Thanks again to Ed Haletky (@Texiwill) for coming along and presenting this week. Here is the video from the session:

BrownBag #10 – Security Deep Dive from ProfessionalVMware on Vimeo.

Links:

• Virtualization Practice – Ed’s Blog
• http://www.virtualizationpractice.com/blog/?file_id=41 – Resources!
• Virtualization Security Roundtable

The following is a guide on how to get Oracle 10g R2 RAC installed on ESX 3.5 using CentOS Virtual Machines. Quite a mouthful, isn’t it? This was written up by Justin Mungal. In the guide Justin covers every thing needed to get Oracle RAC installed on ESX 3.5 and then some. It should be noted that this is not for production, nor is it supported. However, it will give you a good handle on getting your lab up and running.

Here are the topics:

• Pre-requisites
• Hypervisor Configuration and VM Creation
• CentOS 5.4 installation
• Virtual Machine Storage Configuration
• Clusterware and RAC pre-installation procedures
• Installing Oracle Clusterware
• Installing Oracle 10g R2 Database
• Creating a database with DBCA
• RAC Verification

The guide itself is entirely too long (but very very detailed) to copy here, and so it can be found here.

About The Author

Justin Mungal has been working in IT for about 8 years. He’s a former SQL Server DBA with a background in System’s Administration. He’s currently employed as an Oracle DBA at a technology company in San Antonio, Texas.

@vRobM and I were discussing an unrelated topic when DRS and the mysterious stars came up.  (**)?  Our first instinct was this was the “special sauce” between the two all beef patties.  However after some creative KB searching we came across a formula that describes it quite well:

DRS Recommendations

To understand the stars, you need to understand where to find them and what they mean. The following is taken from the VI3 docs:

Priority for this recommendation, as a number of stars.  Five stars, the maximum, indicate a mandatory move because of a host entering maintenance mode or affinity rule violations. Other ratings denote how much the recommendation would improve the cluster’s performance; from four stars (significant improvement) to one star (slight).

So that explains what the stars indicate as far as recommendations go.  But what makes a 3 star and what makes a 4 star recommendation?

Calculating the Priority

Turns out that this isn’t exactly the special sauce we thought it was. Rather, there is some carefully reasoned out math that goes into this.  This KB article spells it out in detail, but we’ll hit the high points.  First the formula:

6 – ceil(LoadImbalanceMetric / 0.1 * sqrt(NumberOfHostsInCluster)).

There are two variables in there and only one of which is obvious, “LoadImbalanceMetric” however can be interesting:

LoadImbalanceMetric is the current host load standard deviation shown on the cluster’s Summary page of the vSphere Client.
For each host, compute the load on the host as sum(expected VM loads)) / (capacity of host). Then compute the standard deviation of the host load metric across all hosts to determine LoadImbalanceMetric.

So where does one find this standard deviation? Select your cluster, then summary and look for the following section:

In our particular case, not much to look at, as well, she is seemingly a well balanced cluster. However let’s work through the formula with the assumption that we have a 2 node cluster and a standard deviation of 0.282 (the “target” from above):

6 – ceil(0.282 / 0.1 * sqrt(2)).

What is Ceilias brother Ceil doing with my numbers?

Turns out, it is not a family of mathematicians busily flicking their abacus’.  ‘Ceil’ here, represents the Ceiling function, which I’m sure you’ve heard of before.

According to Wikipedia the Ceiling function is:

In mathematics and computer science, the floor and ceiling functions map a real number to the largest previous or the smallest following integer, respectively. More precisely, floor(x) = ⌊x⌋ is the largest integer not greater than x and ceiling(x) = ⌈x⌉ is the smallest integer not less than x.

So that works out as:

or:

6 – the smallest number not less than (0.282 / .1 * sqrt(2)) which equals 2, hence, a 2 star recommendation. (**)!

More info: Duncan Epping @ Yellow-Bricks has put together an excellent Deep-dive page for DRS, where you can get into much greater detail.

