Monday, November 10, 2014

Is 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 account, their is no avenue for support.

As a result, my only available course of action was to cancel my account.

Saturday, July 05, 2014

IPtables Blocking KVM Bridge

Recently, 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 RELATED,ESTABLISHED -j ACCEPT
iptables -I FORWARD -i br0 -o br0 \
  -m state --state NEW -j ACCEPT
This will allow UDP, TCP, and ICMP initiated from the physical network to be routed to VMs attached to the br0 bridge.

This configuration is that it route all traffic, which some might consider bad form. If the KVM host only ran a fixed set of VMs, it might be wise to lock down specific ports. In a dynamic environment (like my lab) the level of effort to support IPtables on the host exceeds the risk, as the VMs are all running IPtables themselves.

Monday, June 30, 2014

Auqaponic 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 might lead to total failure.

Thursday, April 17, 2014

BeagleBone Black Console Cable

I 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 "Prolific Technology PL2303" converter, and the serial header on the BeagleBone. The lack of documentation should not have been a surprise: most people have no interest in this feature.

To make matters more interesting, the picture on the Adafruit website was off by one pin. Luckily, Google Images was able to find the blog of Christophe Blaess, who had posted a picture of the correct pin-out:
The blog is written in French, which I don't speak, but a picture is worth a thousand words.

Thursday, March 13, 2014

KVM Network Bridge

Finally, a simple way to configure a bridged network for a KVM server:
virsh iface-bridge eth2 br0