How about this?

I have seen this on a couple of occasions how one or more compute nodes in an ExaLogic rack has a different time than the others. Their clocks are simply not in sync. This is not good as a lot of things depends on computers being in sync with each other. This is not anything specific to ExaLogic. It just so happen that I've seen it there recently. I have not been able to get to the root cause in these occasions. The reason for that has been that the NTP server was outside my reach and control. My guess is that in both these occasions it was due to a network issue. The workaround decribed below solved the issue both times though.

Edit the NTP daemon file (as root)

#vi /etc/sysconfig/ntpd 

(or use the more modern nano editor)

Look for the OPTIONS section near the top of the file

OPTIONS="-u ntp:ntp -p /var/run/ntpd.pid"

Add the -x parameter which will force a sync every time the ntpd service is restarted

OPTION="-x -u ntp:ntp -p /var/run/ntpd.pid"

Restart the ntpd service

#service ntpd restart

Please note that this is just a work around as the real issue (likely network related) is not addressed. The cost of forcing a resync every time the service is restarted i negligible. So I see no problem with leaving the -x flag in there.

A more permanent solution for the rack could be to configure an NTP source in the rack. That will eliminate outside network dependencies but could of course also introduce sync issues with the rest of your network.

Setup NIS Client(s)

For each Compute Node/Host that needs to Authenticate via NIS perform the following steps from the Master section above

1. Install ypserv 2. Define Domain Name and Servers servicing the domain 3. Define NIS Domain for the compute node 5. Define how lookups reference NIS 8. Restart rpcidmapd service

Next:

Configure services for auto start on boot

At the command prompt enter:

chkconfig portmap on chkconfig rpcidmapd on chkconfig yppasswdd on chkconfig ypxfrd on chkconfig ypbind on

Start All NIS Services

At the command prompt enter:

service portmap restart service rpcidmapd restart service yppasswdd start service ypxfrd start service ypbind start

Creating and Managing Users

With NIS now configured you will manage users and groups as you did before but it will all have to be done on the Master and as shown above and pushed to the Slaves with the make command.

Changing Passwords

NIS Slave Server(s) Setup

Follow the same steps as for the Master setup above except for step 10 (Initialize NIS map) that is a little different on the Slave(s).

Initialize NIS map for Slave from Master

If hostname does not resolve to the IP address you want the ypserver to run on then you need to temporarily redefine hostname to a value that resolves to the desired IP. On compute nodes the hostname typically resolves to the Management IP (1 GB) interface. By setting hostname to the private IB hostname one could use ypserver on that network instead.

Change hostname at command prompt:hostname <name of host>Example:

hostname nis2.us.oracle.com

To initialize slave for use of maps from master, enter at command prompt /usr/lib64/yp/ypinit -s <master server name>

  Example:

/usr/lib64/yp/ypinit -s nis1.us.oracle.com We will need a few minutes to copy the data from nis1.us.oracle.com.

Transferring passwd.byuid... Trying ypxfrd ... success Transferring netid.byname... Trying ypxfrd ... success Transferring services.byservicename... Trying ypxfrd ... success Transferring group.byname... Trying ypxfrd ... success Transferring passwd.byname... Trying ypxfrd ... success Transferring protocols.byname... Trying ypxfrd ... success Transferring rpc.bynumber... Trying ypxfrd ... success Transferring group.bygid... Trying ypxfrd ... success Transferring ypservers... Trying ypxfrd ... success Transferring hosts.byaddr... Trying ypxfrd ... success Transferring mail.aliases... Trying ypxfrd ... success Transferring protocols.bynumber... Trying ypxfrd ... success Transferring hosts.byname... Trying ypxfrd ... success Transferring services.byname... Trying ypxfrd ... success Transferring rpc.byname... Trying ypxfrd ... success

  nis2.us.oracle.com's NIS data base has been set up. If there were warnings, please figure out what went wrong, and fix it.

At this point, make sure that /etc/passwd and /etc/group have been edited so that when the NIS is activated, the databases you have just created will be used, instead of the /etc ASCII files.

