Tuesday, September 27, 2011

Good-bye Gnome

In the latest machine re-org, I reloaded my workstation with Fedora 15. I don't like it. I think they've made several wrong turns, the single biggest being their implementation of Gnome 3.

With Gnome 3, they have set a minimum acceptable video hardware platform. That's fine, because they provided a fallback mode in case the machine does not support 3D rendering. Accept for one minor problem... most of the desktop's features do not work in fallback mode.

For instance... The ability to exit the GUI. Yes: there is no logout, quit, exit, stop, leave, or otherwise feature. The only way out is to open a terminal and init 3. If they missed something as important as an exit function, just image what else they missed. (Hint: allot!)

So, I'm trying to switch to KDE and it looks promising. As a matter of fact, I have found a fix for my single biggest complaint with KDE. I am so use to highlighting text in a terminal window and pressing "Shift-Insert", that for five years, I have refused to use KDE because it required the extra step of "Ctrl-Insert".

On the taskbar, near the clock is a scissors icon. Left click, select Configure Klipper, and click "Synchronize contents of the clipboard and the selection". Now it works the way I want!

Monday, September 12, 2011

VM Autostart on XenServer

Its a good thing I don't need to run VMware, because they are so dependent on a pre-existing Microsoft infrastructure, that I couldn't run it, even if I tried. And I've tried. Of course, I should just go ahead and invest the $3,000 in Microsoft software... just so I can invest a $1,000 in VMware software. Or, I could use Citrix XenServer.

Unfortunately, Citrix is doing everything in their power to ruin their entry level product, based on the philosophy that if they strip enough useful features from their product, eventually people will have no choice but to buy it. I don't know... If I'm going to throw two grand at them, I might as well up the ante and buy VMware.

Or just hack their product. I mean, come on guys... are you even trying?

So, I've got a cluster of XenServers, and I want to start a VM with the host boots. Ah! Upgrade XenServer to enable! Or add the following to the /etc/rc.d/rc.local for all hosts:
xe vm-start name-lable=YourVmName
If the host is the first to boot, it starts the VM. If the host is not the first, it attempts the command, gets a failure message (becuase the VM is in the wrong power state... on), and boots as normal.

And now we give thanks to the command line Gods.

Wednesday, September 07, 2011

Linux Rescue for VM on XenServer

I finally figured out how to rescue a Linux VM running on a Citrix XenServer host, an believe it or not, it is completely unintuitive! First, power off the VM, though if you're going to rescue mode... you're probably "down" already. Second, mount the rescue media (CD/DVD). Third, make sure the VM is highlighted on the left pane of XenCenter.

Here's the trick: Across the top of the XenCenter menu, select VM, and Start/Shut down, and Start in Recovery Mode. The machine should boot from the rescue media. Proceed per rescue SOP.

Be forewarned... For some reason, booting is incredibly slow.

Monday, September 05, 2011

SSH Tunneliung of X11 Apps

I had occasion to finally test something I've been wondering for a while: What is the minimal configuration to allow and X11 application to tunnel through SSH? First, this procedure assumes you have a workstation that can display X11 applications. This can either be a Linux desktop or a Windows machine running Xming or another lesser X client.

Second, install a system with only the core or base packages, possibly by building the system through kickstart. Third, edit the /etc/ssh/sshd_config and make sure X11Forwarding is set to yes. Reload if needed.

Next install a simple graphical application; for my test I used xclock:
yum install -y xorg-x11-apps
Attempt to run:
ssh -X xclock
Error: Can't open display
In this case a failure is what we expect.

Conventional wisdom says we need to install the entire "X11 Window System" group, which will grab almost 100 packages. Instead install one RPM:
yum install -y xorg-x11-xauth
ssh -X xclock

Warning: <snip> (repeated several times)
...but behold! A glorious xclock. The errors are from not loading fonts on the remote machine. Oddly, if we install xterm, it also complains, yet it works just fine.

A side note on this procedure: To prevent from issuing the -X (or -Y) with the SSH command line, change /etc/ssh/ssh_config, adding:
ForwardX11 yes

Adding gedit will require 57 more packages.
Adding kedit will require 68 more packages.
Best choice: gvim, requiring three packages.
yum install -y xorg-x11-fonts-Type1 xorg-x11-fonts-misc
yum install -y gvim

Saturday, September 03, 2011

Rubus Cabernet Sauvignon

From the back label: "flavors of blackberry, currant, and chocolate"... unfortunately, I'm allergic to blackberry and currant. It took several years of research, but my very unscientific explanation is that blackberries, grapes, and blueberries are all related. They all grow on vines, but grapes and blueberries are smooth, but blackberries (and raspberries) are "bumpy". I'm allergic to bumpy berries.

In the universal order of things, some grapes are closer to blackberries and some are closer to blueberries. Currants are smooth, but fall right between the blackberries and grapes. As such, any wine that describes itself as tasting of currants and blackberries will cause my throat to swell, and I'll choke and cough. Cabernet Sauvignon is such a wine.

So why would I buy a bottle of wine with the potential of choking me to death? I didn't, my son the chef bought this, not knowing the potential side effects. Of course I drank it anyway.

Once you discount the likelihood of a slow an torturous demise, he actually did a good job. He picked an older wine, a 2007, specifically claiming to be "old vine" grapes. The older the vines, the deeper the root system, and the more stable the flavor. The wine had good body and flavor, but I can only give it a 4 out of 10, on the grounds that I wouldn't chance it again.