tag:blogger.com,1999:blog-97578122024-03-13T02:22:47.234-04:00Doug BungerDoug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.comBlogger516125tag:blogger.com,1999:blog-9757812.post-74299832594540826692014-11-10T09:27:00.000-05:002014-11-10T09:27:46.802-05:00Is VPSLink Out of Business?Yes... From all indications, VPSLink is out of business:
* Their phones lines do not work.
* E-mails are unanswered.
* New support tickets cannot be opened.
* New forum threads cannot be created.
They will let you open a new account. They will continue to bill your credit card. If you have a functioning VM, it will continue to operate. If you have any trouble with your service or Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-83037035226866567152014-07-05T14:45:00.002-04:002014-07-05T14:46:30.845-04:00IPtables Blocking KVM BridgeRecently, I've been having problems with VM networking on RHEL KVM hosts. The initial symptom is the VM cannot get a DHCP address from the physical network, through a bridged virtual NIC. I've determined the problem is the with the FORWARD chain of IPtables.
Assuming a bridged ethernet called br0, I've added the following rules:
iptables -I FORWARD -i br0 -o br0 \
-m state --state Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-16340348195081278322014-06-30T17:53:00.000-04:002014-06-30T17:54:47.882-04:00Auqaponic System
I've constructed a small auqaponics system in my backyard green house. Here's a video of the first iteration. I have been impressed at how little water loss I'm experiencing in the system. Admittedly, the system is over-engineered, but that is normal for a prototype.
It's better to put too much into a test system, and introduce incremental cost savings over time, then to cut corners that Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-41337882723804826582014-04-17T22:21:00.003-04:002014-06-30T17:54:21.191-04:00BeagleBone Black Console CableI recently got a BeagleBone Black from Adafruit. Immediate access was easy using the USB interface:
sudo screen /dev/ttyACM0 115200
To disconnect, press [Ctrl][A], followed by [k], and respond [y].
I wanted to watch boot sequence, but the USB does not come online until the end of the init process. I had purchased a USB to serial adapter, but did not find an obvious path between the "Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-73464597730155631512014-03-13T21:12:00.002-04:002014-07-05T14:46:46.100-04:00KVM Network BridgeFinally, a simple way to configure a bridged network for a KVM server:
virsh iface-bridge eth2 br0
Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-445157215848405252013-05-27T22:48:00.001-04:002013-05-27T22:59:31.886-04:00PVM, aka Beowulf ClusterI stumbled upon a little project this weekend and found myself without a Beowulf cluster to help out. It had been several years since I'd built a computational cluster, so I noticed a few "new" gothchas. But... before we get to the fun stuff, let's review:
No, Beowulf is not "dead technology"
No, Hadoop is not the perfect tool for every job
That which was once called a Beowulf Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-62290048264779116212013-03-11T22:41:00.002-04:002013-03-11T22:41:26.368-04:00Fun with Unicode CharactersWhenever I am tasked with creating a web page, it ends up being the absolute bare minimum. (If you don't believe me, just visit dougbunger.com!) Of course I do it in the interest of fast rendering and bandwidth conservation... because I am a good Internet citizen. So here are some fun unicode graphics that can be used as web page icons. There are thousands of characters, Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-41643243268405572022013-03-06T08:11:00.000-05:002013-03-11T22:41:45.596-04:00Removing Old Linux KernelsToday, I had trouble removing an obsolete kernel from my workstation. It should have been simple enough, but I tried to use yum erase rather than rpm -e, and kept running into errors. That is obviously the bad news, so let's make sure to report the good news: YUM is such an improvement over RPM alone, that it is smart enough to know which kernels are obsolete. For instance:
# rpm -qa kernel
Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-63738206677564373412013-02-10T15:14:00.000-05:002013-02-10T15:14:28.074-05:00RHEL6 Udev RulesI recently moved my home workstation from Fedora to Scientific Linux 6, on the grounds that Fedora has diverged too far from the current RedHat distribution. Sure, bleeding edge is cool, but as a self professed Linux mercenary, I need to be in sync with what the real world is doing... not what it might be doing.
After the move, I've found myself annoyed by the way the Gnome desktop handlesDoug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-12885096957281501482013-01-15T22:13:00.000-05:002013-01-15T22:13:24.246-05:00Eclipse Plugins For RedHatYou know how they say you shouldn't look at the sun during an eclipse or you'll go blind? If there was any truth to that, why aren't there villages full of blind people in third world nations. Why aren't there myths about the time that everyone on Earth went blind? Think about it... There had to be a first eclipse. Who told the first dude not to look at it or he'd goDoug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-71789545338464581472012-12-30T21:16:00.002-05:002012-12-30T21:16:40.860-05:00Defeating Facial RecognitionI saw a web advertisement from Merrill Edge Investments (not to be confused with Merrill Lynch... a risk latent, greedy, delusional, Wall Street investment firm that helped firm cheat millions of people out of their retirement earnings) for a new investment tool called Face Retirement. The concept of the ad campaign is based on the work of Daniel Goldstein, PhD, who says people fail to Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-81824006011255474302012-12-29T20:16:00.000-05:002012-12-29T20:16:02.522-05:00No Reserved Words in XMLOr so goes the mantra, but if that's true then why can't I use this syntax:
<?xml version="1.0"?><parse> <rule id="1"> <type>pattern</type> <description>might be time value</description>
</rule>
</parse>
It passes all my tests for well formed XML.Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-54558830160833161862012-12-17T23:40:00.000-05:002012-12-17T23:41:24.981-05:00dracut: FATAL: initial SELinux policy load failedHere's an obnoxious install failure: Using the RHEL/Scientific Linux 6.3 DVD, it is possible for an install to crash on first boot with an SELinux error. The problem is a bug in the post of the target policy RPM. The bug is immediately fixed by running yum update... assuming you can figure out how to get the machine booted. Luckily, the error is nice enough to tell you how move Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-41753210654153993022012-11-22T13:14:00.000-05:002012-12-06T07:31:30.074-05:00RHEL Cluster Anti-Affinity ConfigurationI'm often amused by how vendors define "High Availability", aka HA. Customers always talk about Five Nines, but "off the shelf" HA solutions seldom achieve 99% availability. In the case of RedHat's HA cluster service, the default configuration might provide unattended failover within 60 seconds. Given that Five Nines only allows 25.9 seconds per month, a single failure can blow Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-64225337125006267822012-11-08T12:40:00.001-05:002012-11-22T13:14:36.635-05:00RHEL 6 Clustering, VM FencingI recently retasked one of my lab machines as a RedHat virtualization server, which RedHat calls RHEV, but is really KVM. One of this machine's tasks is to support a test cluster of VMs. Under normal circumstances, clustering would require a remote management interface such as an ILO, DRAC, or RMM.
