Easy headless KVM deployment with virt-install

I’d like for the VMs I’m deploying to be entirely headless (that is, no virtual graphics card at all, serial console only).  Turns out that you can do ISO-based installations of CentOS-7, headless, without having to unpack the ISO and mess with stuff.  Enter virt-install, the swiss army knife of KVM O/S installs;

Read More

TRIM Support on KVM Virtual Machines

Messing with KVM as a replacement for my Microserver setup at home.  With KVM, you can define a thin-provisioned VM image file (a qcow2 file), which is a sparse file on the filesystem.  You can then configure the guest O/S so that TRIM support works, and it can then unmap unused blocks by the guest FS and have those blocks get unmapped the whole way down the stack (released from the sparse file, and ultimately trimmed from the underlying SSD if there is one).

Read More

ESP8266 Environment Widget – Software

Last post I mentioned how I got an ESP8266 board.  Well, I’ve put together that with a DHT11 and MQTT to create a widget that senses temperature and humidity, then posts that on a regular basis to your MQTT message broker.  The data comes out in JSON format for ease of use.  I’ll cover the hardware later, once I get the rest of my prototype boards.

Read More