Linux Tech Tips

I use virtual box for all my testing and validation activities. It comes too often that I have a virtual box VM window open & I want to switch to my host machine to see some stuff like tutorials etc.. If you press the alt+tab combination it just works inside the VM & doesn't switches to host machine. In these scenarios you can press the host key once ( not hold it ) & then whatever you press goes to host machine. So in general where host key is the default Right Ctrl, just press Right Ctrl once & now press the alt+tab & it will switch you out to host machine. This is really helpful when you have the VM windows open or you're working on seamless mode. Hope it help others too.

I'm a Linux System Admin & I play with lots of virtual machines to try & test various software & services. I use Virtual Box for creating virtual machine. Everything works fine except the part of installing same virtual machine again & again which takes a lot of time installing & configuring it. Recently I came across a tool called Vagrant which can automate that process or at least can make it easy for us to make a base image & then create virtual machines from that image without any worry. Now the real work:- Make sure you've Virtual Box installed on your machine, if not already done, download from  https://www.virtualbox.org/wiki/Downloads  & install it. Its available for almost all popular platforms. Download Vagrant from  http://downloads.vagrantup.com/  & install it. Binary packages available for MAC, Windows, debian & RPM based systems. I used Centos 6 heavily so I installed Centos 6. Location specific mirro...

So you need to add an additional hard disk to your VM running the Centos/Redhat/Suse family of operating system, but its in production and you can not reboot it. So how do you go about it? Well, it is rather easy! First, open the "edit settings" window, within the VM, either from the console menu, or by right clicking in the VM through the virtual infrastructure client. Add a hard disk and configure it with the size you require. Finally accept the changes and close the window. After a few seconds, the virtual infrastructure client will shown the reconfiguration being complete. Now logon to the operating system of the VM, as the root user - or use sudo. You will see that the VM does not see the new disk, i.e. running the command: fdisk -l Shows only the existing disks, there is no sign of the new one. What we need to do is, re-scan the SCSI bus, without rebooting the VM. To do this run the following command: echo "- - -...

Migrating to another virtual machine program can be intimidating. if you already have your virtual machines set up they way you like them, you don’t necessarily have to install them from scratch – you can migrate your existing virtual machines. VirtualBox and VMware use different virtual machine formats, but each supports the standard Open Virtualization Format. Convert your existing virtual machine to OVF or OVA and you’ll be able to import it into another virtual machine program. Unfortunately, this may not always work perfectly, as VirtualBox and VMware both seem to use slightly different OVA/OVF implementations that aren’t entirely compatible. If this doesn’t work, you may want to reinstall your virtual machine’s guest operating system from scratch. VirtualBox to VMware Before migrating a virtual machine from VirtualBox to VMware, ensure it’s “powered off” in VirtualBox – not suspended. If it’s suspended, launch the virtual machine and shut it down. ...