How does networking inside a virtual machine work?

Your VMware Fusion virtual machines talk to your network using a virtual network adapter. Inside your virtual machine, the guest operating system (Windows, Linux, etc.) believes that it is equipped with an ordinary (wired) Ethernet card. But Fusion patches this card to your Mac’s regular network connection, regardless of whether it is wireless or wired.

What choices do I have for how my virtual machine connects?

Using Fusion’s Virtual Machine menu, you can choose among bridged mode, NAT mode, and host-only mode. NAT mode is the default.

What do these choices mean, and how do I choose the right one for me?

We’ll examine each of these network modes in turn.

What is bridged mode?

Your home or office network is probably equipped with a router for talking to the Internet. Bridging is a network term that describes extending a network without using a router. When you place your virtual machine’s virtual network adapter into bridged mode, your local wired or wireless network is effectively extended to your virtual machine. Your virtual machine becomes a peer of all the other computers on that network.

Although your virtual machine will connect to your local network using the same hardware your Mac uses, the virtual machine will retain its own fully independent network identity. Mac OS’s networking features cannot tell the difference between your virtual machine and a PC on your local network; Mac OS interacts with them over the network in exactly the same way.

Many users’ Macs get their IP address from their wireless base station or router, using a piece of software built into those devices called a DHCP server. In bridged mode, if the operating system inside your virtual machine (Windows, Linux, etc.) is configured to request an IP address from a DHCP server, your virtual machine will get its IP address from the same DHCP server your Mac uses.

What is NAT mode?

NAT is a network technology that protects one network from another. For example, your router probably also acts as a firewall: it protects your Mac by preventing unknown computers on the Internet from connecting directly to it. The term “NAT” is an abbreviation for “Network Address Translation”; the protection afforded by a firewall works (in part) by the router representing your Mac on the Internet. Your router substitutes its own address for your Mac’s.

VMware Fusion’s NAT mode is the same technology, but one layer closer to you. NAT mode protects your virtual machine from the other computers around it by placing the virtual machine on an isolated virtual network. Whenever your virtual machine wants to communicate with your office network or the Internet, it does so through a software firewall. This firewall is a component of VMware Fusion that runs inside Mac OS.

Notice that, in this situation, your virtual machine is not on the same network as your Mac and your router. Compare this to the diagram of bridged mode, in which your virtual machine is a peer of your Mac and your router.

In NAT mode, your virtual machine will get its IP address from a DHCP server supplied by VMware Fusion that runs in Mac OS, just as the firewall does. But this IP address will only be used for relaying communication between your virtual machine and the software firewall; that firewall will represent your virtual machine for its network communication with the outside world. Another way to think about this: from the Internet’s perspective, your virtual machine is sharing your Mac’s IP address.

What is host-only mode?

In host-only mode, your virtual machine is not only protected from your local network and the Internet, but also locked out of them. The virtual machine’s network world is wholly within your Mac.

Just as in NAT mode, your virtual machine will get its IP address from a DHCP server supplied by VMware Fusion that runs in Mac OS.

How do I choose the right network mode for me?

The right network mode for your virtual machine depends on how you plan to use it. In an office or home-office environment, with network printers and file sharing, bridged mode is probably best, particularly because bridged mode allows your virtual machine to use Apple’s Bonjour technology for finding printers. Windows’s workgroup features need bridged mode; only in bridged mode will a Windows virtual machine’s Network Neighborhood show the other PCs on your local network.

NAT mode is ideal when you want your virtual machine to be protected from other computers on your local network, such as when you are using a public wireless connection. Because, in NAT mode, your virtual machine shares your Mac’s IP address for purposes of external communication, it’s especially ideal for use when you are using a paid wireless service, such as in a coffeehouse or hotel. The use of bridged mode would require you to pay twice: once for your Mac and once for your virtual machine.

Host-only mode is useful for environments where your Mac has no network connection at all, or when you wish your virtual machine to be completely isolated from the rest of the Internet.

That’s a lot of choices. How do I keep them all straight in my head?

Here’s a way to think about the network choices:

Can I change from one mode to another?