WolframAlpha to the Rescue

While this can easily be done in any random calculator (or in the heads of some folk) I used WolframAlpha to good avail.  It’s quick and gives you a graphical breakdown of the formula. Just plug in new values and go!

Summary

The recommendations and mathematical bits take place behind the scenes seamlessly.  After all, that is the magic of DRS.  However, it helps to have an understanding of the actual logic and math that goes into those recommendations so you can better understand your cluster, and better plan for new hosts and workloads.  As always drop a line in the comments or tweet to either @vRobM or myself on Twitter.

Update: Thanks for the excellent deep-dive page Duncan!

I mean it. Really. One of my pet peeves is the fellow who installs VMware server on his workstation to run his work provided Windows XP image (or some variant of Linux). The logic behind this usually goes something like:

“I needed to be able to create virtual machines and VMware Server is the only free VMware product that will let me do that.”

First, while that may have been the case in the past, it is not anymore. Second, there are a host of reasons why Server likely is not suited for your workstation workloads.

When to use VMware Server (Use Case pt 1)

I hear you asking: “Well, when do I use VMware Server?”. The answer here is that server has a few use cases. For example, if your server hardware is not otherwise on the HCL and you have a need to run VMs in a non production environment. Server makes a great choice. It also makes a great choice when you want the virtual machines to start on boot, and will be accessing them remotely. It also makes sense when doing server development and snapshots are critical.

When not to use VMware Server (Use Case pt 2)

This list may actually be a bit longer than the above. Basically, you will want to avoid VMware server if you will be:

• Managing VMs from the console
• Want to play Doom or use 3d acceleration (can be enabled in the vmx, but let’s not go there)
• Need workstation like performance
• Continued upgrades and support (http://virtualization.info/en/news/2010/05/vmware-server-to-be-discontinued-by-june-2011.html)

Basically, VMware Server is well suited for background server work loads, rather than in your face workstation like work loads. You have VMware Player for that.

Alternatives

So if you’re not supposed to use VMware Server for workstation tasks… what are you to use? In keeping with the “Free” product type requirement, there are several good alternatives:

• VMware Player 3.0
  Player 3.0 gives you the ability to create and run virtual machines and seemingly shares some of it’s code base with VMware Workstation. Meaning while they may not be feature compatible, you will still be performance compatible.
• Sun/Oracle Virtual Box
  A bit more feature rich (teleportation anyone?). Virtual box is open source and free for use as well. It also provides excellent workstation performance.

Some for-cost alternatives involve VMware Workstation or Fusion, as well as Parallels. I’d be amiss if I didn’t also tell you that if your hardware is on the HCL and you don’t mind remote access, ESXi is likely the route to go with your server workload issues.

Summary

Basically, you’ll want to use VMware Server for server workloads on hardware that is not otherwise on the VMware HCL. For everything else there is ESXi or VMware Player (or Virtualbox, etc).

This weeks call with Jon Hall was full of interesting folks and even more interesting information about the VMware certification tracks. Note: Due to the content of the video VMware kindly requested I remove it until they make their official announcements in the not too distant future.

I want to thank again everyone for coming and making it an interesting call. Please drop a line in the comments if you have any questions or suggestions for the next one.

Being that I will have quite a bit of downtime in the near future (a broken arm will do that). Here is what is currently on my reading list:

• Tribes – Seth Godin
  Not exactly virtualization, but as a blogger it applies. In sum: “Stop waiting, start doing.”
• Presentation Zen – Garr Reynolds
  Again, not 100% virtualization focused, but the techniques / thoughts apply to both Virt & blogging. In sum: “What are you trying to do (explain, show, architect), and why is it important) See also Patrick Ancillotti’s vZen post.
• vSphere 4 Administration Instant Reference – Scott Lowe, Jason McCarty, Matt Johnson
  As with Scott’s blog, and other vSphere tome, I have high expectations for this one. Already almost two chapters in, and it has yet to disappoint.
• vSphere 4 Implementation – Mike Laverick
  I’ve loved reading Mike’s blog, and more recently his SRM books. Being an instructor, he packages his writing so the end user understands the topic at hand.

