Power Control Options -- Under Deployment Solution for Dell Servers 3.1 -- Explained

Being able to perform out-of-band remote power control actions on a server can be a necessity in distributed environments. This article will walk you through some of power control's mysteries, such as power control types, how they are used, and a few tricks that can be pulled to make 10G hardware more easily accessible through the DS console.

This feature, called "Power Control" in Deployment Solution for Dell Servers, has long been a lifesaver to IT administrators. Version 3.1, with its support for the new 10G blades, adds some additional features.

Out-of-band management devices come in several flavors:

Before DRAC Vs and iDRAC models came out, BMC and DRAC hardware were separate and operated on different IP addresses. Since then Dell has wisely combined these two pieces of hardware and maintained support for both protocols.

Out of band power control is a feature that must be enabled. This is done via the Configuration Utility available through the DS console under Tools->Dell Tools->Configuration Utility. On the power control tab in this utility there are entries which link machines int he console to their respective out-of-band management device. When an entry exists, power control is "enabled" for that specific machine.

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Entries can be added manually, or they can be discovered. Pressing the "Discover" button allows you to probe a range of IP addresses using the IPMI or DRAC protocol in search of these different types of devices.

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When a discover is complete, entries are added to the list according to the power control type precedence rules. These precedence rules tell the software what to do if there is already an entry for a given server. This is the reason why when adding an entry, the entry might not "stick". For instance, if I had an DRAC entry for my Power Edge 700 that has a DRAC III on IP address 192.168.0.50, then I perform an IPMI discover which discovers a BMC controller on that same server that has the IP address of 192.168.0.51 what would happen? According to the precedence rules that can be viewed by clicking on the "Power Control Options" link at the bottom right of the tab....

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the discover would disregard the IPMI device it just found, and leave the DRAC entry because DRAC (Non-blade) is higher on the list than IPMI (BMC). No machine can have more than one entry in the power control table.

The big question is when we perform a discover we are presented with two options, DRAC and IPMI; but why are we presented with five different options for precedence. These five different options are called "Power Control Types". Let's explain each of these types:

• DRAC (Non-Blade) - Any piece of DRAC hardware as long as it isn't in a blade server (except 10G blades)
• IPMI (BMC) - Any piece of BMC hardware whether in a blade or not.
• 1655 DRAC - A 1655 chassis DRAC that can execute power control commands on each of its blades.
• 1855/1955 DRAC - A 1855/1955 chassis DRAC that can execute power control commands on each of it's blades.
• M1000e CMC - A CMC which is present in all 10G blade chassis'.

So despite only having two protocols (IPMI and DRAC), the way they interact with the hardware underneath is a little more complicated. 1655, 1855 and 1955 Blades are actually controlled through their chassis DRAC's when using the DRAC protocol. This is very important when it comes time to call these utilities to perform an action whether through the console or via a script.

These power control types have another implication; they determine what options are available when you right click a machine. Let's dive into the SQL database to explore this further. Open your SQL database management tool. If you are using Microsoft SQL Server 2005 it is available from the Start menu and is called "SQL Server Management Studio". Then browse into the eXpress database, or the custom name you defined when you installed DS. Next open the dell_power table. Here's a screenshot of an example table:

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Each of these rows represent one entry in the power control tab within the Configuration Utility. If you look at the column labeled "Powerops" you'll see a list of different options separated by | characters. These correspond to the options available when you right click a machine. Each power control type defines a certain set of these options.

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These options can be modified to enable or disable any of the respective power control options available in the console. Before version 3.1, the IPMI power control type did not have the "web" entry which allows the launching of the web interface. This was because most IPMI devices were plain old BMCs which don't support a web console. "Web" was added to 3.1 because of the increasing number of DRAC V and iDRACs which support the IPMI and DRAC protocols on the same IP.

So why is this useful? If you are running 3.0 or 3.0 SP1 of DS for Dell you can add "Web" to your IPMI entries that are for DRACV's or iDRACs. You can also disable certain actions such as a Hard Shutdown, but leave Hard reset enabled you can do so. Additionally you can selectively backup your power control table or use other tools to import lists from an excel spreadsheet into the SQL database.

Lastly, what is the M1000e power control type good for since it doesn't refer to an actual machine? Well, it can be used as an easy way to access the CMC web console through the DS console. Just create a new dummy machine via File->New->Computer from the console and call it "M1000e chassis CMC". Then from within the Configuration Utility, add a manual entry with the machine ID for that dummy machine, and give it the IP address for the CMC. While obviously can't run jobs on a CMC, you can now use it to easily access the web console by right clicking and clicking on "Power Control->Web Interface".

Conclusion

Most of the time all you have to do is hit discover, and give it a range, but knowing what goes on underneath allows you to tweak your environment for those special cases that make things just a little easier.