project-config/nodepool/elements/README.rst
Ramy Asselin 0d5c572d52 Update dib script usage
Update manual dib mounting instructions to match changes made in the
tools/mount-image.sh script (I0deba1907f390f0d308ae6c8ed5448afbbf7688a)
and add a reference to the script itself in the documentation.

Change-Id: Ic72bf05f21cecb8bdff36956f3635c2f504c4dff
2015-03-10 15:58:32 -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
Install diskimage-builder:
::
sudo -H pip install diskimage-builder
Build an image
--------------
Building an image is simple, we have a script!
::
DISTRO="ubuntu" DIB_RELEASE="trusty" bash tools/build-image.sh
See the script for environment variables to set distribution, etc.
You should be left with a .qcow2 image file of your selected
distribution.
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.