Virtualisation | Technology Tales

Lightening of desktop background images on Linux Mint Debian Edition running in Virtualbox

22nd October 2018

After a recent upgrade to Linux Mint Debian Edition 3 in a VirtualBox virtual machine that I had running its predecessor, I began to notice that background images were being loaded with more washed out of faded colours. This happened at startup so selecting another background image worked as intended until the same thing happened to that after a system restart.

This problem is not new and has affected the Cinnamon desktop in the main Linux Mint variant (the one that is based on Ubuntu) and issuing the following command in a terminal session is a suggested solution:

gsettings set org.cinnamon.muffin background-transition fade-in

In my case, that solved the problem and desktop background image display is as it should be since I executed the above. All it took was a change to a system setting.

Compressing a VirtualBox VDI file for a Linux guest

6th June 2016

In a previous posting, I talked about compressing a virtual hard disk for a Windows guest system running in VirtualBox on a Linux system. Since then, I have needed to do the same for a Linux guest following some housekeeping. The Linux distribution used is Debian so the instructions are relevant to that and maybe its derivatives such as Ubuntu, Linux Mint and their kind.

While there are other alternatives like dd, I am going to stick with a utility named zerofree to overwrite the newly freed up disk space with zeroes to aid compression later on in the process for this and the first step is to install it using the following command:

apt-get install zerofree

Once that has been completed, the next step is to unmount the relevant disk partition. Luckily for me, what I needed to compress was an area that I reserved for synchronisation with Dropbox. If it was the root area where the operating system files are kept, a live distro would be needed instead. In any event, the required command takes the following form with the mount point being whatever it is on your system (/home, for instance):

sudo umount [mount point]

With the disk partition unmounted, zerofree can be run by issuing a command that looks like this:

zerofree -v /dev/sdxN

Above, the -v switch tells zerofree to display its progress and a continually updating percentage count tells you how it is going. The /dev/sdxN piece is generic with the x corresponding to the letter assigned to the disk on which the partition resides (a, b, c or whatever) and the N is the partition number (1, 2, 3 or whatever; before GPT, the maximum was 4). Putting all this together, we get an example like /dev/sdb2.

Once, that had completed, the next step is to shut down the VM and execute a command like the following on the host Linux system ([file location/file name] needs to be replaced with whatever applies on your system):

VBoxManage modifyhd [file location/file name].vdi --compact

With the zero filling in place, there was a lot of space released when I tried this. While it would be nice for dynamic virtual disks to reduce in size automatically, I accept that there may be data integrity risks with those so the manual process will suffice for now. It has not been needed that often anyway.

Compressing a VirtualBox VDI file for a Windows guest running on a Linux Host

11th February 2016

Recently, I had a situation where my the VDI files for my Windows 10 virtual machine expanded in size all of a sudden and I needed to reduce them. My downloading maps for use with RouteBuddy may have been the cause so I moved the ISO installation files onto the underlying Linux Mint drives. With that space, I then set to uncovering how to compact the virtual disk file and the Sysinternals sdelete tool was recommended for clearing unused space. After downloading, I set it to work in a PowerShell session running on the guest operating system from its directory using the following command:

.\sdelete -z [drive letter designation; E: is an example]

From the command prompt, the following should do:

sdelete -z [drive letter designation; E: is an example]

Once, that had completed, I shut down the VM and executed a command like the following from a bash terminal session:

VBoxManage modifyhd [file location/file name].vdi --compact

Where there was space to release, VDI files were reduced in size to return more disk space. More could be done so I will look into the Windows 10 drives to see what else needs to be moved out of them.

Migrating a virtual machine from VirtualBox to VMware Player on Linux

1st February 2015

The progress of Windows 10 is something that I have been watching. Early signs have been promising and the most recent live event certainly contained its share of excitement. The subsequent build that was released was another step in the journey though the new Start Menu appears more of a work in progress than it did in previous builds. Keeping up with these advances sometimes steps ahead of VirtualBox support for them and I discovered that again in the last few days. VMware Player seems unaffected so I thought that I’d try a migration of the VirtualBox VM with Windows 10 onto there. In the past, I did something similar with a 32-bit instance of Windows 7 that subsequently got upgraded all the the way up to 8.1 but that may not have been as slick as the latest effort so I thought that I would share it here.