Start All NIS Services

At the command prompt enter

service portmap restart service rpcidmapd restart service ypserv start service ypbind start service yppasswdd startservice ypxfrd start

Synchronize Maps from Master

When you have a NIS Master and one or more Slaves (and you should) they need to be in sync. The best scenario and the default one is for the Master to push it's changes to the slaves as they happen.

Make this happen by editing NIS master Makefile to allow database push to slaves:

In /var/yp/Makefile set the following:

NOPUSH=false

As users and groups will be managed from the master server changes will now be pushed when you rebuild the NIS map database. This is done with a make command

make -C /var/yp

The second option is to initiate a pull from each Slave. This can be used for instance when Master and Slaves are not in the same subnet.

On the slave server one would then need to create a simple script to ‘fetch’ updated maps from the master. This script can then be executed on demand as needed or scheduled to run as a cron job periodically depending on your implementation requirements.

Example: Create a script called doXfr in /var/yp on the slave node.

This file would contain (ypxfr line is a single line)

#!/bin/sh /usr/lib64/yp/ypxfr -h vboxcn01-priv.corning.com -d corning.com group.bygid hosts.byaddr mail.aliases passwd.byname protocols.byname rpc.byname services.byname ypservers group.byname hosts.byname netid.byname passwd.byuid protocols.bynumber rpc.bynumber services.byservicename

NIS Master Setup and Required software

We are now ready to get started with the actual configuration of NIS in our little Data Center. The config files involved for a NIS Master setup is:

/etc/yp.conf/etc/sysconfig/network /etc/ypserv.conf /etc/nsswitch.conf /etc/idmapd.conf /var/yp/securenets /etc/hosts.allow /var/yp/ypservers (will be created and populated by ypinit)

Lets start…. 

1. Install ypserv

Check if ypserv is installed in all machines using NIS.

rpm -q ypserv

If it is not installed use yum install ypserv to install it, or use the rpm to install it directly. You don’t have yum configured you can just go to public-yum.oracle.com, It has all the details and it’s just one command to run as root.

You also need nfs-utils and yp-tools but they would typically already be there. If not install with:

yum install nfs-utilsyum install yp-tools

2. Define Domain Name and Servers servicing the domain

NIS needs a NIS domain name to service. This domain name is used when a client broadcasts it’s request for info. You can view NISDOMAIN and domainname as simple group names used for NIS members. It is not recommended that you use the network/dns (us.oracle.com in my example here) domain name defined for the compute nodes as NISDOMAIN.

NISDOMAIN and domainname only referes to NIS/YP configurations. It has nothing to do with the computers real dns domain. This is true for linux and the recommendation is to NOT set them to be the same as the dns domain as it can make debugging more complicated.

However, for Solaris I’m told that NISDOMAIN & domainname must be set to be the same as the DNS domain of the computer.

Edit /etc/yp.conf to add the name of the NIS domain and the NIS servers (master and slaves). Additionally you can define the IP/hostname to use for the ypserver process, by default ypserver will bind to IP that hostname resolves to. If you define the ypserver, note that the slave server(s) should use the slave server IP/hostname for ypserver (it should point to itself).

Example (this shows the NIS Master):

domain us.oracle.com server nis1.us.oracle.com domain us.oracle.com server nis2.us.oracle.com

3. Define NIS Domain for the compute node

Edit /etc/sysconfig/network to define the NIS Domain that will be used by the compute node.

Example:

NETWORKING=yes NETWORKING_IPV6=no HOSTNAME=nis1 NISDOMAIN=us.oracle.com domainname=us.oracle.com

This definition ensures that the NISDOMAIN and domainname is set when the server starts.

The only time the NIS domain is set is if you have ypbind enabled (e.g.”chkconfig ypbind on” & “service ypbind start”). The ypbind script will scan /etc/sysconfig/network, /etc/sysconfig/ypbind or /etc/yp.conf so you can put the NISDOMAIN definition in any of those files.

