Getting started with OpenStack Nova

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Revision as of 06:53, 9 September 2011 by Markmc (Talk | contribs)

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Contents

Initial Installation

To get started with OpenStack's Compute Service (Nova), you can install it on Fedora 16:

$> sudo yum install --enablerepo=updates-testing openstack-nova

Nova requires the RabbitMQ AMQP messaging server to be running:

$> sudo service rabbitmq-server start
$> sudo chkconfig rabbitmq-server on

Nova requires the libvirtd server to be running:

$> sudo service libvirtd start
$> sudo chkconfig libvirtd on

Unfortunately, SELinux currently needs to be disabled:

$> sudo setenforce 0

Next, you should enable the Glance API and registry services:

$> for svc in api registry; do sudo service openstack-glance-$svc start; done
$> for svc in api registry; do sudo chkconfig openstack-glance-$svc on; done

The openstack-nova-volume service requires an LVM Volume Group called nova-volumes to exist. We simply create this using a loopback sparse disk image.

$> sudo dd if=/dev/zero of=/var/lib/nova/nova-volumes.img bs=1M seek=10k count=0
$> sudo vgcreate nova-volumes $(sudo losetup --show -f /var/lib/nova/nova-volumes.img)

Now you can start the various services:

$> for svc in api objectstore compute network volume scheduler; do sudo service openstack-nova-$svc start; done
$> for svc in api objectstore compute network volume scheduler; do sudo chkconfig openstack-nova-$svc on; done

Check that all the services started up correctly and look in the logs in /var/log/nova for errors. If there are none, then Nova is up and running!

Admin User, Project and Network Setup

Now you should create an admin user, project and network. I'm going to name them all after myself:

$> sudo nova-manage user admin markmc
$> sudo nova-manage project create markmc markmc
$> sudo nova-manage network create markmc 10.0.0.0/24 1 256 --bridge=br0

Then download a set of credentials for this user/project:

$> sudo nova-manage project zipfile markmc markmc
$> sudo chmod 600 nova.zip
$> sudo chown markmc:markmc nova.zip

Unpack the credentials, source the novarc and add an SSH keypair:

$> mkdir novacreds && cd novacreds
$> unzip ../nova.zip
$> . ./novarc
$> ssh-keygen -f nova_key
$> euca-add-keypair nova_key > nova_key.priv
$> chmod 600 nova*

Images

To run an instance, you're going to need an image. Two options are described below:

  1. Building a Fedora 15 image using Oz
  2. Downloading Ubuntu based minimal images used by OpenStack developers for testing

Building an Image With Oz

You can very easily build an image using Oz. First, make sure it's installed:

$> sudo yum install /usr/bin/oz-install

Create a template definition file called f15.tdl containing:

<template>
 <name>fedora15_x86_64</name>
 <description>My Fedora 15 x86_64 template</description>
 <os>
  <name>Fedora</name>
  <version>15</version>
  <arch>x86_64</arch>
  <install type='url'>
    <url>http://download.fedoraproject.org/pub/fedora/linux/releases/15/Fedora/x86_64/os/</url>
  </install>
 </os>
 <commands>
   <command name='setup-rc-local'>
sed -i 's/rhgb quiet/console=ttyS0/' /boot/grub/grub.conf
 
cat >> /etc/rc.local &lt;&lt; EOF
if [ ! -d /root/.ssh ]; then
  mkdir -p /root/.ssh
  chmod 700 /root/.ssh
fi
 
# Fetch public key using HTTP
ATTEMPTS=10
while [ ! -f /root/.ssh/authorized_keys ]; do
    curl -f http://169.254.169.254/latest/meta-data/public-keys/0/openssh-key > /tmp/aws-key 2>/dev/null
    if [ \$? -eq 0 ]; then
        cat /tmp/aws-key >> /root/.ssh/authorized_keys
        chmod 0600 /root/.ssh/authorized_keys
        restorecon /root/.ssh/authorized_keys
        rm -f /tmp/aws-key
        echo "Successfully retrieved AWS public key from instance metadata"
    else
        FAILED=\$((\$FAILED + 1))
        if [ \$FAILED -ge \$ATTEMPTS ]; then
            echo "Failed to retrieve AWS public key after \$FAILED attempts, quitting"
            break
        fi
        echo "Could not retrieve AWS public key (attempt #\$FAILED/\$ATTEMPTS), retrying in 5 seconds..."
        sleep 5
    fi
done
EOF
   </command>
 </commands>
</template>
 

Then simply do:

$> sudo oz-install -d4 -u f15.tdl

One built, you simply have to register the image with Nova:

$> sudo nova-manage image image_register /var/lib/libvirt/images/fedora15_x86_64.dsk markmc f15
$> glance index

The last command should return a list of the images registered with the Glance image registry.

Downloading Existing Images

If you don't want to build an image, just download this set of images commonly used by OpenStack developers for testing and register them with Nova:

$> mkdir images
$> curl http://images.ansolabs.com/tty.tgz | tar xvfzo -
$> cd ..
$> sudo nova-manage image convert images/

Launch an Instance

As a last step before launching, make sure the nbd kernel module is loaded so that injecting SSH key files into the filesystem on the qcow2 image works:

$> sudo modprobe nbd

You should now be able to launch an image:

$> euca-run-instances f15 -k nova_key

Or, in the case of the downloaded images:

$> euca-run-instances ami-tty --kernel aki-tty --ramdisk ari-tty -k nova_key

And then observe the instance running, observe the KVM VM running and SSH into the instance:

$> euca-describe-instances
$> sudo virsh list
$> ssh -i nova_key.priv root@10.0.0.2
$> euca-get-console-output i-00000001
$> euca-terminate-instances i-00000001