As usual, I was disappointed with how difficult this was. To make matters more Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-69666722265252216732012-11-04T19:08:00.000-05:002012-11-22T13:15:30.211-05:00Kickstart from Hard Drive ISOI'm building a machine that may need to be remotely re-imaged, without the benefit a kickstart server. I've always heard that you can kick a machine from itself, but had never tried it. Truthfully, it's probably more trouble than its worth. The best option would be to install a DVD drive with media, but configure the BIOS such that DVD is after the main drive. Since I Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-52437269556302871862012-11-03T23:31:00.000-04:002012-11-03T23:31:07.924-04:00Citrix Xenserver: Apply Multiple UpdatesAs a result of reorganizing the servers in my lab, I had to reinstall Citrix Xenserver. I should have downloaded 6.1, but decided to keep it at 6.0 and apply the updates that I already had on the NAS. All went well with the install, I moved all my VMs and templates to this machine, and retasked the other machine.
When I went to load the updates, a funny thing happened... It refused Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com3tag:blogger.com,1999:blog-9757812.post-11308544233555048902012-10-23T21:08:00.002-04:002012-10-23T21:08:50.962-04:00Linux KVM Disk DriversI was having a problem with storage device names on virtual machines running on a RedHat KVM host. Occasionally, I'd build a VM and the storage device would be named /dev/sda and other times /dev/xvda. I quickly found that if I created the VM using virt-install, I got a xvda device, and if I used virt-manager (the GUI app), I got the sda device. After some investigation, I've Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-43031066368211703302012-10-23T14:34:00.000-04:002012-10-23T20:29:35.482-04:00Kitchen is Getting Close
Got the cabinets-- waiting on the counter top.
Turns out installation was not included with the vent hood, like that makes sense. What's that you say? "Nickel and dime"? Yep.Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-48215959643653431452012-10-07T20:51:00.001-04:002012-10-07T20:51:46.736-04:00Certified Ethical HackerI recently took the Certified Ethical Hacker (CEH) class and certification exam. First, I passed. Second, I was a little disappointed with the class.
Let's take a look at the first item: I passed the test. How can anyone reasonably complain about passing a certification test? Let me contrast the certification test with three other tests.
RedHat certification tests Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-84190103695199806752012-10-07T16:14:00.001-04:002012-10-07T20:58:44.641-04:00Tracking SSH TunnelsNative to Secure Shell (SSH) is the ability to create point-to-point, encrypted, tunnels. The function was designed to provide legacy protocols, such as mail (SMTP/POP) with encryption. A user could login to an SSH server in their company's DMZ, open a tunnel from their laptop to the server, and redirect their mail client through the tunnel. On the surface, this sounds like a Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-11211066002389643332012-09-01T15:09:00.000-04:002012-09-02T00:02:35.681-04:00Good news, bad newsFirst, the good news: the ceiling is fixed...
..and the floor is done.
The bad news? Still no kitchen.
And on a side note, ML asked if any of the walls I knocked out were "load bearing". So far, it seems not. I guess that's good news too!Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-53387170078757904262012-08-08T21:15:00.000-04:002012-08-08T21:15:18.641-04:00The Peter PrincipleEverybody knows The Peter Principle as "people get promoted to their level of incompetence."
Unfortunately, that's wrong.
The Peter Principle is the title of a book published in 1969, by Dr Laurence J Peter and Raymond Hull. Dr Peter did the research, Hull ghost wrote book. I recently picked up a copy from The Book Thing free store in Baltimore, that was printed in 1970. The Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-92114945873368155722012-07-24T22:52:00.002-04:002012-07-24T22:52:43.190-04:00Stupid Yahoo Password CriteriaFor about a week, I've been wrestling with my Yahoo! password. My old, but still functional, Palm Centro mobile phone has an app to connect to Yahoo mail, but it recently stopped working. Given that it failed the day after I changed my password, one might claim that it was a self inflicted injury, but no... it was Yahoo's fault for storing 450,000 passwords in clear text which, Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com0tag:blogger.com,1999:blog-9757812.post-64191340734281184082012-07-06T10:34:00.000-04:002012-12-26T21:44:36.504-05:00Use awk To grep "this but not that"I've run into this situation several times over the decades, bit for some reason I never researched an elegant solution. Consider the case of grep'ing to see if a process is running. The simple solution is:
ps -ef | grep "ntpd"
The problem is that if there is one process matching the regex, this will report two processes, because it will also report the grep process that is grep'ing the Doug Bungerhttp://www.blogger.com/profile/13269100153041644287noreply@blogger.com2