4. Validate configuration for ypserv

Edit /etc/ypserv.conf to ensure the following entries exist.(File normally exists with the specified entries defined by default. However, it is possible that it may not have these entries until the service is started)

dns: nofiles: 30 xfr_check_port: yes * : * : shadow.byname : port * : * : passwd.adjunct.byname : port

5. Define how lookups reference NIS

Edit /etc/nsswitch.conf

You will likely need to add the sections identified in bold (they are not located together in the file)

passwd: files nis shadow: files nis group: files nis automount: files nis nisplus aliases: files nis nisplus

6. Limit Access to specific subnets

This configuration authorizes only a single subnet to authenticate with the NIS server. It is optional but strengthens the security of NIS.

Create /var/yp/securenets Add the following lines:

host 127.0.0.1  255.255.255.0 192.168.24.0

You can also specifically list the hosts (instead of the subnet range as shown above) allowed to authenticate with NIS.

7. Specify Hosts allowed to access NIS maps

Edit /etc/hosts.allow to specify IP addresses allowed. Example:

# hosts.allow This file describes the names of the hosts which are # allowed to use the local INET services, as decided # by the ‘/usr/sbin/tcpd’ server. #

portmap : 127. : allow portmap : 192.168.24. : allow portmap : ALL : deny

Here again, the IPs specified would be specific to your deployment. Purpose of the above setting is to force the NIS lookup to only use the specified network. This becomes more important when we look at ExaLogic where you have several networks in the rack.

8. Restart rpcidmapd service

Prior to starting the rpcidmapd service, edit /etc/idmapd.conf to define the domain name.

Example:

[General] Verbosity = 0 Pipefs-Directory = /var/lib/nfs/rpc_pipefs Domain = us.oracle.com

[Mapping]

Nobody-User = nobody Nobody-Group = nobody

[Translation] Method = nsswitch

To restart the service, type at the command prompt

service rpcidmapd restart

Example output:

Stopping RPC idmapd: [ OK ] Starting RPC idmapd: [ OK ]

9. Configure services to auto start on boot

At the command prompt enter:

service portmap start chkconfig portmap on chkconfig ypserv on chkconfig yppasswdd on chkconfig ypxfrd on chkconfig ypbind on chkconfig rpcidmapd on

10. Initialize NIS map

If hostname does not resolve to the IP address you want ypserver to run on then you need to temporarily redefine hostname to a value that resolves to the desired IP. On compute nodes the hostname typically resolves to the Management IP (1 GB) interface. By setting hostname to the private IB hostname one could use ypserver on that network instead.

To create the NIS maps, enter at command prompt

11. Validate ypservers

Verify that /var/yp/ypservers has the master and slave servers defined. The process in step 10 should have added them. If not add them in manually.

[root@nis1 ~]# more /var/yp/ypservers nis1.us.oracle.com nis2.us.oracle.com [root@nis1 ~]#

12. Start All NIS Services

At the command prompt enter:

service portmap restart service rpcidmapd restart service ypserv start service ypbind start service yppasswdd start service ypxfrd start

Draft Disclaimer - Most content here is in it's final form but I'm still looking over screenshots, code samples and some formatting. Should be completed shortly.

Introduction

NIS or Network Information Services, originally named Yellow Pages (YP), is a client server directory service protocol that is widely used to distribute system configuration data such as user, group and host names in a computer network. It was originally developed by Sun (now Oracle) and is now licensed to virtually all Unix systems.

This is the first in a couple of blog posts on how to configure a basic NIS setup and also how NIS is being used/configured in ExaLogic and why. I will start with stepping through a setup of a VirtualBox env. completely contained on my laptop so that if you want to re-create the setup in this blog post all the info should be available.

  Environment Setup

In a typical NIS setup you will have one host (physical or virtual) acting as the NIS Master and one or more hosts configured as backups, NIS Slaves. I'm using the term Compute Node throughout this blog post as it is the way that physical servers are referred to in ExaLogic. Later when I will touch on ExaLogic Virtual I will use the term vServer which is a Virtual Machine in ExaLogic terminology.