The first step was to export the virtual machine as an OVF appliance and I used File > Export Appliance… only to make a foolish choice regarding the version of OVF. The one that I picked was 2.0 and I subsequently discovered that 1.0 was the better option. The equivalent command line would look like the following (there are two dashes before the ovf10 option below):

VboxManage export [name of VM] -o [name of file].ova --ovf10

VMware have a tool for extracting virtual machines from OVF files that will generate a set of files that will work with Player and other similar products of theirs. It goes under the unsurprising name of OVF Tool and it usefully works from a command line session. When I first tried it with an OVF 2.0 files, I got the following error and it stopped doing anything as a result:

Line 2: Incorrect namespace http://schemas.dmtf.org/ovf/envelope/2 found.

The only solution was to create a version 1.0 file and use a command like the following (it’s a single line though it wraps over two here and there are two dashes before the lax switch):

ovftool --lax [name of file].ova [directory location of VM files]/[name of file].vmx

The --lax option is needed to ensure successful execution even with an OVF 1.0 file as the input. Once I had done this on my Ubuntu GNOME system, the virtual machine could be opened up on VMware Player and I could use the latest build of Windows 10 at full screen, something that was not possible with VirtualBox. This may be how I survey the various builds of the operating that appear before its final edition is launched later this year.

Automatically enabling your network connection at startup on CentOS 7

15th August 2014

The release of CentOS 7 stoked my curiosity so I gave it a go in a VirtualBox virtual machine. It uses GNOME Shell in classic mode so the feel is not too far removed from that of GNOME 2. One thing to watch though is that it needs at least version 4.3.14 of VirtualBox or the Guest Additions kernel drivers will not compile at all. That might sound surprising when you learn that the kernel version is 3.10.x and that for GNOME Shell is 3.8.4. Much like Debian production releases, more established versions are chosen for the sake of stability and that fits in with the enterprise nature of the intended user base. Even with that more conservative approach, the results still please the eye though attempting to change the desktop background picture managed to freeze the machine. Other than that, most things work fine.

Even so, there are unexpected things to be encountered and one that I spotted was that network connectivity needed to switched on every time the VM was started. The default installation gives rise to this state of affairs and it is a known situation with CentOS from at least version 6 of the distribution and is not so hard to fix once you know what to do.

What you need to do is look for the relevant configuration file in /etc/sysconfig/network-scripts/ and update that. Using the ifconfig command, I found that the name of the network interface. Usually, this is something like eth0 but it was enp0s3 in my case so I had to look for a file named ifcfg-enp0s3 and edit that. The text that is sought is ONBOOT=no and that needs to become ONBOOT=yes for network connections to start automatically. To do something similar from the command line, CentOS had suggested the following:

sed -i -e ‘s@^ONBOOT=”no@ONBOOT=”yes@’ ifcfg-enp0s3

The above uses sed to do an inline (and case insensitve) edit of the file to change the offending no to a yes, once you have dropped in the /etc/sysconfig/network-scripts/ directory. My edit was done manually with Gedit so that works too. One thing to add is that any file editing needs superuser privileges so switching to root with the su command and using sudo is in order here.

Dropping back to a full screen terminal session from a desktop one in Linux

29th May 2014

There are times when you might need to drop back to a full screen terminal session from a graphical desktop environment when running Linux. One example that I have encountered is the installation of Nvidia’s own graphics drivers on either Ubuntu or Linux Mint. Another happened to me on Arch Linux when a Cinnamon desktop environment update left me without the ability to open up a terminal window. Then, the full screen command allowed me to add in an alternative terminal emulator and Tech Drive-in’s list came in handy for this. there might have been something to sort on a FreeBSD installation that needed the same treatment. This latter pair happened to me on sessions running within VirtualBox and that has its own needs when it comes to dropping into a full screen command line session and I will come to that later.

When running Linux on a physical PC, the keyboard shortcuts that you are CTRL + ALT + F1 for entering a full screen terminal session and CTRL + ALT + F7 for returning to the graphical desktop again. When you are running a Linux guest in VirtualBox and the host operating system also is Linux, then the aforementioned shortcuts do not work within the virtual machine but instead affect the host. To get the guest operating system to drop into a full screen terminal session, the keyboard shortcut you need is [Host Key] + F1 and the default host key is the right hand CTRL key on your keyboard unless you have assigned to something else as I have. The exit the full screen terminal session and return to the graphical desktop again, the keyboard shortcut is [Host Key] + F7.

