi performance and address specific requirements3. However, it is important to exercise caution when modifying these settings, as incorrect configurations can lead to unexpected behavior or system instability.

Advanced troubleshooting techniques may involve analyzing core dumps, which are memory snapshots taken during system crashes, to diagnose the cause of the crash. The vm-support command can be used to collect diagnostic information from the ESXi host, which can be helpful for troubleshooting complex issues. In some cases, it may be necessary to engage VMware support for assistance with advanced troubleshooting.

Alternatives to ESXi

While ESXi is a widely used hypervisor, there are alternative solutions available that may be suitable for certain environments or use cases. One such alternative is LXD (Linux Container Daemon), an open-source container and virtual machine manager. LXD provides a lightweight and efficient platform for running containers and virtual machines on Linux systems.

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Conclusion

This guide has provided a comprehensive overview of VMware ESXi host configuration, management, and troubleshooting. By understanding the ESXi architecture, utilizing the available management tools, and following best practices, administrators can ensure the optimal performance, stability, and security of their ESXi hosts and virtualized environments. Proper configuration, management, and troubleshooting are essential for maintaining a healthy and efficient VMware ESXi environment.

To further enhance your knowledge and skills in managing VMware ESXi, explore the resources and tools mentioned in this guide, including the official VMware documentation, knowledge base articles, and community forums. Consider enrolling in the VMware ESXi course outlined in 16 for a structured learning experience. By continuously expanding your knowledge and staying up to date with the latest advancements in VMware technologies, you can effectively manage and maintain your ESXi environment and ensure the smooth operation of your virtualized workloads.

Works cited

1. 5. Mastering ESXi Host Configuration and Management | Step-by-Step Guide - YouTube, accessed on February 12, 2025, https://m.youtube.com/watch?v=g5fwp9QNkTc&t=4933s

2. 6. VMware ESXi Deep Dive Troubleshooting: Commands, Config Files & Logs - YouTube, accessed on February 12, 2025, https://m.youtube.com/watch?v=Wobgouu017Y&pp=ygUHI2VzeHRvcA%3D%3D

3. Configuring advanced options for ESXi - Broadcom support portal, accessed on February 12, 2025, https://knowledge.broadcom.com/external/article/310338/configuring-advanced-options-for-esxi.html

4. ESXi Installation and Setup - Broadcom Techdocs - Broadcom Inc., accessed on February 12, 2025, https://techdocs.broadcom.com/us/en/vmware-cis/vsphere/vsphere/8-0/esxi-installation-and-setup-8-0.html

5. Steps to Configure a VMware ESXi Cluster - NAKIVO, accessed on February 12, 2025, https://www.nakivo.com/blog/configuring-vmware-esxi-cluster/

6. Adding an ESXi host to the VMware vCenter - Dell Technologies Info Hub, accessed on February 12, 2025, https://infohub.delltechnologies.com/es-es/l/deployment-guide-dell-emc-powerflex-with-dell-emc-poweredge-mx7000-chassis/adding-an-esxi-host-to-the-vmware-vcenter/

7. Troubleshooting an ESXi host in a "not responding" state, accessed on February 12, 2025, https://knowledge.broadcom.com/external/article/344682/troubleshooting-an-esxi-host-in-a-not-re.html

8. Troubleshooting ESX/ESXi virtual machine performance issues, accessed on February 12, 2025, https://knowledge.broadcom.com/external/article/304594/troubleshooting-esxesxi-virtual-machine.html

9. ESXi Network Troubleshooting Tools - VMware vSphere Blog, accessed on February 12, 2025, https://blogs.vmware.com/vsphere/2018/12/esxi-network-troubleshooting-tools.html

10. Essential vSAN Troubleshooting: ESXi Host Guide - andysworld!, accessed on February 12, 2025, https://andysworld.org.uk/2024/09/18/essential-vsan-troubleshooting-esxi-host-guide/

11. www.vmware.com, accessed on February 12, 2025, https://www.vmware.com/docs/vsphere-esxi-vcenter-server-80-performance-best-practices

12. What is an ESXi cluster, and how do you cluster ESXi servers - LogicMonitor, accessed on February 12, 2025, https://www.logicmonitor.com/blog/what-is-an-esxi-cluster-and-how-do-you-cluster-esxi-servers

13. How to add ESXi 8.0 hosts to the vCenter 8.0 Cluster? | Key Features - YouTube, accessed on February 12, 2025, https://www.youtube.com/watch?v=8YrVBh4iptM

14. VMware vCenter Server 6.7U2 and vSphere clustering configuration - NetApp, accessed on February 12, 2025, https://docs.netapp.com/us-en/flexpod/express/express-c-series-c190-deploy_vmware_vcenter_server_6.7u2_and_vsphere_clustering_configuration.html

15. ESXi Alternative: try open source LXD - Ubuntu, accessed on February 12, 2025, https://ubuntu.com/blog/esxi-alternative

16. Basic ESXi configuration | VMware ESXi# - Geek University, accessed on February 12, 2025, https://geek-university.com/basic-esxi-configuration/