In my setup I'm using Virtual Machines running under VirtualBox to simulate a small network with 3 Servers, Compute Nodes. Between these Compute Nodes I will have an internal network that is only accessible from these three virtual machines. When you install VirtualBox it will have an internal DHCP server that can be configured for different network setups that determines how your virtual machines will communicate. Chapter 6 in the VirtualBox manual describes all networking modes and it's worth reading. The VirtualBox PM also wrote a very good blog post on the topic some time ago. I also have some other blogposts on regarding VirtualBox here.

The Virtual Machines themselves are just default installs of OL 5.6 and they are named NIS1, NIS2 and NIS3 (Guest host names)

The command below (run it on the host where VBox is installed) will create the internal network that we will use between the three Virtual Machines.

VBoxManage dhcpserver add --netname nisnet --ip 192.168.24.1 --netmask 255.255.255.0 --lowerip 192.168.24.2 --upperip 192.168.24.254 --enable

List the networks on your VirtualBox host (host will always refer to the physical machine here and guest will always refer to one of the virtual machines):

  VirtualBox Network Setup

Screenshot below shows how the internal network created above is configured in VirtualBox. Internal Networks are identified by name and each defined network will have it's own DHCP server running on your host and distribute IP's to Guests that enable an internal adapter referencing the name of the network. The IP will not change as long as the MAC address stays the same. In my env. I disabled the DHCP feature in my Guests and instead configured them with a static IP in the same range. I only did that to make sure that I nothing ever changed in the Guest OS. I also added entries in /etc/hosts on each Guest OS.

Networks shown in the VirtualBox Guest

See the output from ifconfig inside one of my Guests (aka Compute Nodes).

http://mobassh.mobatek.net/

Some key features as listed on their site:

Execute commands on a remote Windows computer

Transfer files through an encrypted channel

Retrieve information about the remote computer

Make backups of your computers over the network

Silently install software on remote Windows computers

Silently administer the remote Windows computer (the user can stay connected: the commands are run in background mode)

Pretty cool for a Windows box...

 You can easily try it on a Windows host after install by using MobaXterm on the same host and connect to localhost.

Recently a colleague sent out an email to our team pointing us to a little Windows based utility program called MobaXterm. 

If you ever used Putty on Windows to access a system via SSH you've only scratched the surface of what MobaXterm can do. In fact, it's so good that I think it's worth while to start a Windows VM on my Mac just to run this tool. I also got a hint from one of the Developers that they are considering a Mac/Linux version. Yes, I know all they discrete features are already there on those platforms. It's just not packaged as well as here. 

From their website:

MobaXterm key features :

Free X server fully configured (based on Xorg)

Tab-based terminal based on PuTTY / MinTTY with antialiased fonts and macro support

Easy DISPLAY exportation from any remote host

X11-Forwarding capability in OpenSSH

Several Unix/Linux commands based on Cygwin (rsync, wget, sed, awk, grep, cd, ls, cat, cp, ...)

MobaXterm is a single executable (exe file) and runs without installation so that you can start it from an USB stick or from anywhere on your system (dropbox folder perhaps)

A session manager with all the network clients you need: RDP, VNC, SSH, telnet, rsh, FTP, SFTP and XDMCP

Group sessions in Folders and open all of them with one click (right-click on the folder)

Built in ftp server, start it with "service ftp start"

Built in http server, start it with "service httpd start"

List of features: http://mobaxterm.mobatek.net/features.html

Some screenshots from my env.:

Above you can see how X11 Forwarding is automatically configured and any X11 app is opened locally on your Windows machine (xclock in this case).

 Two SSH sessions opened in multi-execution mode. This means that any command you type is executed in all sessions.

 Logging of all output in a local file (one file per session).

SSH Bouncing configured. Very easy and straight forward way to reach hosts behind Firewalls or hosts with non-routable IP's. One scenarios could be connections to Virtual Machines that only communicates via Host only network like in the screenshot above. 

Although VirtualBox has gotten a facelift lately with more features added to the GUI there is still a lot of  things that can only be done on the command line and then there are situations when the command line is the only choice or option. I'll just give some examples below but the full list of what's available can be found here.

VBoxManage is the command line interface to VirtualBox and it will give you complete control over your VBox environment. VBoxManage is always used together with different subcommands that specifies what action you want to take, "list", "createvm", "startvm" etc.