Yes! But, unless you have configured your virtual machine to use fixed IP addresses, you must tell the operating system inside your virtual machine to release and renew its IP address. Renewing your IP address after you change network modes will automatically contact the correct DHCP server: the one on your local network if you changed to bridged mode, and the one provided by VMware Fusion if you changed to NAT or host-only mode.

To release and renew IP addresses within Windows, open a command prompt using Start -> Run -> cmd . Then, in the command-prompt window, give first this command:

ipconfig/release

then this command:

ipconfig/renew

Rebooting the virtual machine will also cause it to obtain a fresh IP address.

I have been doing an install of SAS 9.2 eBI using Weblogic.

In all the SAS 9.2 install documentation from SAS it mentions Weblogic 9.2, but if you check out:

Oracle WebLogic Server Support for SAS 9.2

You will see Oracle Weblogic 10.3 is supported.  And when you download the install depot from SAS it will actually downloads Weblogic 10.3 in the thirdparty directory for you.

But when you follow the instructions and try and do the install you will probably get an error when the Install Wizard is configuring the web packages.

If you check the install/configure logs you will see this error:

Problem invoking WLST – ava.lang.UnsupportedClassVersionError:
Bad version number in .class file

It seems although the install screen asks you for a location to the 1.5 version of the JDK, you actually need the 1.6 version of the JDK for it to work with Weblogic 10.3, according to this tech support note:

Usage Note 36538: The SAS® Deployment Wizard fails when you use Java Development Kit 1.5 with Oracle WebLogic Server 10.3

So when going through the wizard, point to the JDK 1.6 and you are away.

SAS have issued the 3rd maintenance release to the SAS 9.2 software.

You can find a list of bugs / issues / unplanned features that have been resolved here:

Issues Addressed in SAS 9.2 (TS2M3)

We are doing some work to enable Channels and WRS report scheduling in our SAS 9.1.3 environment.

Its a complete mare!

One of the issues we have struck is the inability to delete any packages you have published to a channel.  They just stay there forever.

In SAS 9.2 you get a utility that lets you delete these packages:

SAS 9.2 Using the Package Clean-Up Utility to Remove Packages

Luckily the friendly chaps at SAS tech Support mentioned that there is a SAS Toolpool entry for 9.1.3 that does teh same function.

So if you need to delete Archived Packages in SAS 9.1.3 channels, then as your friendly SAS dude for the toolpool entry.

Just reviewing my blog Stats on Google Analytics and saw these stats for the last month:

I remember when I started to play around with doing website development over 14 years ago and at the time Netscape had massive market share.  In fact they had so much market share I used to code the sites specifically for Netscape and put some code in to catch all the Internet Explorer users and pass them to a warning page (now wasn’t that customer friendly behavior .

As you can see Netscape isn’t anywhere on the landscape of people who have stumbled across my blog.

Got me to thinking of what other software leaders have disappeared over this time.

Back then I was involved in delivering Accounting Software and was witnessing the death of products such as Chairman and Masterpiece, and the emergence of SAP, Peoplesoft and Oracle.  Interestingly JD Edwards is one of the few that made it through the transition (before they were swallowed by Oracle of course).

Then came the wave of Purchasing software (Ariba etc) and CRM software (Siebel).  Again all gone or swallowed by the big boys.

Next came BI Software, Business Objects, Cognos, Proclarity, Essbase, Hyperion.  Again all swallowed, but the brands survive (for now).

I had already witnessed the rise and fall of Lotus 123 and whatever the word equivalent was (must be getting old can’t remember its name, just remember it had a blue background and white text by default!).

And of course through all this SAS has survived, amazing for a privately owned company, but then again that’s probably the reason it has.

I wonder what the next 10 years will bring?

The place you put your portlet files to automatically deploy them has changed in SAS 9.2.

In SAS 9.1 (windows) you used to place them here:

<sas-install-dir>\Program Files\SAS\Web\Portal2.0.1\DeployedPortlets

In SAS 92 (Windows) you need to place them here:

<sas-config-dir>\Lev1\Web\Applications\SASPortlets4.2\Deployed



When talking to users it was obvious that although we are providing a number of easy to use Web Report Studio reports, as we release more and more data and there applicable reports, easily finding the information they need becomes more and more of an issue.

