Faster rebuilds for python virtualenv trees

Posted: November 14th, 2014 | Author: | Filed under: Coding Tips, Fedora, OpenStack, Virt Tools | Tags: , , , , , , | 5 Comments »

When developing on OpenStack, it is standard practice for the unit test suites to be run in a python virtualenv. With the Nova project at least, and I suspect most others too, setting up the virtualenv takes a significant amount of time as there are many packages to pull down from PyPI, quite a few of which need compilation too. Any time the local requirements.txt or test-requirements.txt files change it is necessary to the rebuild the virtualenv. This rebuild is an all-or-nothing kind of task, so can be a significant time sink, particularly if you frequently jump between different code branches.

At the OpenStack design summit in Paris, Joe Gordon showed Matt Booth how to setup devpi and wheel to provide a cache of the packages that make up the virtualenv. Not only does it avoid the need to repeatedly download the same packages from pypi each time, but it also avoids the compilation step, since the cache is storing the final installed pieces for each python module. The end result is that it takes 20-30 seconds or less to rebuild a virtualenv instead of many minutes.

After a few painful waits for virtualenvs today, I decided to set it up too I don’t like installing non-packaged software as root on my machines, so what follows is all done as a regular user account. The first step is to pull down the devpi and wheel packages from pypi, telling pip to install them in under $HOME/.local

# pip install --user devpi
# pip install --user wheel

Since we’re using a custom install location, it necessary to update your $HOME/.bashrc file with new $PATH and $PYTHONPATH environment variables and then source the .bashrc file

# cat >> $HOME/.bashrc <<EOF
export PATH=\$PATH:$HOME/.local/bin
export PYTHONPATH=$HOME/.local/lib/python2.7/site-packages
EOF
# . $HOME/.bashrc

The devpi package provides a local server that will be used for downloads instead of directly accessing pypi.python.org, so this must be started

# devpi-server --start

Both devpi and wheel integrate with pip, so the next setup task is to modify the pip configuration file

# cat >> $HOME/.pip/pip.conf <<EOF
[global]
index-url = http://localhost:3141/root/pypi/+simple/
wheel-dir = /home/berrange/.pip/wheelhouse
find-links = /home/berrange/.pip/wheelhouse
EOF

We’re pretty much done at this point – all that is left is to prime the cache with the all the packages that Nova wants to use

# cd $HOME/src/cloud/nova
# pip wheel -r requirements.txt
# pip wheel -r test-requirements.txt

Now if you run any command that would build a Nova virtualenv, you should notice it is massively faster

# tox -e py27
# ./run_tests.sh -V

That is basically all there is to it. Blow away the virtualenv directories at any time and they’ll be repopulated from the cache. If the requirements.txt is updated with new deps re-running the ‘pip wheel’ command above will update the cache to hold the new bits.

That was all incredibly easy and so I’d highly recommend devs on any non-trivially sized python project make use of it.  Thanks to Joe Gordon for the pointing this out at the summit !

What DevStack does to your host when setting up OpenStack on Fedora 17

Posted: November 20th, 2012 | Author: | Filed under: Fedora, libvirt, OpenStack, Virt Tools | Tags: , , , , , , , | 2 Comments »

As I mentioned in my previous post, I’m not really a fan of giant shell scripts which ask for unrestricted sudo access without telling you what they’re going todo. Unfortunately DevStack is one such script :-( So I decided to investigate just what it does to a Fedora 17 host when it is run. The general idea I had was

  • Install a generic Fedora 17 guest
  • Create a QCow2 image using the installed image as its backing file
  • Reconfigure the guest to use the QCow2 image as its disk
  • Run DevStack in the guest
  • Compare the contents of the original installed image and the DevStack processed image

It sounded like libguestfs ought to be able to help out with the last step, and after a few words with Rich, I learnt about use of virt-ls for exactly this purpose. After trying this once, it quickly became apparent that just comparing the lists of files is quite difficult because DevStack installs a load of extra RPMs with many 1000’s of files. So to take this out of the equation, I grabbed the /var/log/yum.log file to get a list of all RPMs that DevStack had installed, and manually added them into the generic Fedora 17 guest base image. Now I could re-run DevStack again and do a file comparison which excluded all the stuff installed by RPM.