Some examples:

List the VM's (guests) registered on your host (the physical machine):

ok, first mistake, of course I need to specify what to list

That looks better. We can see that I have 5 VM's on my Mac. To perform an action on one of them like startvm  or stopvm I can use either the descriptive name or the VM's UUID (which is the VM's internal name).

As we can see the VM is now starting on my Mac. What we don't see in the screenshot above is that the VM is actually starting it's GUI on my desktop. What if I didn't want to show the GUI. This could be a remote Server or a machine with no display. The solution is to run the VM in what's called headless mode.

VBoxManage startvm "VM name" --type headless

This will start the VM without a local GUI. VBoxHeadless that is being used here is simple just another front-end that will replace the normal GUI. Instead it will act as a Remote Desktop Server and deliver it's output as VRDP data. Any RDP client can now be used to display the output. That client could be running on your iPhone/iPad, Linux, Mac or Windows machine.

As an alternative to the command above you can use VBoxHeadless direct on the command line.

VBoxHeadless -startvm "VM name" &

More about VBoxHeadless here. One thing to note is that since there is no GUI you will now have to access the VM using an RDP client (Windows Remote Terminal, Remmina, CoRD etc.). When you start the VM in headless mode the RDP protocol is always on but it can be explicitly turned off if you for instance want to use only SSH to access the VM.

VirtualBox has some very powerful networking features and some of these features are only available using VBoxManage. You can for instance create private networks between for VM's. For these to work smooth you need a DHCP server and VBox provides one.

List the active dhcp servers on your machine:

- VBoxManage list dhcpservers

Create one:

VBoxManage dhcpserver add --netname ovmnet --ip 192.168.60.1 --netmask 255.255.255.0 --lowerip 192.168.60.2 --upperip 192.168.60.100 --enable

Two or more VM's can now just add a network adapter and use the -netname above to join the network by the name "ovmnet".

New feature in VBox 4.1

Something that most competitors have had for a while is the ability to clone a VM. In VBox you could also do that but with less features and in a somewhat primitive way using VBoxManage, see sample below.

VBoxManage clonehd myoldfile.vmdk mynewfile.vmdk --format VMDK --variant Split2G

From 4.1 there is now support for cloning in the GUI. Both Full Clones and Linked Clones. It's a simple, two step process.

There is still usage for the command line as it can do some things that the GUI can't. Like in the example above where a disk file is cloned a also split into smaller segments.

That way I don't have to choose:-)

http://www.choosyosx.com/

Printopia is a brilliant little app that will let you print from any iOS device to any printer connected to the Mac where it's installed. A bargain at $20.

http://www.ecamm.com/mac/printopia/

I have heard that statement many times from new Mac users.

You will see forum threads like this one, http://forums.macrumors.com/showthread.php?t=154973

"does apple have a native image viewer like in windows? i like how in windows i was able to just click arrows to scroll through pictures, and i could slideshow easily."

The image viewer in Mac OS X is right there, in front of you. The Finder. This will allow you to view both image files such as jpg and gif but also RAW files as the support for RAW files is built in to Mac OS X (there is no such support on Windows).

Just navigate to the Folder where you have your images, select all or some of them and hit the Space key.

That's it!

Avoid loosing it;-)

Sounds easy and for the most part it is but in the last week I know of 3 colleagues that have lost their laptops. All stolen from their cars. A car is not (a) safe for anything, not even itself:-) Ask any Police or Insurance company. You just don't keep anything valuable in it. Period. For other locations there are security gadgets like security wires and locks and backpacks like the ones from PacSafe. I have one of these backpacks that I use sometimes when I travel. It allows me to lock the backpack inside the car or anywhere and if the thief doesn't have some serious tools  he can't walk away easily with it.

If you lost it anyway

Backups

I'm working on a full blog post on backup strategies so  just a couple of short pointers here.

Do it! A bad backup is better than no backup.

Backups should be automatic.

For every drive you need to backup you need two backup drives and they should be on a rotating schedule, maybe weekly. Drives are cheap. Consider loosing all your work, photos, emails etc. and you'll see that drives are cheap.

