project-config/nodepool/elements/README.rst
John L. Villalovos 14e7cb3eb2 Update doc to have 'debootstrap' dep and describe minimal
Update the doc, that explains how to use disk-image-builder to create an
image, to have an additional dependency on 'debootstrap'

Also remove DISTRO= line from example as it was confusing and would make
people not build the ubuntu-minimal image.

Add a little info on the -minimal build types.

Change-Id: I8a7393a9c71ef503a730e4442941996eab43da6b
2016-10-12 19:27:05 -07:00

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Using diskimage-builder to build devstack-gate nodes
====================================================
In addition to being able to just download and consume images that are the
same as what run devstack-gate, it's easy to make your own for local dev or
testing - or just for fun.
Install diskimage-builder
-------------------------
Install the dependencies:
::
sudo apt-get install kpartx qemu-utils curl python-yaml debootstrap
Install diskimage-builder:
::
sudo -H pip install diskimage-builder
Build an image
--------------
Building an image is simple, we have a script!
::
bash tools/build-image.sh
See the script for environment variables to set distribution, etc. By default
it builds an ubuntu-minimal based image. You should be left with a .qcow2
image file of your selected distribution.
Infra uses the -minimal build type for building Ubuntu/CentOS/Fedora. For
example: ubuntu-minimal.
It is a good idea to set ``TMP_DIR`` to somewhere with plenty of space
to avoid the disappointment of a full-disk mid-way through the script
run.
While testing, consider exporting DIB_OFFLINE=true, to skip updating the cache.
Mounting the image
------------------
If you would like to examine the contents of the image, you can mount it on
a loopback device using qemu-nbd.
::
sudo apt-get install qemu-utils
sudo modprobe nbd max_part=16
sudo mkdir -p /tmp/newimage
sudo qemu-nbd -c /dev/nbd1 /path/to/devstack-gate-precise.qcow2
sudo mount /dev/nbd1p1 /tmp/newimage
or use the scripts
::
sudo apt-get install qemu-utils
sudo modprobe nbd max_part=16
sudo tools/mount-image.sh devstack-gate-precise.qcow2
sudo tools/umount-image.sh
Other things
------------
It's a qcow2 image, so you can do tons of things with it. You can upload it
to glance, you can boot it using kvm, and you can even copy it to a cloud
server, replace the contents of the server with it and kexec the new kernel.