Installing Xen on Fedora 20

Xen LogoI’ve written about installing Xen on Fedora 19 and earlier versions on this blog before. Let’s tackle it on Fedora 20.

Start with the Xen hypervisor and the basic toolset first:

yum -y install xen xen-hypervisor xen-libs xen-runtime
systemctl enable xend.service
systemctl enable xendomains.service

Get GRUB2 in order:

# grep ^menuentry /boot/grub2/grub.cfg | cut -d "'" -f2
Fedora, with Linux 3.13.4-200.fc20.x86_64
Fedora, with Linux 0-rescue-c9dcecb251df472fbc8b4e620a749f6d
Fedora, with Xen hypervisor
# grub2-set-default 'Fedora, with Xen hypervisor'
# grub2-editenv list
saved_entry=Fedora, with Xen hypervisor
# grub2-mkconfig -o /boot/grub/grub.cfg

Now reboot. When the server restarts, verify that Xen is running:

# xm dmesg | head
 __  __            _  _    _____  _    ___    __      ____   ___  
 \ \/ /___ _ __   | || |  |___ / / |  / _ \  / _| ___|___ \ / _ \ 
  \  // _ \ '_ \  | || |_   |_ \ | |_| (_) || |_ / __| __) | | | |
  /  \  __/ | | | |__   _| ___) || |__\__, ||  _| (__ / __/| |_| |
 /_/\_\___|_| |_|    |_|(_)____(_)_|    /_(_)_|  \___|_____|\___/ 
 
(XEN) Xen version 4.3.1 (mockbuild@[unknown]) (gcc (GCC) 4.8.2 20131212 (Red Hat 4.8.2-7)) debug=n Thu Feb  6 16:52:58 UTC 2014
(XEN) Latest ChangeSet: 
(XEN) Bootloader: GRUB 2.00
(XEN) Command line: placeholder

As I’ve mentioned before, I enjoy using virt-manager to manage my VM’s. Let’s get started:

yum -y install virt-manager dejavu* xorg-x11-xauth
yum -y install libvirt-daemon-driver-network libvirt-daemon-driver-storage libvirt-daemon-xen
systemctl enable libvirtd.service
systemctl start libvirtd.service

By this point, you have the Xen hypervisor running and you have VM management tools available from virt-manager and libvirt. Enjoy!

icanhaz more domains: icanhazepoch.com

Sometimes I can’t help myself. I like to buy domains and use them for interesting activities. This tweet cropped up in my stream tonight:

You can give it a try now: icanhazepoch.com

$ curl icanhazepoch.com
1393036551

I’m doing my best to keep the server time in sync, so it should be relatively reliable. However, I wouldn’t recommend using it for launching satellites or timing anything where someone’s life is held in the balance. If you don’t know why this warning is here, read up on NTP jitter.

Thanks to @claco for the idea and to Namecheap for fueling my domain purchasing addiction.

MySQLTuner v1.3.0

It’s been three long years since the last MySQLTuner release but you’ll now find version 1.3.0 available on GitHub. You can get it from the git repository or via these extremely simple methods:

wget -O mysqltuner.pl mysqltuner.pl
wget --trust-server-names mysqltuner.pl

There are a bunch of new features and fixes that you can find in the list of commits from today (2014-02-21). Some of the bigger adjustments include:

  • Basic support for MariaDB 10.x
  • A more flexible storage engine display
  • Better support for darwin, solaris, and BSD variants
  • Version checking is removed until I can find a better method
  • Fixed a divide by zero error with a key_buffer_size set to 0
  • Custom paths to mysqladmin are now supported with a command line parameter

I’d still like to convert this script over to python and make it installable from pypi. That’s a work in progress.

Puppy Linux, icanhazip, and tin foil hats

I figured that the Puppy Linux and icanhazip.com fiasco was over, but I was wrong:

After a quick visit to the forums, I found the debate stirred up again. Various users were wondering if their internet connections were somehow compromised or if a remote American network was somehow spying on their internet traffic. Others wondered if some secretive software was added to the Puppy Linux distribution that was calling out to the site.

Fortunately, quite a few users on the forum showed up to explain that Puppy Linux has a built-in feature to figure out a user’s external IP address to help them get started with their system after it boots. Another user was kind enough to dig up the Lifehacker post about icanhazip from 2011.

Many users on the forum were still dissatisfied. Many of them turned their questions to maintainers of the distribution (which is where those questions should go), but many others felt that icanhazip was the source of the problem. Some of them felt so strongly that they called my hosting provider via telephone to curse at them. Here’s a snippet of an email I received from my colocation provider:

I had an interesting call from someone today said that 216.69.252.101 was showing up on his computer. Sounded kind of [omitted] and called me a **** ******…

Let’s get three things straight:

  1. I’m a huge supporter of everything Linux, including Puppy Linux. I don’t hold a grudge against the project for what a minority of their users do.
  2. I don’t collect data when users visit icanhazip.com other than standard Apache logs. No cookies are used.
  3. I run these applications on my own time, with my own money, and my own resources.

Before I forget, thanks to all of the folks who came forward in the forums to explain what was actually happening and defend the work I’ve done. I’m tremendously flattered to receive that kind of support.

Be an inspiration, not an impostor

Many of the non-technical posts on the blog are inspired by the comments of others. I stumbled upon this tweet after it was retweeted by someone I follow:

The link in the tweet takes you to a blog post from Erika Owens about impostor syndrome. Erika touches on that uncomfortable feeling that some of us feel when we’re surrounded by other people from our field of study or work. These three sentences hit home for me:

At first, I thought people were just being modest. But it soon became clear that people were reluctant to recognize in themselves the same traits that awed them in other people. This dynamic holds people back while also overtaxing the limited number of anointed experts.

Anne Gentle gave a presentation at this year’s offsite for leaders at Rackspace and talked about the challenges of defeating impostor syndrome while attending male-dominated technical conferences. She talked about a portion of these challenges in her Women of OpenStack post.

I’ve struggled with this from time to time with various groups. Sure, I have some deep technical knowledge and experience in some areas, but I don’t always feel like the expert in those areas. One thing I’ve come to realize is that when you’re invited to talk to a group or asked to write an article, you’re being asked because the community has identified you as an expert.

“Expert” is always a relative term. Toss me in a room with Windows system administrators and I can provide an expert level of guidance around the Linux kernel. If Linus or Greg Kroah-Hartman walk in the door, I’d certainly defer to them. I’d definitely offer up an opinion if asked or if I disagreed with something that was being said (even if an “expert” said it). With that said, I’ve spoken with Linus and Greg in person and they seem to understand this well. They leave gaps in conversation and defer to their peers to ensure that the experts around them get time in the spotlight.

Here’s where the rubber meets the road: when you embrace your expertise and share it with others, you inspire them.

What happens when you inspire others? They’re more eager to talk. They’re more eager to listen. They’re more eager to learn more and embrace their inner expert.

This process isn’t easy. Read through my post on why technical people should blog, but don’t. You’ll need to understand that you’ll be wrong from time to time and that you’ll need to do some homework when you’re asked for an expert opinion. You’ll also need to learn when and how to say “I don’t know, but I’ll find out the answer.”

The next time you feel like you know less than the other people in the room, speak up. You’ll probably be an inspiration to many in the room who feel like an impostor and they’ll want to follow your lead.