I use backup tools that clones my drives meaning that the backup drive is an exact copy of the source drive. Carbon Copy Cloner, SuperDuper!, Synk Pro are some examples for a mac user. For Windows and Linux there are similar tools. The other type of backup tool will backup selected folders and keep versions of your files. On Mac you have Time Machine which is one of the best tools out there.

One backup drive should always be off site on a different location. I keep one at home and one at work.

Consider an online backup tool. I use Crashplan(.com). It runs on all platforms and is completely automatic. For less than $5/month your files will be backed up as long as the computer is connected to internet. I have almost 700GB online by now and the storage is unlimited. The software is free and will backup to another computer or external drive for free. It just works. I used another provider for a couple of years, Backblaze(.com). It was good at first but when the volume and number of files increased the backup client started to load down my computer. 

Just do it!

 Tracking software

There are numerous software packages that allows you to track the usage of your computer once it's lost and help you or the Police to recover it. Most thieves are stupid and non-technical. They will start using the laptop asap or sell it asap to some other non-technical person. For these tracking programs to work the computer must be able to get online so make it easy to use and get online.

Undercover from orbicule.com is one of the best tracking software packages for Mac OS X. I have it installed on all my Macs. Once installed it will communicate with orbicule.com. I think the call back is every 6 minutes. If your laptop is stolen you can login to their website with your account (or contact them by phone) and activate the tracker on the lost laptop. Once activated the software will start to phone home with screenshots, ip, webcam photos etc. With this info Orbicule will assist you and the local Police to recover the lost laptop. I think I paid $60 for a Family pack. More info here, http://www.orbicule.com/undercover/mac/index.html. Orbicule has some other related products as well so go check their website. In the section "What if recovery fails?" on the link above there are a couple of features described that differentiates Undercover from Prey (below).

Prey from preyproject.com will do a similar job and it's free for 3 computers. It's cross platform (linux/mac/windows). Since it's free I think you're on your own with the data captured and to work with the local Police your self. They also have a new tool for phones that will go in beta soon. I'm on the beta program so I'll update this post when I know more.

As I mentioned above these tracking tools only work if the computer is online so you need to leave that possibility open so enable the Guest Account on Mac OS X and there should be no password. I believe you can do the same on Windows. Your own account and the Admin account should of course be protected with a strong password (see links below to articles on passwords).

Another bonus with online backup tools mentioned above is that they will continue to operate after the laptop is stolen and if the thief is using it his data might end up online in your account. The guest account on a Mac will reset when you log out and all data is erased but as long as someone is logged in the data stays there and will be backed up.

On a Mac you can also enable a firmware password, http://orbicule.blogspot.com/2007/05/what-you-need-to-know-about-apple.html

Slink, not really a tracking software but it has some useful features. It is a remote control software that allows you to connect to your as long as the remote Mac is connected to internet. The Mac you want to connect to will have a system service running at all times and with the remote client you can connect to the Mac with the service. Once connected (via an ssh tunnel) the service will forward Bonjour Based network services and you can now login to the stolen Mac. More info on www.slinkware.com. If this is your only usage of Slink for now you don't need to buy a license since the server component is always free. Just take a note of the unique ID it generates and if your Mac is stolen you can buy a license, install it on another mac and connect to your Mac.

Useful links on passwords....

Why Multi-word Phrases Make for More Secure Passwords Than Incomprehensible Gibberish

http://howsecureismypassword.net/

Had no idea VBox could do tricks like this.

http://www.youtube.com/watch?v=1DcaDFHvozU

Earlier today I managed to overload my Dell Precision M6500 so it got totally unresponsive. It has 16GB RAM and a Quad Core i7 so what did I do? Started one too many VBox instances I guess. I had 3 VM's running (2 VM's with SOA/ECM/IPM & 11g DB and 1 VM running a full eBusiness Suite 11i). When the 4th VM started running some serious swapping occurred. No wonder...

Since I run LInux (Debian) on the box I managed to ssh into it from my Mac but even command line was slooooow. Login took at least a minute. With the commands below I managed to get control back:

No need to explain this command, right??