All of this works with GNOME and Cinnamon desktop environments running in X sessions and I cannot vouch for anything else unless alternatives like Wayland come my way. Hopefully, this useful functionality applies to those other set-ups too because there are times when a terminal session is needed to recover from a mishap, rare though those thankfully are and they need to be very rare if not non-existent for most users.

Installing FreeBSD in a VirtualBox Virtual Machine

2nd March 2014

With UNIX being the basis of Linux, I have a soft spot for trying out any UNIX that can be installed on a PC. For a while, I had OpenSolaris on the go and even vaguely recall having a look at one of the BSD’s. However, any recent attempt to install one of the latter, and there are quite a few around now, got stymied by some sort of kernel panic caused by using AMD CPU’s. With the return to the Intel fold arising from the upgrade of my main home PC last year, it perhaps was time to try again.

The recent release of FreeBSD 10.0 was the cue and I downloaded a DVD image for a test installation in a VirtualBox virtual machine with 4 GB of memory and a 32 GB virtual hard drive attached (expanding storage was chosen so not all the allocated space has been taken so far). The variant of FreeBSD chosen was the 64-bit x86 one and I set to installing it in there. Though not as pretty in appearance as those in various Linux distros, the installer was not that user unfriendly to me. Mind you, I have experience of installing Arch Linux so that might have acclimatised me somewhat.

Those installation screens ask about the keyboard mapping that you want and I successfully chose one of the UK options. There was limited opportunity for adding extras though there was a short list of few from which I made some selections. User account set up also was on offer and I would have been better off knowing what groups to assign for my personal user account so as to have to avoid needing to log in as root so often following system start up later. Otherwise, all the default options were sufficient.

When the installation process was complete, it was time to boot into the new system and all that was on offer was a command line log in session. After logging in as root, it was time to press pkg into service in order to get a desktop environment in place. The first step was to install X:

pkg install xorg

Then, it was time to install a desktop environment. While using XFCE or KDE were alternatives, I chose GNOME 2 due to familiarity and more extensive instructions on the corresponding FreeBSD handbook page. Issuing the following command added GNOME and all its helper applications:

pkg install gnome2

So that GNOME starts up at the next reboot, some extra steps are needed. The first of these is to add the following line into /etc/fstab:

proc /proc procfs rw 0 0

Then, two lines were needed in /etc/rc.conf:

gdm_enable=”YES”
gnome_enable=”YES”

The first enables the GNOME display manager and the second activates other GNOME programs that are needed for a desktop session to start. With each of these in place, I got a graphical login screen at the next boot time.

With FreeDSB being a VirtualBox Guest, it was time to consult the relevant FreeBSD manual page. Here, there are sections for a number of virtual machine tools so a search was needed to find the one for VirtualBox. VirtualBox support for FreeBSD is incomplete in that there is no installation media for BSD systems though Linux and Solaris are supported along with Windows. Therefore, it is over to the FreeBSD repositories for the required software:

pkg install virtualbox-ose-additions

Aside from the virtual machine session not capturing and releasing the mouse pointer automatically, that did everything that was needed even if it was the open source edition of the drivers and their proprietary equivalents. To resolve the mouse pointer issue, I needed to temporarily disable the GNOME desktop session in /etc/rc.conf to drop down to a console only session where xorg. conf could be generated using the following commands:

Xorg -configure
cp xorg.conf.new /etc/xorg.conf

In the new xorg.conf file, the mouse section needs to be as follows:

Section “InputDevice”
Identifier “Mouse0”
Driver “vboxmouse”
EndSection

If it doesn’t look like the above and it wasn’t the case for me then it needs changing. Also, any extra lines from the default set up also need removing or the mouse will not function as it should. The ALT+F1 (for accessing GNOME menus) and ALT+F2 (for running commands) keyboard shortcuts then become crucial when your mouse is not working as it should and could avert a panic too; knowing that adjusting a single configuration file will fix a problem when doing so is less accessible is not a good feeling as I discovered to my own cost. The graphics settings were fine by default but here’s what you should have in case it isn’t for you:

Section “Device”
### Available Driver options are:-
### Values: <i>: integer, <f>: float, <bool>: “True”/”False”,
### <string>: “String”, <freq>: “<f> Hz/kHz/MHz”
### [arg]: arg optional
Identifier “Card0”
Driver      “vboxvideo”
VendorName “InnoTek Systemberatung GmbH”
BoardName   “VirtualBox Graphics Adapter”
BusID       “PCI:0:2:0”
EndSection