RPM packages installed (with YUM)

  • apr-1.4.6-1.fc17.x86_64
  • apr-util-1.4.1-2.fc17.x86_64
  • apr-util-ldap-1.4.1-2.fc17.x86_64
  • augeas-libs-0.10.0-3.fc17.x86_64
  • binutils-2.22.52.0.1-10.fc17.x86_64
  • boost-1.48.0-13.fc17.x86_64
  • boost-chrono-1.48.0-13.fc17.x86_64
  • boost-date-time-1.48.0-13.fc17.x86_64
  • boost-filesystem-1.48.0-13.fc17.x86_64
  • boost-graph-1.48.0-13.fc17.x86_64
  • boost-iostreams-1.48.0-13.fc17.x86_64
  • boost-locale-1.48.0-13.fc17.x86_64
  • boost-program-options-1.48.0-13.fc17.x86_64
  • boost-python-1.48.0-13.fc17.x86_64
  • boost-random-1.48.0-13.fc17.x86_64
  • boost-regex-1.48.0-13.fc17.x86_64
  • boost-serialization-1.48.0-13.fc17.x86_64
  • boost-signals-1.48.0-13.fc17.x86_64
  • boost-system-1.48.0-13.fc17.x86_64
  • boost-test-1.48.0-13.fc17.x86_64
  • boost-thread-1.48.0-13.fc17.x86_64
  • boost-timer-1.48.0-13.fc17.x86_64
  • boost-wave-1.48.0-13.fc17.x86_64
  • ceph-0.44-5.fc17.x86_64
  • check-0.9.8-5.fc17.x86_64
  • cloog-ppl-0.15.11-3.fc17.1.x86_64
  • cpp-4.7.2-2.fc17.x86_64
  • curl-7.24.0-5.fc17.x86_64
  • Django-1.4.2-1.fc17.noarch
  • django-registration-0.7-3.fc17.noarch
  • dmidecode-2.11-8.fc17.x86_64
  • dnsmasq-utils-2.63-1.fc17.x86_64
  • ebtables-2.0.10-5.fc17.x86_64
  • euca2ools-2.1.1-2.fc17.noarch
  • gawk-4.0.1-1.fc17.x86_64
  • gcc-4.7.2-2.fc17.x86_64
  • genisoimage-1.1.11-14.fc17.x86_64
  • git-1.7.11.7-1.fc17.x86_64
  • glusterfs-3.2.7-2.fc17.x86_64
  • glusterfs-fuse-3.2.7-2.fc17.x86_64
  • gnutls-utils-2.12.17-1.fc17.x86_64
  • gperftools-libs-2.0-5.fc17.x86_64
  • httpd-2.2.22-4.fc17.x86_64
  • httpd-tools-2.2.22-4.fc17.x86_64
  • iptables-1.4.14-2.fc17.x86_64
  • ipxe-roms-qemu-20120328-1.gitaac9718.fc17.noarch
  • iscsi-initiator-utils-6.2.0.872-18.fc17.x86_64
  • kernel-headers-3.6.6-1.fc17.x86_64
  • kpartx-0.4.9-26.fc17.x86_64
  • libaio-0.3.109-5.fc17.x86_64
  • libcurl-7.24.0-5.fc17.x86_64
  • libmpc-0.9-2.fc17.2.x86_64
  • libunwind-1.0.1-3.fc17.x86_64
  • libusal-1.1.11-14.fc17.x86_64
  • libvirt-0.9.11.7-1.fc17.x86_64
  • libvirt-client-0.9.11.7-1.fc17.x86_64
  • libvirt-daemon-0.9.11.7-1.fc17.x86_64
  • libvirt-daemon-config-network-0.9.11.7-1.fc17.x86_64
  • libvirt-daemon-config-nwfilter-0.9.11.7-1.fc17.x86_64
  • libvirt-python-0.9.11.7-1.fc17.x86_64
  • libwsman1-2.2.7-5.fc17.x86_64
  • lzop-1.03-4.fc17.x86_64
  • m2crypto-0.21.1-8.fc17.x86_64
  • mod_wsgi-3.3-2.fc17.x86_64
  • mx-3.2.3-1.fc17.x86_64
  • mysql-5.5.28-1.fc17.x86_64
  • mysql-libs-5.5.28-1.fc17.x86_64
  • MySQL-python-1.2.3-5.fc17.x86_64
  • mysql-server-5.5.28-1.fc17.x86_64
  • netcf-libs-0.2.2-1.fc17.x86_64
  • numad-0.5-4.20120522git.fc17.x86_64
  • numpy-1.6.2-1.fc17.x86_64
  • parted-3.0-10.fc17.x86_64
  • perl-AnyEvent-5.27-7.fc17.noarch
  • perl-AnyEvent-AIO-1.1-8.fc17.noarch
  • perl-AnyEvent-BDB-1.1-7.fc17.noarch
  • perl-Async-MergePoint-0.03-7.fc17.noarch
  • perl-BDB-1.88-5.fc17.x86_64
  • perl-common-sense-3.5-1.fc17.noarch
  • perl-Compress-Raw-Bzip2-2.052-1.fc17.x86_64
  • perl-Compress-Raw-Zlib-2.052-1.fc17.x86_64
  • perl-Config-General-2.50-6.fc17.noarch
  • perl-Coro-6.07-3.fc17.x86_64
  • perl-Curses-1.28-5.fc17.x86_64
  • perl-DBD-MySQL-4.020-2.fc17.x86_64
  • perl-DBI-1.617-1.fc17.x86_64
  • perl-Encode-Locale-1.02-5.fc17.noarch
  • perl-Error-0.17016-7.fc17.noarch
  • perl-EV-4.03-8.fc17.x86_64
  • perl-Event-1.20-1.fc17.x86_64
  • perl-Event-Lib-1.03-16.fc17.x86_64
  • perl-Git-1.7.11.7-1.fc17.noarch
  • perl-Glib-1.241-2.fc17.x86_64
