Installing Additional Compute NodesThere are many different ways to perform a multi-node
install of Compute in order to scale out your deployment and
run more compute nodes, enabling more virtual machines to run
simultaneously.If your goal is to split your VM load across more than one
server, you can connect an additional nova-compute node to a cloud
controller node. This configuring can be reproduced on
multiple compute servers to start building a true multi-node
OpenStack Compute cluster.To build out and scale the Compute platform, you spread out
services amongst many servers. While there are additional ways
to accomplish the build-out, this section describes adding
compute nodes, and the service we are scaling out is called
nova-compute.Ensure that the networking on each compute node is configured as documented in the Pre-configuring the network
section.In this case, you can install all the nova- packages and
dependencies as you did for the Cloud Controller node, or just
install nova-compute. Your installation can run any nova-
services anywhere, so long as the service can access
nova.conf so it knows where the
RabbitMQ or Qpid messaging server is installed.When running in a high-availability mode for networking, the
compute node is where you configure the compute network, the
networking between your instances. Learn more about
high-availability for networking in the Compute Administration
manual.Because you may need to query the database from the compute
node and learn more information about instances, the nova
client and MySQL client or PostgresSQL client packages should
be installed on any additional compute nodes.Copy the nova.conf from your controller node to all additional
compute nodes. Modify the following configuration options so that they match the IP address of the compute
host:my_ipvncserver_listenvncserver_proxyclient_addressBy default, Nova sets the bridge device based on the
setting in flat_network_bridge. Now
you can edit
/etc/network/interfaces with
the following template, updated with your IP
information.# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto br100
iface br100 inet static
bridge_ports eth0
bridge_stp off
bridge_maxwait 0
bridge_fd 0
address xxx.xxx.xxx.xxx
netmask xxx.xxx.xxx.xxx
network xxx.xxx.xxx.xxx
broadcast xxx.xxx.xxx.xxx
gateway xxx.xxx.xxx.xxx
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers xxx.xxx.xxx.xxxRestart networking:$sudo service networking restartWith nova.conf updated and
networking set, configuration is nearly complete.
First, bounce the relevant services to take the latest
updates:$sudo service libvirtd restart
$ sudo service nova-compute restartTo avoid issues with KVM and permissions with Nova,
run the following commands to ensure we have VM's that
are running optimally:#chgrp kvm /dev/kvm#chmod g+rwx /dev/kvmIf you want to use the 10.04 Ubuntu Enterprise Cloud
images that are readily available at
http://uec-images.ubuntu.com/releases/10.04/release/,
you may run into delays with booting. Any server that
does not have nova-api running on
it needs this iptables entry so that UEC images can
get metadata info. On compute nodes, configure the
iptables with this next step:#iptables -t nat -A PREROUTING -d 169.254.169.254/32 -p tcp -m tcp --dport 80 -j DNAT --to-destination $NOVA_API_IP:8773Lastly, confirm that your compute node is talking to
your cloud controller. From the cloud controller, run
this database query:$mysql -u$MYSQL_USER -p$MYSQL_PASS nova -e 'select * from services;'In return, you should see something similar to
this:+---------------------+---------------------+------------+---------+----+----------+----------------+-----------+--------------+----------+-------------------+
| created_at | updated_at | deleted_at | deleted | id | host | binary | topic | report_count | disabled | availability_zone |
+---------------------+---------------------+------------+---------+----+----------+----------------+-----------+--------------+----------+-------------------+
| 2011-01-28 22:52:46 | 2011-02-03 06:55:48 | NULL | 0 | 1 | osdemo02 | nova-network | network | 46064 | 0 | nova |
| 2011-01-28 22:52:48 | 2011-02-03 06:55:57 | NULL | 0 | 2 | osdemo02 | nova-compute | compute | 46056 | 0 | nova |
| 2011-01-28 22:52:52 | 2011-02-03 06:55:50 | NULL | 0 | 3 | osdemo02 | nova-scheduler | scheduler | 46065 | 0 | nova |
| 2011-01-29 23:49:29 | 2011-02-03 06:54:26 | NULL | 0 | 4 | osdemo01 | nova-compute | compute | 37050 | 0 | nova |
| 2011-01-30 23:42:24 | 2011-02-03 06:55:44 | NULL | 0 | 9 | osdemo04 | nova-compute | compute | 28484 | 0 | nova |
| 2011-01-30 21:27:28 | 2011-02-03 06:54:23 | NULL | 0 | 8 | osdemo05 | nova-compute | compute | 29284 | 0 | nova |
+---------------------+---------------------+------------+---------+----+----------+----------------+-----------+--------------+----------+-------------------+You can see that osdemo0{1,2,4,5}
are all running nova-compute. When you start
spinning up instances, they will allocate on any node
that is running nova-compute from this list.