We typically provide a small number of parameter driven WRS reports.  This reduces our development and maintenance efforts and also allows users to utilise a single report to answer multiple business questions.

In addition each report also has a number of Sections/Tabs (going to miss those when we upgrade to SAS 9.2) that provide different views of the data (i.e by location, by time, by product etc). We do this again to make it easy for users to quickly find the information they need.

But its not till you sit next to a new user that you see how they use (or don’t use) the information we provide.  In our case I see a lot of users struggle to workout which report and which tab they should use to answer their business question.

As a quick workaround we developed a sasInct! portlet that provides a drillable tree of business questions (need to add this to the website) and then used the sasInct WRS linkage tool to automatically open the relevant WRS report, on the relevant section/tab, with the relevant parameters predefined to answer the selected question.

But the next step we wanted to look at was using a Google search  appliance to index all our reports and metadata to take it one step closer.

A quick Google search on Google and SAS (that was weird) found a press release dated 2006 “SAS and Google Partner on BI Search Capabilities“.

Next I found a paper present to SAS Forum in 2007 but no copy of the paper was available so I emailed the author at SAS.

I got a very quick reply from Craig Rubendall @sas with a link to a presentation he co-presented at SAS Forum 2010. (Im always amazed at how accesable and helpful the SAS folk in Cary are, long may it continue)

The paper is at: Integrating the Power of SAS® with the Ease of Search across the Enterprise

He also provided links to download the SAS/Google Search Interface component for both  SAS Content 1.3 (SAS 9.1) and the SAS Content 1.4 (SAS 9.2)

So lots to read and then next step is to talk to our local Google reseller about options and pricing.  Ill post what I find out.

And of course if anybody has been through this already, feel free to get in touch, cause no doubt there will be some tricks for new players

Wendy gave me a tip off that Paul Holmes now has a blog over at Platformadmin.com, check it out.

It also looks like Paul has his SAS Metadata Security plugins up and for sale at Metacoda.com.

One of the best SAS BI Developers I know is looking for some extra work.

They would like 20 hours a week and are based in New Zealand, so will suit a customer who is happy to have development work done via remote login.

They are experts in:

• SAS Web Report Studio 3.1
• Information Map Studio 3.1
• EG 4.1

Benefits of using somebody remotely in New Zealand:

• They can work when you are asleep
• The exchange rate is in your favour 1 : 0.75 for the USD (save 25%), 1 : 0.5 to the Pound (save 50%)
• The are used to working fast and accurately

So if you are looking for some extra resource Contact Me

I am doing some work around using SAS OLAP Server in ROLAP mode in SAS 9.1.3 at the moment.

We have all our Warehouse reporting data stored in Star Schema’s in an Oracle Database.

We have found that the users are accessing the Information Maps we have created via SAS AMO, which is a good thing.

But the bad thing is that when a user outs that data into a pivot table, Excel/AMO downloads the data and stores it in Excel to populate the pivot table ans they are ending up with some massive Excel file sizes.

The answer is to build some OLAP Cubes and use these as the source for the pivot table.  But of course then we strike the issues with OLAP in SAS 9.1.3 such as no incremental updates, OLAP locking etc.

So we are trialing SAS OLAP Cubes in ROLAP mode whihc means the data is retained in Oracle and only the cube structure is built in SAS, which bypasses all these issues.

But of course it is not as easy as it seems.  We run a distributed SAS Windows environment so I need the OLAP server to be able to see the oracle instance etc.

In testing I found it a pain to have to login to Excel/AMO and/or EG to test the OLAP Cube.  Also if there are any errors not a lot of detail is provide.

So instead I just use this code:

proc sql;
connect to olap (host=<host> port=5451 user=<user> pass=,pwd>);
select * from connection to olap (
SELECT
{ [Measures].[COUNTSUM] } ON COLUMNS  ,
{ [region].[region].DefaultMember.Level.Members } ON ROWS
FROM
[,olap_cube_name.]
);
disconnect from olap;
quit;

Check the logs and see any errors.