  • perl-Guard-1.022-1.fc17.x86_64
  • perl-Heap-0.80-10.fc17.noarch
  • perl-HTML-Parser-3.69-3.fc17.x86_64
  • perl-HTML-Tagset-3.20-10.fc17.noarch
  • perl-HTTP-Date-6.00-3.fc17.noarch
  • perl-HTTP-Message-6.03-1.fc17.noarch
  • perl-IO-AIO-4.15-1.fc17.x86_64
  • perl-IO-Async-0.29-7.fc17.noarch
  • perl-IO-Compress-2.052-1.fc17.noarch
  • perl-IO-Socket-SSL-1.66-1.fc17.noarch
  • perl-IO-Tty-1.10-5.fc17.x86_64
  • perl-LWP-MediaTypes-6.01-4.fc17.noarch
  • perl-Net-HTTP-6.02-2.fc17.noarch
  • perl-Net-LibIDN-0.12-8.fc17.x86_64
  • perl-Net-SSLeay-1.48-1.fc17.x86_64
  • perl-POE-1.350-2.fc17.noarch
  • perl-Socket6-0.23-8.fc17.x86_64
  • perl-Socket-GetAddrInfo-0.19-1.fc17.x86_64
  • perl-TermReadKey-2.30-14.fc17.x86_64
  • perl-TimeDate-1.20-6.fc17.noarch
  • perl-URI-1.60-1.fc17.noarch
  • ppl-0.11.2-8.fc17.x86_64
  • ppl-pwl-0.11.2-8.fc17.x86_64
  • pylint-0.25.1-1.fc17.noarch
  • python-amqplib-1.0.2-3.fc17.noarch
  • python-anyjson-0.3.1-3.fc17.noarch
  • python-babel-0.9.6-3.fc17.noarch
  • python-BeautifulSoup-3.2.1-3.fc17.noarch
  • python-boto-2.5.2-1.fc17.noarch
  • python-carrot-0.10.7-4.fc17.noarch
  • python-cheetah-2.4.4-2.fc17.x86_64
  • python-cherrypy-3.2.2-1.fc17.noarch
  • python-coverage-3.5.1-0.3.b1.fc17.x86_64
  • python-crypto-2.6-1.fc17.x86_64
  • python-dateutil-1.5-3.fc17.noarch
  • python-devel-2.7.3-7.2.fc17.x86_64
  • python-docutils-0.8.1-3.fc17.noarch
  • python-eventlet-0.9.17-1.fc17.noarch
  • python-feedparser-5.1.2-2.fc17.noarch
  • python-gflags-1.5.1-2.fc17.noarch
  • python-greenlet-0.3.1-11.fc17.x86_64
  • python-httplib2-0.7.4-6.fc17.noarch
  • python-iso8601-0.1.4-4.fc17.noarch
  • python-jinja2-2.6-2.fc17.noarch
  • python-kombu-1.1.3-2.fc17.noarch
  • python-lockfile-0.9.1-2.fc17.noarch
  • python-logilab-astng-0.23.1-1.fc17.noarch
  • python-logilab-common-0.57.1-2.fc17.noarch
  • python-lxml-2.3.5-1.fc17.x86_64
  • python-markdown-2.1.1-1.fc17.noarch
  • python-migrate-0.7.2-2.fc17.noarch
  • python-mox-0.5.3-4.fc17.noarch
  • python-netaddr-0.7.5-4.fc17.noarch
  • python-nose-1.1.2-2.fc17.noarch
  • python-paramiko-1.7.7.1-2.fc17.noarch
  • python-paste-deploy-1.5.0-4.fc17.noarch
  • python-paste-script-1.7.5-4.fc17.noarch
  • python-pep8-1.0.1-1.fc17.noarch
  • python-pip-1.0.2-2.fc17.noarch
  • python-pygments-1.4-4.fc17.noarch
  • python-qpid-0.18-1.fc17.noarch
  • python-routes-1.12.3-3.fc17.noarch
  • python-setuptools-0.6.27-2.fc17.noarch
  • python-sphinx-1.1.3-1.fc17.noarch
  • python-sqlalchemy-0.7.9-1.fc17.x86_64
  • python-suds-0.4.1-2.fc17.noarch
  • python-tempita-0.5.1-1.fc17.noarch
  • python-unittest2-0.5.1-3.fc17.noarch
  • python-virtualenv-1.7.1.2-2.fc17.noarch
  • python-webob-1.1.1-2.fc17.noarch
  • python-wsgiref-0.1.2-8.fc17.noarch
  • pyxattr-0.5.1-1.fc17.x86_64
  • PyYAML-3.10-3.fc17.x86_64
  • qemu-common-1.0.1-2.fc17.x86_64
  • qemu-img-1.0.1-2.fc17.x86_64
  • qemu-system-x86-1.0.1-2.fc17.x86_64
  • qpid-cpp-client-0.18-5.fc17.x86_64
  • qpid-cpp-server-0.18-5.fc17.x86_64
  • radvd-1.8.5-3.fc17.x86_64
  • screen-4.1.0-0.9.20120314git3c2946.fc17.x86_64
  • scsi-target-utils-1.0.24-6.fc17.x86_64
  • seabios-bin-1.7.1-1.fc17.noarch
  • sg3_utils-1.31-2.fc17.x86_64
  • sgabios-bin-0-0.20110622SVN.fc17.noarch
  • spice-server-0.10.1-5.fc17.x86_64
  • sqlite-3.7.11-3.fc17.x86_64
  • tcpdump-4.2.1-3.fc17.x86_64
  • vgabios-0.6c-4.fc17.noarch
  • wget-1.13.4-7.fc17.x86_64
  • xen-libs-4.1.3-5.fc17.x86_64
  • xen-licenses-4.1.3-5.fc17.x86_64

