“Going Green” is “all the rage”. Likely, you have seen the IBM commercials where the birds and squirrels come out and the screen turns green when the company chooses to “go green”. Because of this, “going green” has become a cliché. However, the practical applications of this make complete sense. By using virtualization and energy saving features like DPM, you can save as much as 40% in electricity costs as well as all the other benefits of using virtualization.
VMware’s Distributed Power Manager (DPM) is part of VMware’s Distributed Resource Scheduler (DRS). Just as DRS works to optimize the resource load across multiple ESX host servers, DPM can fit into that by migrating VM guests off of servers that are not in use and shut the host system down. Even better, once you configure DRS, using DPM is virtually a “checkbox away”.
Here is how VMware describes DPM-
“VMware DRS includes experimental distributed power management (DPM) capabilities. When DPM is enabled, the system compares cluster- and host-level capacity to the demands of virtual machines running in the cluster. Based on the results of the comparison, DPM recommends (or automatically implements) actions that can reduce the power consumption of the cluster.”
Why have servers powered on that are not needed and are not in use? This is like leaving the light on in your office when you go home for the day – a waste of electricity and of your company’s money. DRS is able to automatically power off the servers that are not needed.
Let’s find out how to configure DPM.
How do you configure VMware Distributed Power Management (DPM)?
Before I show you how to configure it, let me start with a few requirements that you nee to make sure you meet.
VMware Virtual Infrastructure Suite Enterprise (or it can be purchased separately)
Two or more ESX host servers installed and running
Wake on LAN (WOL) available and enabled on the ESX host servers
VMware Virtual Center managing those host servers
If you are unsure if your physical server (ESX host system) supports WOL, you can bring up the server inside the VI Client, go to the Configuration Tab, then click on Network Adaptors, and you will see the Wake on LAN Supported column, as in the graphic below.
Figure 1: Checking to see if your adaptor supports WOL
Note that you may also need to go into your server’s BIOS and ensure that Wake on LAN is enabled there as well.
Next, go into your VI Client Configuration -> Networking section and make sure that the adaptor associated with the server’s VMkernel vSwitch is also an adaptor that supports WOL. If this is not the case, you will need to do some adaptor rearranging because DPM uses the server’s VMkernel vSwitch NIC.
Figure 2: Checking to see if your VMkernel adaptor is connected to the physical WOL adaptor
You can test WOL easily using VMware ESX and the VI Client. To do this, VMotion off production VMs from an ESX host, put that ESX host in standby mode. Next, wake it up by using Power On, in the VI Client, for that host.
Next, you need to create a typical ESX Server Cluster by right clicking on the datacenter, then clicking New Cluster.
Figure 3: Creating a DRS cluster
From there, you will go through the new cluster wizard. It is critical that you choose for this ESX host cluster to be a Distributed Resource Cluster, like this:
Figure 4: Creating a DRS enabled Cluster
You could, of course, also make it a HA cluster.
Go though all the typical DRS cluster setup configuration, review your configuration in the final step, and click Finish to create your DRS (soon to be DPM) cluster.
Now that you have your cluster, right click on the cluster and click Edit Settings, as you see in Figure 5.
Figure 5: Editing settings on a VMware DRS Cluster
Inside the cluster settings window, under VMware DRS, you can click on Power Management, as you see in Figure 6.
Figure 6: Power Management options for the DRS Cluster
With the cluster power management options, you can choose to either 1) turn off DPM for the cluster, 2) set the cluster to manual DPM or, 3) set the cluster to fully automatic DPM. You can also manually override the DPM settings for each ESX host that is in that cluster in the Host Overrides section of the Power Management window (see Figure 6).
Let’s talk about manual versus automatic for a moment. With a manual DPM cluster, DPM will make recommendations to power on or off servers in your cluster based on the demand. You can see one of these recommendations in Figure 7 and close up of the recommendation in Figure 8.
Figure 7: DPM Recommendation for a manual DPM cluster
Figure 8: DPM Recommendation for a manual DPM cluster
In Figure 7, you can see how you can choose to Apply Recommendation and accept this power off.
On the other hand, with an automatic DPM cluster, the guests are automatically migrated off of a host that is not needed and that host is automatically powered off. There will not be any questions, you will just see in the Events section of your VI Client that VM guests have been migrated and that hosts are “Entering Standby Mode”. An example of this is in Figure 9.
Figure 9: ESX Host in a DPM cluster is entering Standby Mode due to Automatic DPM
You can tell the status of your DRS/DPM cluster by looking at the Summary tab of the cluster, as you see in Figure 10.
Figure 10: Summary tab of a DRS/DPM Cluster in Automatic mode
Honestly, I recommend the automatic mode but you should test it in manual mode first.
Isn’t DPM Experimental?
Yes, DPM is still considered an experimental feature. When you first enable DPM, you will see the following warning, in Figure 11.
Figure 11: Warning about DPM being experimental
Still, I hope that you will not let that deter you from using DPM in test, then in production once you are confident about DPM. Actually, many of VMware’s most successful and helpful features are still considered “Experimental”.
Can I see VMware DPM in Action?
Whether you are using VMware DPM or just thinking about it, I recommend everyone to take a look at this YouTube video demonstrating VMware DPM in action. The proof of the power of DPM is in the video!
In this article, I covered how to configure VMware Distributed Power Management (DPM), step by step. Part of VMware’s distributed resource scheduler (DRS), DPM is used to migrate VM guests off of servers that aren’t in use and shut the host system down. This can save a tremendous amount of data center resources – both in power and cooling!
And finally, I would like to give credit to Eric Siebert of TechTarget’s Virtualization Pro blog for his post on how to configure VMware DPM. You can find it at: Configuring Distributed Power Management. His quick, step by step, approach served as a great model for this article.