Like the last several posts, this one hails from the storage section of the Enterprise Admin Blueprint. The Enterprise Admin exam is one of the several requirements to becoming a VCDX. As I go down this path, I hope to share with you some of my exam prep in the hope that it will help you as well.

Seems this is becoming part of a series. Like the last few posts, this one was also produced from objective 1.1 of the VCDX Blueprint, and is part of my exam prep.

Task:

esxcfg-module – Unload/Load modules & check module status.

The Command:

[root@ProfessionalVMware root]# esxcfg-module
Usage: esxcfg-module <options> <module>
   -g|–get-options   Get the options for a given module and whether it is loaded on boot.
   -s|–set-options   Set the options for a given module.
                      WARNING this may be overwritten by per device options.
   -e|–enable        Enable a given module, indicating it should be loaded on boot.
   -d|–disable       Disable a given module, indicating it should not be loaded on boot.
   -q|–query         Query enabled modules options.
   -l|–list          List all modules and whether they are enabled.
   -h|–help          Show this message.

In this case I’ve only included the relevant output.

Checking Module Status:

[root@ProfessionalVMware root]# esxcfg-module -l
Device Driver Modules
Module         Enabled Loaded 
vmklinux       true    true   
mptscsi_2xx    true    true   
e1000          true    true   
lvmdriver      true    true   
vmfs3          true    true   
etherswitch    true    true   
shaper         true    true   
tcpip          true    true   
cosShadow      true    true   
migration      true    true   
nfsclient      true    true   
deltadisk      true    true   
vmfs2          true    true   

Loading/Unloading:

[root@ProfessionalVMware root]# esxcfg-module –disable vmfs2
[root@ProfessionalVMware root]# esxcfg-module –list
Device Driver Modules
Module         Enabled Loaded 
vmklinux       true    true   
mptscsi_2xx    true    true   
e1000          true    true   
lvmdriver      true    true   
vmfs3          true    true   
etherswitch    true    true   
shaper         true    true   
tcpip          true    true   
cosShadow      true    true   
migration      true    true   
nfsclient      true    true   
deltadisk      true    true   
vmfs2          false   true   
[root@ProfessionalVMware root]# esxcfg-module –enable vmfs2
[root@ProfessionalVMware root]# esxcfg-module –list
Device Driver Modules
Module         Enabled Loaded 
vmklinux       true    true   
mptscsi_2xx    true    true   
e1000          true    true   
lvmdriver      true    true   
vmfs3          true    true   
etherswitch    true    true   
shaper         true    true   
tcpip          true    true   
cosShadow      true    true   
migration      true    true   
nfsclient      true    true   
deltadisk      true    true   
vmfs2          true    true   

Thanks for tuning in.

Like the last post, this one also hails from objective 1.1 of the VCDX Blueprint, and is part of my exam prep.

Task:

Configure an NFS Datastore using command line tools.

Solution:

[root@ProfessionalVMware root]# esxcfg-nas
esxcfg-nas <options> [<label>]
-a|–add                Add a new NASc filesystem to /vmfs volumes. 
                        Requires –host and –share options.
                        Use –readonly option only for readonly access.
-o|–host <host>        Set the host name or ip address for a NAS mount.
-s|–share <share>      Set the name of the NAS share on the remote system.
-y|–readonly           Add the new NAS filesystem with readonly access.
-d|–delete             Unmount and delete a filesystem.
-l|–list               List the currently mounted NAS file systems.
-r|–restore            Restore all NAS mounts from the configuration file.
                        (FOR INTERNAL USE ONLY).
-h|–help               Show this message.