Python packages installed (with PIP)

These all ended up in /usr/lib/python2.7/site-packages :-(

  • WebOp
  • amqplib
  • boto (splattering over existing boto RPM package with older version)
  • cinderclient
  • cliff
  • cmd2
  • compressor
  • django_appconf
  • django_compressor
  • django_openstack_auth
  • glance
  • horizon
  • jsonschema
  • keyring
  • keystoneclient
  • kombu
  • lockfile
  • nova
  • openstack_auth
  • pam
  • passlib
  • prettytable
  • pyparsing
  • python-cinderclient
  • python-glanceclient
  • python-novaclient
  • python-openstackclient
  • python-quantumclient
  • python-swiftclient
  • pytz
  • quantumclient
  • suds
  • swiftclient
  • warlock
  • webob

Files changed

  • /etc/group (added $USER to ‘libvirtd’ group)
  • /etc/gshadow (as above)
  • /etc/httpd/conf/httpd.conf (changes Listen 80 to Listen 0.0.0.0:80)
  • /usr/lib/python2.7/site-packages/boto (due to overwriting RPM provided boto)
  • /usr/bin/cq (as above)
  • /usr/bin/elbadmin (as above)
  • /usr/bin/list_instances (as above)
  • /usr/bin/lss3 (as above)
  • /usr/bin/route53 (as above)
  • /usr/bin/s3multiput (as above)
  • /usr/bin/s3put (as above)
  • /usr/bin/sdbadmin (as above)