The next step is to ensure that your HAL settings are as they should. I needed to create a file in /usr/local/etc/hal/fdi/policy called 90-vboxguest.fdi that contains the following:

<?xml version=”1.0″ encoding=”utf-8″?>

<deviceinfo version=”0.2″>
<device>
<match key=”info.subsystem” string=”pci”>
<match key=”info.product” string=”VirtualBox guest Service”>
<append key=”info.capabilities” type=”strlist”>input</append>
<append key=”info.capabilities” type=”strlist”>input.mouse</append>
<merge key=”input.x11_driver” type=”string”>vboxmouse</merge>
<merge key=”input.device” type=”string”>/dev/vboxguest</merge>
</match>
</match>
</device>
</deviceinfo>

With all that set, it is time to ensure that the custom user account is added to the wheel and operator groups using this command:

pw user mod [user name] -G wheel operator

Executing the above as root means that the custom account can run the su command so that logging in as root at the start of a desktop session no longer is needed. That is what being in the wheel group allows and the anyone in the operator group can shut down or restart the system. Both are facilities readily available in Linux so I fancied having them in FreeBSD too.

Being able to switch to root in a terminal session meant that I could go on to add software like Firefox, Libreoffice, GIMP, EMACS, Geany, Netbeans, Banshee and so on. There may be a line of opinion that FreeBSD is a server operating system but all of these make it more than passable for serving as a desktop one too. There may be no package management GUI as such and the ones that come with GNOME do not work either but anyone familiar with command line working will get around that.

FreeBSD may be conservative but that has its place too and being able to build up a system one item at a time teaches far more than getting everything already sorted in one hit. So far, there is enough documentation to get me going and I hope to see where else things go too. So far, the OS hasn’t been that intimidating and that’s good to see.

Sorting out hogging of the Super (or Windows) Key by GNOME Shell

12th November 2013

Most of the time, GNOME Shell’s use of the Super (or Windows) key on a standard keyboard to open up its dash area is no issue and is a handy counterpart to what you might do in Windows, especially in its latest incarnations. However, it does cause trouble if you are using a VirtualBox virtual machine with Windows installed in there. While VMware Player is immune to this problem I thought that I would see if there was a workaround for it.

The issue might arise from VirtualBox’s non-grabbing of the Super key like others but a solution can be found in GNOME itself. Opening up dconf-editor and navigating to org > gnome > mutter. In there, you will find a setting called overlay-key and this can be changed. One option is to delete the SUPER_L value and leave it that way. My own preference was to set it to a different key and, to do that, I needed to know what the various key identifiers were. To get these, I ran the following command (just replace any quotes with alternatives in the shell before executing this):

xev | grep -A2 --line-buffered ‘^KeyRelease’ | sed -n ‘/keycode /s/^.*keycode $[0-9]*$.* (.*, $.*$).*$/\1 \2/p’

This opened up an Event Tester window that will need closing when testing is complete. More importantly, the aliases for any keys that were pressed to are issued to the terminal session so you can see what’s what. Initially, the one for the Alt Gr key appealed to me and I set “ISO_Level3_Shift” as the value of the overlay-key property in dconf-editor. When that didn’t work, I set the value to “Menu” and it behaved as expected. While this will mean that context menus will have to be accessed by right-clicking in a Windows session, that is what I do anyway so there isn’t going to be much of a loss in what I have done. A function key might have been another option but I reckon that the context menu key will do me.

Creating a test web server using Ubuntu Server 13.04 and VirtualBox

1st September 2013

Having seen Linux Format cover tools like Vagrant and Puppet that manage virtual machines, I have been attracted by the prospect of a virtual web server running on my own PC. Certainly, having the LAMP software stack in a VM means that the corresponding tools don’t need to be added to a host system should its operating system need a fresh installation.

As intriguing as tools like Vagrant may be, I decided that I needed to learn a bit more about getting server instances set up in VirtualBox anyway. Thus, I went and downloaded the latest version of Ubuntu Server and gave that a go. One lesson that I learned was that Bridged Networking needs to be added to the VM before installation of the operating system unless you fancy overcoming the challenge of getting Ubuntu Server to recognise an altered or additional network interface. In my case, I added an extra adapter for the Bridged Networking and left the original in place as NAT. The reason for having Bridged Networking set up is that it allows access to the virtual web server from the host once you know the IP address and that information can be obtained by executing the ifconfig command on the virtual machine.

