Turning the world on its head: running VMware on Ubuntu
2nd November 2007
When Windows XP was my base operating system, I used VMware Workstation to peer into the worlds of Windows 2000, Solaris and various flavours of Linux, including Ubuntu. Now that I am using Ubuntu instead of what became a very flaky XP instance, VMware is still with me, which I am using it to keep a foot in the Windows universe. In fact, I have Windows 2000 and Windows XP virtual machines available to me that should supply my Windows needs.
An evaluation version of Workstation 6 is what I am using to power them and I must admit that I am likely to purchase a licence before the evaluation period expires. Installation turned out to be a relatively simple affair, starting with my downloading a compressed tarball from the VMware website. The next steps were to decompress the tarball (Ubuntu has an excellent tool, replete with a GUI, for this) and run vmware-install.pl. I didn't change any of the defaults and everything was set up without a bother.
In use, a few things have come to light. The first is that virtual machines must be stored on drives formatted with EXt3 or some other native Linux file system rather than on NTFS. Do the latter, and you get memory errors when you try starting a virtual machine; I know that I did and that every attempt resulted in failure. After a spot of backing up files, I converted one of my SATA drives from NTFS to Ext3. For sake of safety, I also mounted it as my home directory; the instructions on Ubuntu Unleashed turned out to be invaluable for this. I moved my Windows 2000 VM over and it worked perfectly.
Next on the list was a series of peculiar errors that cam to light when I was attempting to install Windows XP in a VM created for it. VMware was complaining about a CPU not being to run fast enough; 2 MHz was being stated for an Athlon 64 3000+ chip running at 1,58 GHz! Clearly, something was getting confused. Also, my XP installation came to a halt with a BSOD stating that a driver had gone into a loop, with Framebuf fingered as the suspect. I was seeing two symptoms of the same problem and its remedy was unclear. A message on a web forum put the idea of rebooting Ubuntu into my head, and that resolved the problem. For now, I'll be keeping an eye on it, though.
Otherwise, everything seems to be going well with this approach, and that's an encouraging sign. It looks as if my current Linux-based set up is one with which I am going to stay. This week has been an interesting one already, and I have no doubt that I'll continue to learn more as time goes on.
Setting up a test web server on Ubuntu
1st November 2007
Installing all the bits and pieces is painless enough so long as you know what's what; Synaptic does make it thus. Interestingly, Ubuntu's default installation is a lightweight affair with the addition of any additional components involving downloading the packages from the web. The whole process is all very well integrated and doesn't make you sweat every time you need to install additional software. In fact, it resolves any dependencies for you so that those packages can be put in place too; it lists them, you select them and Synaptic does the rest.
Returning to the job in hand, my shopping list included Apache, Perl, PHP and MySQL, the usual suspects in other words. Perl was already there, as it is on many UNIX systems, so installing the appropriate Apache module was all that was needed. PHP needed the base installation as well as the additional Apache module. MySQL needed the full treatment too, though its being split up into different pieces confounded things a little for my tired mind. Then, there were the MySQL modules for PHP to be set in place too.
The addition of Apache preceded all of these, but I have left it until now to describe its configuration, something that took longer than for the others; the installation itself was as easy as it was for the others. However, what surprised me were the differences in its configuration set up when compared with Windows. There are times when we get the same software but on different operating systems, which means that configuration files get set up differently. The first difference is that the main configuration file is called apache2.conf on Ubuntu rather than httpd.conf as on Windows. Like its Windows counterpart, Ubuntu's Apache does use subsidiary configuration files. However, there is an additional layer of configurability added courtesy of a standard feature of UNIX operating systems: symbolic links. Rather than having a single folder with the all configuration files stored therein, there are two pairs of folders, one pair for module configuration and another for site settings: mods-available/mods-enabled and sites-available/sites-enabled, respectively. In each pair, there is a folder with all the files and another containing symbolic links. It is the presence of a symbolic link for a given configuration file in the latter that activates it. I learned all this when trying to get mod_rewrite going and changing the web server folder from the default to somewhere less susceptible to wrecking during a re-installation or, heaven forbid, a destructive system crash. It's unusual, but it does work, even if it takes that little bit longer to get things sorted out when you first meet up with it.
Apart from the Apache set up and finding the right things to install, getting a test web server up and running was a fairly uneventful process. All's working well now, and I'll be taking things forward from here; making website Perl scripts compatible with their new world will be one of the next things that need to be done.