Files created

  • /etc/cinder/*
  • /etc/glance/*
  • /etc/keystone/*
  • /etc/nova/*
  • /etc/httpd/conf.d/horizon.conf
  • /etc/polkit-1/localauthority/50-local.d/50-libvirt-reomte-access.pkla
  • /etc/sudoers.d/50_stack_sh
  • /etc/sudoers.d/cinder-rootwrap
  • /etc/sudoers.d/nova-rootwrap
  • $DEST/cinder/*
  • $DEST/data/*
  • $DEST/glance/*
  • $DEST/horizon/*
  • $DEST/keystone/*
  • $DEST/noVNC/*
  • $DEST/nova/*
  • $DEST/python-cinderclient/*
  • $DEST/python-glanceclient/*
  • $DEST/python-keystoneclient/*
  • $DEST/python-novaclient/*
  • $DEST/python-openstackclient/*
  • /usr/bin/cinder*
  • /usr/bin/glance*
  • /usr/bin/keystone*
  • /usr/bin/nova*
  • /usr/bin/openstack
  • /usr/bin/quantum
  • /usr/bin/swift
  • /var/cache/cinder/*
  • /var/cache/glance/*
  • /var/cache/keystone/*
  • /var/cache/nova/*
  • /var/lib/mysql/cinder/*
  • /var/lib/mysql/glance/*
  • /var/lib/mysql/keystone/*
  • /var/lib/mysql/mysql/*
  • /var/lib/mysql/nova/*
  • /var/lib/mysql/performance_schema/*

Thoughts on installation

As we can see from the details above, DevStack does a very significant amount of work as root using sudo. I had fully expected that it was installing RPMs as root, but I had not counted on it adding extra python modules into /usr/lib/python-2.7, nor the addition of files in /etc/, /var or /usr/bin. I had set the $DEST environment variable for DevStack naively assuming that it would cause it to install everything possible under that location. In fact the $DEST variable was only used to control where the GIT checkouts of each openstack component went, along with a few misc files in $DEST/files/

IMHO a development environment setup tool should do as little as humanely possible as root. From the above list of changes, the only things that I believe justify use of sudo privileges are:

  • Installation of RPMs from standard YUM repositories
  • Installation of /etc/sudoers.d/ config files
  • Installation of /etc/polkit file to grant access to libvirtd

Everything else is capable of being 100% isolated from the rest of the OS, under the $DEST directory location. Taking that into account my preferred development setup would be

$DEST
 +- nova (GIT checkout)
 +- ...etc... (GIT checkout)
 +- vroot
     +- bin
     |   +- nova
     |   +- ...etc...
     +- etc
     |   +- nova
     |   +- ...etc...
     +- lib
     |   +- python2.7
     |       +- site-packages
     |           +- boto
     |           +- ...etc...
     +- var
         +- cache
         |   +- nova
         |   +- ...etc...
         +- lib
             +- mysql

This would imply running a private copy of qpid, mysql and httpd, ideally all inside the same screen session as the rest of the OpenStack services, using unprivileged ports. Even if we relied on the system instances of qpid, mysql, httpd and did a little bit more privileged config, 95% of the rest of the stuff DevStack does as root, could still be kept unprivileged. I am also aware that current OpenStack code may not be amenable to installation in locations outside of / by default, but the code is all there to be modified to cope with arbitrary install locations if desired/required.

My other wishlist item for DevStack would be for it to print output that is meaningful to the end user running it. Simply printing a verbose list of every single shell command executed is one of the most unkind things you can do to a user. I’d like to see

 # ./devstack.sh
 * Cloning GIT repositories
     - 1/10 nova
     - 2/10 cinder
     - 3/10 quantum
 * Installing RPMs using YUM
     - 1/30 python-pip
     - 2/30 libvirt
     - 3/30 libvirt-client
 * Installing Python packages to $DEST/vroot/lib/python-2.7/site-packages using PIP
     - 1/24 WebOb
     - 2/24 ampqlib
     - 3/24 boto
 * Creating database schemas
     - 1/10 nova
     - 2/10 cinder
     - 3/10 quantum

By all means still save the full list of every shell command and their output to a ‘devstack.log’ file for troubleshooting when things go wrong.