With the networking sorted, the next step was to install the 64-bit edition of Ubuntu Server. Unlike its desktop counterpart, this is all driven by text menus but remains fairly intuitive and there is hardly anything there that you wouldn’t see with another Linux distribution. A useful addition is the addition of a menu to select the type of server services that you’d like to see installed. From this, I chose the web server and SSH options and I seem to remember that there was a database server option too. If there was an FTP server option, I would have chosen that too but it was no ordeal to add ProFTPd later on anyway.

All of this set was done through the VirtualBox GUI just to keep life more straightforward. Even so, I only selected 12 MB of video memory and was tempted to cut the overall memory back from 512 MB but leaving things be for now. However, what I have begun to do is start and stop the virtual machine from the command line since servers are headless operations anyway. With SSH enabled, there is little need to have the VirtualBox GUI going. The command for starting the server is below:

VBoxManage startvm "Ubuntu Server" --type=headless

There is a VBoxHeadless command for the same end too but VBoxManage does what I need. The startvm option is what tells VBoxManage to start the server and the virtual machine’s name is enclosed in quotes. The --type=headless ensures that no window pops up. To stop the virtual web server cleanly, a command like the following is needed:

VBoxManage controlvm "Ubuntu Server" acpipowerbutton

Again, the VBoxManage command gets used and the acpipowerbutton option ensures that a clean shutdown is performed. Not doing so results in the server not fully starting up according to my experiences thus far. Getting the virtual web server to start and stop with the host machine itself starting and stopping but this looks more complex so I plan to leave things a while before trying that experiment.

A look at Windows 8.1

4th July 2013

Last week, Microsoft released a preview of Windows 8.1 and some hailed the return of the Start button but the reality is not as simple as that. Being a Linux user, I am left wondering if ideas have been borrowed from GNOME Shell instead of putting back the Start Menu like it was in Windows 7. What we have got is a smoothing of the interface that is there for those who like to tweak settings and not available be default. GNOME Shell has been controversial too so borrowing from it is not an uncontentious move even if there are people like me who are at home in that kind of interface.

What you get now is more configuration options to go with the new Start button. Right clicking on the latter does get you a menu but this is no Start Menu like we had before. Instead, we get a settings menu with a “Shut down” entry. That’s better than before, which might be saying something about what was done in Windows 8, and it produces a sub-menu with options of shutting down or restarting your PC as well as putting it to sleep. Otherwise, it is place for accessing system configuration items and not your more usual software, not a bad thing but it’s best to be clear about these things. Holding down the Windows key and pressing X will pop up the same menu if you prefer keyboard shortcuts and I have a soft spot for them too.

New Windows 8.1 Options

The real power is to be discovered when you right click on the task bar and select the Properties entry from the pop-up menu. Within the dialogue box box that appears, there is the Navigation tab that contains a whole plethora of interesting options. Corner navigation can be scaled back to remove the options of switching between applications at the upper left corner or getting the charms menu from the upper right corner. Things are interesting in the Start Screen section. This where you tell Windows to boot to the desktop instead of the Start Screen and adjust what the Start button gives you. For instance, you can make it use your desktop background and display the Start Screen Apps View. Both of these make the new Start interface less intrusive and make the Apps View feel not unlike the way GNOME Shell overlays your screen when you hit the Activities button or hover over the upper left corner of the desktop.

It all seems rather more like a series of little concessions and not the restoration that some (many?) would prefer. Classic Shell still works for all those seeking an actual Start Menu and even replaces the restored Microsoft Start button too. So, if the new improvements aren’t enough for you, you still can take matters into your own hands until you start to take advantage of what’s new in 8.1.

Apart from the refusal to give us back a Windows 7 style desktop experience, we now have a touchscreen keyboard button added to the taskbar.So far, it always appears there even when I try turning it off. For me, that’s a bug and it’s something that I’d like to see fixed before the final release.

All in all, Windows 8.1 feels more polished than Windows 8 was and will be a free update when the production version is released. My explorations have taken place within a separate VMware virtual machine because updating a Windows 8 installation to the 8.1 preview is forcing a complete re-installation on yourself later on. There are talks about Windows 9 now but I am left wondering if going for point releases like 8.2, 8.3, etc. might be a better strategy for Microsoft. It still looks as if Windows 8 could do with continual polishing before it gets more acceptable to users. 8.1 is a step forward and more like it may be needed yet.

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