In order to upgrade an existing ESX/ESXi server to ESXi 4.1 server you need to either need to be at the local console or have remote access over an appropriate lights-out management card. For our purposes, we'll assume the latter is the case. To properly upgrade the system, you need to fulfill the prerequisite steps as well as perform the actual migration steps both as detailed below:

Prerequisites

1. Download the appropriate ISO image from VMware's website at http://www.vmware.com
2. Sign up for an account or have existing credentials to gain access to the downloads area
3. Lights-Out Management card access with DVD/CDROM capabilities OR
4. Lights-Out Management card access with a localized DVD/CDROM with the ESXi ISO burned and made bootable
5. Configure the BIOS on the server to boot the DVD/CDROM prior to the local disk

Install/Upgrade Procedures

1. Log into iLO/iDRAC of the server you are upgrading
   • Login into the remote system OR
   • In the case of a new install reboot the server
   • Ensure you have either a virtual ISO or physical CDROM in the server to boot from
   • The server should boot off the ISO/CDROM in which will load the boot image where you should get the welcome screen below:
     
     
   • Hit enter to continue on welcome
2. You should see the End User License Agreement screen as pictured below:
   • Accept the EULA by pressing F11
     
     
3. On the Select a Disk screen choose the local disk AND NOT the REMOTE disk
   • If there are no SAN disk currently hooked up to the system you will not see them in the view; only local disk
   • Use the arrow keys to move up and down through the selections if you need to
   • Once you have the target disk selected hit enter
     
     
   • Confirm by pressing enter on the selection you selected previously
     
     
4. The VMware installer will now ask you to confirm that you want to install with your chosen selections
   • To confirm and start the install press f11 on the Confirm Install window
     
     
5. The install will then format and install the necessary binaries and look like the screen below
   
   
6. On the Install Complete screen press enter to complete the installation and reboot
   
   
   
   

Post Installation Configuration

1. Once the server restarts and loads the ESXi software you will be at the welcome screen
   • To configure ESXi so you can get to it remotely press F2
     
     
   • This will bring up the login prompt
   • The default login for a new ESXi build is username: root and password: (blank)
   • Press enter to login whereby you will be dumped into the configuration screen
     
     
2. Once logged into the system there are a few configurations you should configure and are denoted below for each section
   
   
   • Configure Password
     1. Select the Change Password option and press enter
     2. Enter in your password and confirm your choice on the next line
     3. Once complete press enter to confirm and set the new password
        
        
   • Configure Management Network
     1. Hit enter to choose the Configure Management Network option
        
        
        • The Network Adapters option
          1. NOTE - You do not need to configure by default and is beyond the scope of this document. However, this will allow you to choose which interface is used for the management network should you have more than one NIC in the server.
             
             
        • IP Configuration option
          1. Choose the IP Configuration option
          2. In the IP Cnfiguration window enter in the following information:
             • IP Address
             • Subnet Mask
             • Default Gateway
          3. Once complete press enter to save the configuration
             
             
        • DNS Configuration option
          1. Choose the DNS Configuration option
          2. In the DNS Configuration window configure the following information:
             • Set the DNS Server information
             • Set the DNS hostname for the ESXi server
          3. Once complete press enter to save the configuration
             
             
        • Custom DNS Suffixes option
          1. Choose the Custom DNS Suffixes option
          2. In the Custom DNS Suffixes window configure the following information
             • Set the DNS Suffixes separates by a space for each entry
          3. Once complete press enter to save the configuration
             
             
     2. Once all network configuration is doe press ESX from the Configure Management Network screen and the system will prompt you to apply network settings and restart the network
        • Press Y to apply the settings and restart the network
     3. Test Management Network option
        • Choose the Test Management Network option
        • In the Test Management Network windows review the IP's and hostname to test and press enter to run the self-test
        • If all checks out OK the the system is correctly talking on the network and doing DNS resolution
        • Once complete press enter to return to the previous screen
          
          
   • Press ESC to logout of the configuration