Performing Post-installation Configuration

Whether you are installing from a DVD or performing an unattended installation of ESX, once the installation is complete, there are several post-installation changes that either must be done or are strongly recommended. Among these configurations are changing the physical NIC used by the Service Console/management network, adjusting the amount of RAM allocated to the Service Console, and configuring an ESX/ESXi host to synchronize with an external NTP server.

Changing the Service Console/Management NIC

During the installation of ESX, the NIC selection screen creates a virtual switch-also known as a vSwitch-bound to the selected physical NIC. The tricky part, depending upon your server hardware, can be choosing the correct physical NIC connected to the physical switch that makes up the logical IP subnet from which the ESX host will be managed. Although the ESX 4 installation program makes it a little bit easier to distinguish between NICs, ESXi doesn't even give the user the option to select the NIC that should be used for the management network, which is ESXi's equivalent to the Service Console in ESX.

This makes it very possible for the wrong NIC to be selected for the management network. In either situation, if the wrong NIC is selected, the server will be inaccessible via the network. The following figure shows the structure of the virtual networking when the wrong NIC is selected and when the correct NIC is selected.

The simplest fix for this problem is to unplug the network cable from the current Ethernet port in the back of the server and continue trying the remaining ports until the web page is accessible.

The problem with this solution is that it puts a quick end to any type of documented standard that dictates the physical connectivity of the ESX/ESXi hosts in a virtual environment. Is there a better fix? Absolutely! Of course, if you like installations, go for it.

Fixing the management nic in ESXi

Because there is no Service Console in ESXi, fixing an incorrect assignment of the NIC assigned to the management network is handled quite differently than in ESX. Fortunately, VMware anticipated this potential problem and provided a menu-driven system whereby you can fix it. Perform the following steps to fix the management NIC in ESXi:

• Access the console of the ESXi host, either physically or via a remote console solution such as HP iLO.

• On the ESXi home screen, press F2 to customize the system. If a root password has been set, enter that root password.

• From the System Customization menu, select Configure Management Network, and press Enter.

• From the Configure Management Network menu, select Network Adapters, and press Enter.

• Use the spacebar to toggle which network adapter or adapters will be used for the system's management network. Press Enter when finished.

• Press Esc to exit the Configure Management Network menu. When prompted to apply changes and restart the management network, press Y.

• Press Esc to log out of the System Customization menu and return to the ESXi home screen.

After the correct NIC has been assigned to the ESXi management network, the System Customization menu provides a Test Management Network option to verify network connectivity.

Adjusting the Service Console Memory (ESX Only)

Because ESXi omits the Service Console, this section applies only to ESX. Adjusting the amount of memory given to the Service Console is not mandatory but is strongly recommended if you have to install third-party applications into the Service Console. These third-party applications will consume memory available to the Service Console. As noted earlier, the Service Console is granted 300MB of RAM by default, with a hardcoded maximum of 800MB.

The difference of 500MB is, and should be, negligible in relation to the amount of memory in an ESX host. Certainly an ESX host in a production network would not have less than 8GB of memory, and more likely it would have 32GB, 64GB, or even 128GB. So, adding 500MB of memory for use by the Service Console does not place a significant restriction on the number of virtual machines a host is capable of running because of a lack of available memory.

Perform the following steps to increase the amount of memory allocated to the Service Console:

1. Use the vSphere Client to connect to an ESX host or a vCenter Server installation.

2. Select the appropriate host from the inventory tree on the left, and then select the Configuration tab from the details pane on the right.

3. Select Memory from the Hardware menu.

4. Click the Properties link.

5. Enter the amount of memory to be allocated to the Service Console in the text box, and then click the OK button. The value entered must be between 256 and 800.

6. Reboot the ESX host.

Best practices call for the ESX swap partition to be twice the size of the available RAM, which is why I recommended earlier in this chapter to set the size of the swap partition to 1600MB (twice the maximum amount of RAM available to the Service Console). If you didn't size the swap partition appropriately, you can create a swap file on an existing Service Console partition.

Given the ease with which you can simply reinstall VMware ESX, especially if you are using an unattended installation script, I don't recommend creating a swap file in this manner. Instead, simply rebuild the ESX host, and set the Service Console partitions to the recommended sizes during installation.

Configuring Time Synchronization

Time synchronization in ESX/ESXi is an important configuration because the ramifications of incorrect time run deep. While ensuring ESX/ESXi has the correct time seems trivial, time synchronization issues can affect features such as performance charting; SSH key expirations, NFS access, backup jobs, authentication, and more. After the installation of ESX/ESXi Installable or during an unattended installation of ESX using a kickstart script, the host should be configured to perform time synchronization with a reliable time source. This source could be another server on your network or a time source located on the Internet. For the sake of managing time synchronization, it is easiest to synchronize all your servers against one reliable internal time server and then synchronize the internal time server with a reliable Internet time server.

The simplest way to configure time synchronization for ESX/ESXi involves the vSphere Client, and the process is the same for both ESX and ESXi.

Since the Service Console in ESX also includes a firewall that manages both inbound and outbound connections, you'll note that using the vSphere Client to enable NTP this way also automatically enables NTP traffic through the firewall. You can verify this by clicking Security Profile under the Software menu and seeing that NTP Client is listed under Outgoing Connections. In the event that the Service Console firewall did not get automatically reconfigured, you can manually enable NTP traffic.

In ESX, it's also possible to configure NTP from the command line in the Service Console, but this method is more error-prone than using the vSphere Client. There is no equivalent way to configure time with ESXi; you must use the vSphere Client.

Although ESX, ESXi Installable, and ESXi Embedded share the same core hypervisor technology, there are significant differences among the products that may lead organizations to choose one over the other. ESX uses a Linux-based Service Console, for example, while ESXi does not have a Service Console and therefore doesn't have a command-line interface.

Understand VMware ESX/ESXi compatibility requirements.

Unlike traditional operating systems like Windows or Linux, both ESX and ESXi have much stricter hardware compatibility requirements. This helps ensure a stable, well-tested product line that is able to support even the most mission-critical applications.

Plan a VMware ESX!ESXi deployment.

Deploying ESX or ESXi will affect many different areas of your organization-not only the server team but also the networking team, the storage team, and the security team. There are many decisions that must be considered, including server hardware, storage hardware, storage protocols or connection types, network topology, and network connections. Failing to plan properly could result in an unstable and unsupported implementation.

Install VMware ESX and VMware ESXi Installable

ESX and ESXi Installable can be installed onto any supported and compatible hardware platform. Because of the architectural differences between ESX and ESXi, the installation routines are quite different.

Perform post-installation configuration of VMware ESX and VMware ESXi.

Following the installation of ESX/ESXi, there may be some additional configuration steps that are required. If the wrong NIC is assigned to the Service Console/management network, then the server won't be accessible across the network.

Install the vSphere Client.

ESX, ESXi Installable, and ESXi Embedded are all managed using the vSphere Client, a Windows-only application that provides the functionality to manage the virtualization platform. The easiest way to install the vSphere Client is to download it directly from the Web Access page on one of the installed ESX/ESXi hosts.