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Obsolete:NovaInstall/CentOSNotes

Revision as of 02:54, 1 February 2011 by Vladimir (talk)

Nova installation on CentOS 5.5

These are notes for installing OpenStack Compute on CentOS 5.5 and will be updated but are NOT final. Please test for accuracy and edit as you see fit.

The principle bottleneck for running nova on CentOS is Python 2.6. Nova is written in Python 2.6 and CentOS 5.5. comes with python 2.4. We can not update python system wide as some core utilities (like yum) is dependent on python 2.4. Also very few python 2.6 modules are available in centos/epel repos.

Step 1: Get pre-reqs Add euca2ools and EPEL repo first.


cat >/etc/yum.repos.d/euca2ools.repo << EUCA_REPO_CONF_EOF
[eucalyptus]
name=euca2ools
baseurl=http://www.eucalyptussoftware.com/downloads/repo/euca2ools/1.3.1/yum/centos/
enabled=1
gpgcheck=0

EUCA_REPO_CONF_EOF


rpm -Uvh 'http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm'

Step 2: Now install python2.6, kvm and few other libraries through yum


yum -y  install dnsmasq  vblade kpartx kvm gawk iptables ebtables  bzr screen euca2ools  curl rabbitmq-server gcc gcc-c++ autoconf automake swig  openldap openldap-servers python26 python26-devel python26-distribute git openssl-devel  python26-tools mysql-server qemu kmod-kvm libxml2 libxslt libxslt-devel mysql-devel libvirt


Step 3: Then download the latest aoetools and then build (and install) it You also need to check for the latest version on sourceforge because the exact url will change if there's a new release.


    wget -c http://sourceforge.net/projects/aoetools/files/aoetools/32/aoetools-32.tar.gz/download
    tar -zxvf aoetools-32.tar.gz
    cd aoetools-32
    make
    make install


Step 4: Add the udev rules for aoetools


cat > /etc/udev/rules.d/60-aoe.rules << AOE_RULES_EOF
SUBSYSTEM=="aoe", KERNEL=="discover",    NAME="etherd/%k", GROUP="disk", MODE="0220"
SUBSYSTEM=="aoe", KERNEL=="err",    NAME="etherd/%k", GROUP="disk", MODE="0440"
SUBSYSTEM=="aoe", KERNEL=="interfaces",    NAME="etherd/%k", GROUP="disk", MODE="0220"
SUBSYSTEM=="aoe", KERNEL=="revalidate",    NAME="etherd/%k", GROUP="disk", MODE="0220"
# aoe block devices
KERNEL=="etherd*",       NAME="%k", GROUP="disk"
AOE_RULES_EOF

Step 5: Load the kernel modules and python modules


    modprobe aoe
    modprobe kvm
    modprobe nbd


Step 6: Fixing qemu-img

Stock Nova uses a newer version of qemu-img which uses different command line options. To avoid having to rebuild the whole qemu-kvm binary we need to add following wrapper file to qemu-img


mv /usr/bin/qemu-img /usr/bin/qemu-img.bin
cat > /usr/bin/qemu-img <<EOF
#!/bin/sh

ARGS="\$*"

CHANGED_ARGS=`echo \$* | sed "s/-o cluster_size=2M,backing_file=/-b /g"`

/usr/bin/qemu-img.bin  \$CHANGED_ARGS
EOF


Now, install the python modules using easy_install-2.6, this ensures the installation are done against python 2.6


easy_install-2.6 twisted sqlalchemy mox greenlet carrot python-daemon eventlet tornado IPy routes lxml MySQL-python sphinx webob netaddr paste pastedeploy sqlalchemy-migrate glance Cheetah
easy_install-2.6 python-daemon==1.5.5
easy_install-2.6 lockfile==0.8
easy_install-2.6 boto==1.9b
easy_install-2.6 http://python-gflags.googlecode.com/files/python_gflags-1.4-py2.6.egg

Do the same for python2.6-libxml2 module, notice the --with-python and --prefix flags. --with-python ensures we are building it against python2.6 (otherwise it will build against python2.4, which is default).


 wget -c "ftp://xmlsoft.org/libxml2/libxml2-2.7.3.tar.gz"
    tar -zxvf libxml2-2.7.3.tar.gz
    cd libxml2-2.7.3
    ./configure --with-python=/usr/bin/python26 --prefix=/usr
    make all
    make install
    cd python
    python2.6 setup.py install
    cd ..


You will also need M2Crypto. Unfortunately you will need to make a soft link for openssl-devel for it to properly work ie.


ln -s /usr/include/openssl/opensslconf-x86_64.h /usr/include
easy_install-2.6 http://pypi.python.org/packages/source/M/M2Crypto/M2Crypto-0.20.tar.gz#md5=43a4d958a6c892a37ca02


Now you should have a system that is ready to install Nova from a BZR branch (you can use yum to install the bzr package: su -c 'yum install bzr').

Once you are done installing bzr you can use it to check out the latest branch. I qwill check it out to /opt/nova directory e.g.


bzr branch lp:nova /opt/nova

Once you do the cd into /opt/nova directory and type


python26 setup.py install

Once that is done you will need to copy the stock nova-api.conf file from /opt/nova/etc/nova-api.conf to /etc/nova ie.


cp /opt/nova/etc/nova-api.conf /etc/nova


You also need to copy contents of /opt/nova/CA to /var/lib/nova/CA/


rsync -av /opt/nova/CA/ /var/lib/nova/CA/


Create the Database

Make sure you supply flagfile argument as otherwise nova-manage looks in the Nova bin directory for nova.conf


nova-manage --flagfile /etc/nova/nova.conf db sync


Starting services

To start up services I use following script (borrowed from nova.sh)


export PATH=/usr/bin:/bin:/sbin:/usr/sbin

function screen_it {
    screen -S nova -X screen -t $1
    screen -S nova -p $1 -X stuff "$2$NL"
}
   screen -d -m -S nova -t nova
    sleep 1

# Opens up screen with following commands. You will have to go screen by screen
# and press RETURN to start them
screen_it api "/usr/bin/nova-api --nodaemon --flagfile /etc/nova/nova.conf"
screen_it objectstore "/usr/bin/nova-objectstore --nodaemon --flagfile /etc/nova/nova.conf"
screen_it compute "/usr/bin/nova-compute --nodaemon --flagfile /etc/nova/nova.conf"
screen_it network "/usr/bin/nova-network --nodaemon --flagfile /etc/nova/nova.conf"
screen_it scheduler "/usr/bin/nova-scheduler --nodaemon --flagfile /etc/nova/nova.conf"
#screen_it volume "/usr/bin/nova-volume --nodaemon --flagfile /etc/nova/nova.conf"
#screen_it test ". /etc/nova/novarc"
screen -S nova -x


I recommend adding following line to /etc/screenrc


hardstatus alwayslastline "%-Lw%{= BW}%50>%n%f* %t%{-}%+Lw%< %= %H"


It will show the name of all windows at the bottom of the screen