$ VBoxManage list runningvms

"Imaging-New" {beaefc06-b079-4ad6-8f3a-66f47647d04e}

"EBS11i" {b940c13a-65b5-4f91-a6ab-3c926728db33}

"Solaris10_9-10" {69701a10-8d1a-4c73-819f-2c4cd671ae65}

"OEL64bit-XE11g" {005dd880-bfa9-47fc-a748-8470a4d68ae1}

 Next I just need to either stop or suspend my VM's

$ VBoxManage controlvm Imaging-New savestate

$ VBoxManage controlvm EBS11i savestate

$ VBoxManage controlvm Solaris10_9-10 savestate

$ VBoxManage controlvm OEL64bit-XE11g savestate

Done! I'm back in business as my laptop slowly recovers. The commands above are the same on all platforms where VirtualBox runs.

Short answer is that there is no need to convert a VMware VM to VBox format as they run the same format. Easy:-)

There are however a few steps to get from VMware to VBox and here they come:

Create a new VM in VBox but skip the step where you create the disk file. Just uncheck the box "Boot Hard Disk"  

Now you need to copy (or move) the vmdk files from your VMware VM to the folder that VBox created for the new VM. Take note of how these disks where connected in VMware, IDE, SCSI or SATA.  

In VBox you open the settings dialog for the VM, go to the Storage section and add the disks using the same controller as they had in VMware. The order is significant, add the boot disk first. If it's a split vmdk file you just need to add the first segment.  

Start the VM in VBox and install the Guest Additions and uninstall VMware Tools.

The steps above should cover the process.

http://forums.virtualbox.org/

http://www.oracle.com/technetwork/community/developer-vm/index.html

http://blogs.sun.com/fatbloke/

Let me know if you find one that should be added to this list.

This should be all the steps (with some screenshots) needed to setup 2 VBox VM's from the same starting point, a VBox appliance (.ova of .ovf file)

Pre-requisites:

Laptop/Desktop with preferably 8GB ram and most likely then also a 64bit OS.  

VirtualBox 4.* with the Extension Pack installed.

Steps:

Create the first instance via Menu File > Import Appliance. Leave all settings as default (Do NOT rename the VM here). The import will take a minute or two.  

In Oracle VM VirtualBox Manager select the imported VM and click Settings and rename it, I will call it Node1 in this example. That's it for now. Click OK.  

Repeat step 1 & 2 but give this VM a different name, I'll call it Node2.  

Next we need to configure the two VM's to be able to talk to each other. The networking options are numerous. Best option here is to configure an Internal Network. In both VM's, enable and configure the second network adapter as shown below. You can enter any name you want in the Name. 

Very important! Click on the green icon next to the Mac Address field. VirtualBox will not give network adapters new and unique Mac Address during import. This is will cause 2 or more VM's using DHCP (next step) to get the same IP which of course will not work. Make sure that all VM's have an unique Mac Address before moving to the next step. This is not a bug according to the VBox Dev. team. Apparently some users wanted it this way...  

Now there are two options to give these two VM's IP Addresses, Static or Dynamic (DHCP). If you chose static there is nothing more that needs to be done when it comes to VirtualBox. Just configure the network in each VM's Guest OS as you would if it was a physical machine. There is no difference whatsoever. If you want a DHCP assigned network address there is one more step in VirtualBox, configure a DHCP Server.VirtualBox provides a command line tool to configure a DHCP Server. The command below will create a new DHCP server for the network named "intnet" (default network name for the internal network). Run it on you laptop/desktop where you have VBox installed. VBoxManage dhcpserver add --netname intnet --ip 192.168.1.1 --netmask 255.255.255.0 --lowerip 192.168.1.2 --upperip 192.168.1.100 --enable  

Start your VM's. In most cases  everything will just work and the new network adapter will get an IP in the range specified above.

  The mandatory reading is of course the manual;-) Chapter 6 deals with networking http://www.virtualbox.org/manual/ch06.html

Very good blogpost on the topic: https://blogs.oracle.com/fatbloke/entry/networking_in_virtualbox1