Virtual Machine from a Hard Disk Image with virt-install --import

This is one of many ways to create a virtual machine. This way starts with a hard disk image.

NAME=sles12sp2b4
IMG=https://example.com/images/SLE_12_SP2_Beta4-x86_64-default.qcow2
wget -O /var/lib/libvirt/images/$NAME $IMG
virt-install --name $NAME \
       --ram 2048 --graphics type=vnc \
       --network bridge=br0 \
       --import \
       --disk bus=virtio,path=/var/lib/libvirt/images/$NAME

For IMG I used a SUSE-internal server with SLEnkins images.
The tricky part is knowing the right value for the --disk bus setting. At first I used the default but the machine wouldn't boot because it would see /dev/sda instead of /dev/vda it was expecting.

Ruby Call Graph

Call-graph makes a call graph among methods of a single Ruby file.
I made it to help me orient myself in unfamiliar legacy code and to help identify cohesive parts that could be split out.
Yes, it is quick and dirty.

Example

One file in YaST has around 2700 lines and 73 methods. The call graph below was made with

$ ./call-graph ../yast/packager/src/modules/Packages.rb
$ dot -Tpng -oPackages.png ../yast/packager/src/modules/Packages.dot

If the resulting size is too big, use ImageMagick:

$ convert Packages.png -resize 1200 Packages-small.png

Packages.png, an example output

Requirements

• Ruby
• parser gem
• Graphviz

License

MIT