Archive for January 2012

Network Time Sync for VMware ESXi Hosts

January 28, 2012 Time Syncing, VMware No comments

In a virtual infrastructure, network time synchronization is critical to keep servers on the same schedule as the services they rely on. For VMware ESXi hosts, you can implement Network Time Protocol (NTP) synchronization using the vSphere Client.

More on VMware networking

There are many reasons you should synchronize time for ESXi hosts. If they are integrated with Active Directory, for instance, you need time to be properly synchronized. You also need the time to be consistent when creating and resuming snapshots, because snapshots take point-in-time images of the server state. Luckily, setting up network time synchronization with the vSphere Client is pretty easy.

VMware network time synchronization: A walkthrough

To configure NTP synchronization, select the host, and on the Configuration tab, select Time Configuration under Software. You’ll now see the existing time synchronization status on that host. Next, click Properties. This selection shows the Time Configuration screen, where you can see the current time on the host. Make sure it’s not too different from the actual time, because a host that’s more than 1,000 seconds is considered “insane” and won’t synchronize.

After you set the local time on the host, select NTP Client Enabled. This activates NTP time synchronization for your host. Reboot the server, then go to Options to make sure NTP has been enabled. This gives you access to the NTP Startup Policy, where you should select “Start and stop with host.”

You’re not done with network time synchronization yet, though. Now, you need to choose NTP servers that your VMware ESXi hosts should synchronize with. Click NTP Settings and you’ll see the current list of NTP servers. By default, it’s empty. Click Add to add the name or address of the NTP server you’d like to use. The interface prompts you for an address, but you can enter a name that can be resolved by DNS as well.

If you’re not sure which NTP server to use for VMware network time synchronization, the Internet NTP servers in pool.ntp.org work well. You only need to choose one server from this group to add to the NTP servers list. If you want to synchronize with an internal or proprietary NTP server, however, you should specify at least two NTP servers.

At this point, make sure the option to restart the NTP server is selected. Click OK three times to save and apply your changes. From the Configuration screen on your ESXi host, you should now see that the NTP Client is running, and it will also show the list of current NTP servers your host is using.

With your ESXi hosts synchronized to the correct time, all the services and events that depend on time will function properly. More importantly, you won’t waste any more time because of misconfigured network time

Whats the diffference between VMware vCLI and VMware PowerCLI

January 28, 2012 Command Line, IT No comments

To automate the management of an ESXi deployment, VMware has created easy-to-use scripting tools for managing day-to-day operations. You can write scripts with the same functionality as the vSphere client to automate manual tasks , allowing you to manage small- to large-scale environments efficiently. These tools work well with both ESXi and ESX hosts, allowing you to easily administer mixed environments.

Both PowerCLI and vCLI are built on the same interface as the vSphere Client. They can be pointed directly at an ESXi host or they can be pointed at vCenter. When pointed at a host, they can execute commands directly on an ESXi host, similar to how a command in the Console OS of ESX operates on only that host. Local authentication is required in this case. Alternatively, when communicating through vCenter, the vCLI and PowerCLI commands benefit from the same authentication (e.g. Active Directory), roles and privileges, and event logging as vSphere Client interactions. This provides for a much more secure and audit-able management framework

VMware vSphere™ PowerCLI

VMware vSphere PowerCLI is a powerful command line tool for automating all aspects of vSphere management, including host, network, storage, VM, guest OS and more. PowerCLI is distributed as a Windows PowerShell snapin, and includes more than 150 PowerShell cmdlets, along with documentation and samples. PowerCLI seamlessly blends the vSphere platform with Windows and .NET, which means you can use PowerCLI by itself or within many different 3rd-party tools

VMware vSphere™ Command Line Interface (vCLI)

VMware vSphere™ Command Line Interface (vCLI) is a set of command-line utilities that help you provision, configure and maintain your ESX and ESXi hosts. The vCLI command set allows you to run common system administration commands against VMware ESXi systems from any machine with network access to those systems. You can run most vCLI commands against a vCenter Server system and target any ESXi system that the vCenter Server system manages. There are commands that can completely automate the initial configuration of an ESXi host and others that provide troubleshooting and diagnostic capabilities. VMware provides vCLI packages for installation on both Windows and Linux systems

VMware vSphere™ Management Assistant (vMA)

The VMware vSphere™ Management Assistant (vMA) is a virtual appliance that brings together all the tools you need to manage vSphere. vMA packages the vSphere Command Line Interface, the vSphere SDK for Perl, as well as logging and authentication modules into one convenient bundle. vMA can also host 3rd-party agents for added management power.