More specifically:

[root@ProfessionalVMware root]# esxcfg-nas –add –host 192.168.15.252 –share /storage/iso ISO
Connecting to NAS volume: ISO
ISO created and connected.

Result:

[root@ProfessionalVMware root]# esxcfg-nas –list
ISO is /storage/iso from 192.168.15.252 mounted

While the content may seem obvious to some, this post is here to help those that still have their exams to prep for, or find themselves wandering about aimlessly on the CLI trying to configure NFS. Thanks for tuning in.

This one is taken from the first objective in the VMware Enterprise Admin Exam Blueprint. Specifically from the skills section:

- Perform advanced multi-pathing configuration
– Configure multi-pathing policy
— Configure round-robin behavior using command-line tools

After logging into the host via SSH, and getting to root, this can be done with the “esxcfg-mpath” command. Let’s take a look at this command:

[root@ProfessionalVMware root]# esxcfg-mpath
esxcfg-mpath <options> [--lun=<LUN>] [--path=<path>]
-l|–list                     List all LUNs and their paths.
-p|–policy <type>            Set the policy for a specific LUN.  Requires
                              a –lun flag.  Type must be one of mru, rr, fixed or custom.
-H|–custom-hba-policy        Set the custom HBA policy value.  Must be one of
                              mru, preferred, any, minq.
-T|–custom-target-policy     Set the custom target policy value. Must be one of
                              mru, preferred, any
-C|–custom-max-commands      Set the custom policy value for max commands
-B|–custom-max-blocks        Set the custom policy value for max blocks
-s|–state <on|off>           Set the state for a specific LUN Path.  Requires
                              both –lun and –path flags.
-f|–preferred                Set the given path to be preferred for the
                              given LUN.  Requires both –path and –lun flags.
-q|–query                    Query the information on a specific LUN. 
                              Requires a –lun flag.
-P|–path=vmhbaX:X:X          Used to specify a path for setting the
                              path state or preferred path.  Uses the
                              VMkernel internal path name.
-L|–lun=vmhbaX:X:X           Indicate which LUN to operate on.  This can be
                              either the internal VMkernel vmhba name for
                              this LUN (vmhbaX:X:X) or the vml name as
                              found in /vmfs/devices/disks.
-v|–verbose                  Show all information about the LUNs and
                              paths, otherwise a minimal set of data
                              is displayed to conserve space.
-b|–bulk                     Bulk path listing suitable for parsing.
-a|–hbas                     List HBAs on the system with a unique ID
                              if one is available.
-h|–help                     Show this message.
-r|–restore                  Restore path setting to configured values
                              on system start. (INTERNAL USE ONLY)

Quite the command, isn’t it? And that is but half the output. The particular switches we are interested in are –p or –policy to which we’ll feed the “rr” or round robin switch. We’ll follow that up with the –L or –lun to specify which lun we’re operating on. Here’s an example:

[root@ProfessionalVMware root]# esxcfg-vmhbadevs
vmhba0:0:0     /dev/sda                       
[root@ProfessionalVMware root]# esxcfg-mpath –policy=rr –lun=vmhba0:0:0
Setting vmhba0:0:0 policy to rr

In all practical terms, on my lab box that didn’t accomplish much, as there is only one actual path to the disk, however, we can still see the changes in the VI Client:

Note: esxcfg-mpath is not actually listed in the tools section for this objective, but is indeed the way to accomplish this.

While this actually requires no special settings, I figure it’s worth noting, if for nothing more than to state that in VMware Fusion 3, ESX 3.5 requires no additional settings to be operational. Basically it works as follows:

1. Download the ESX ISO (vmware.com/download/vi)
2. In VMware Fusion create a new virtual machine, choosing said ISO:
   
3. The correct OS is installed automatically. The version may be ‘incorrect’ but it works just fine:
    
4. And all installed:
   

Also of note: The splash screen seemingly does a lookup against the hostname you have configured to produce the IP address displayed.