MultiHost

@kiral
Devstack is meant for development purpose so better would be to check the offical install guide at http://docs.openstack.org It expalins how to setup multinode openstack deployment

I used devstack for successfully install a multi-node (2 nodes) deployment.

Network model FlatDHCP (now struggling with "plain" Flat).

One node plays two roles: controller and compute node.
It runs the following daemons:

- glance-registry
- glance-api
- keystone-all
- mysqld
- rabbitmq (all the daemons)
- nova (all the daemons)

The other node plays compute role running the following daemons:

- nova-api
- nova-network
- nova-compute
- nova-volume

Both the nodes use 3 NICs (they are virtual because the nodes run under VirtualBox, as I said at the very beginning).

- eth0 is used for fixed IP addresses
- eth1 is used for floating IP adresses
- eth2 is used for administration / control purposes (daemons communicate using this eth)

---

Yes, it is possible but you need to:

1) prepare a "localrc" file under directory devstack to override some variable values used during the installation. This is my example:

HOST_IP= 192.168.56.102# change this per compute node
FLAT_INTERFACE=eth0
FIXED_RANGE=10.0.0.0/24
FIXED_NETWORK_SIZE=256
FLOATING_RANGE=10.15.5.225/29
MULTI_HOST=1
LOGFILE=/opt/stack/logs/stack.sh.log
ADMIN_PASSWORD=openstack
MYSQL_PASS=openstack
RABBIT_PASS=openstack
SERVICE_PASSWORD=openstack
SERVICE_TOKEN=openstack
MYSQL_HOST=192.168.56.101
RABBIT_HOST=192.168.56.101
GLANCE_HOSTPORT=192.168.56.101:9292
ENABLED_SERVICES=n-cpu,n-net,n-api,n-vol
MYSQL_PASSWORD=openstack

Please note that ENABLED_SERVICES list the daemons that are actually installed

2) Make some modifications to nova.conf in the compute node (or whatever node that does not play the controller node) in order to make it communicate with the other services running on the controller (DB, RabbitMQ, Glance, Keystone)
The modifications are quite evident.
In order to know all the "properties" you can indicate into nova.conf, try nova-manage config list

3) Depending on the number of NICs you are using and on the purpose of those NICs, you need to modify /etc/network/interfaces.

To me, this is the hardest thing.

On my installation I used three NICs on each node (everything is virtual because I'm using VirtualBox :) ).

This is /etc/network/interfaces for the controller:

# The loopback network interface
auto lo
iface lo inet loopback

# This interface is exclusively used for fixed IP addresses
auto eth0
iface eth0 inet manual
        up ifconfig eth0 up

# This interface is exclusively used for floating IP addresses
auto eth1
iface eth1 inet dhcp

# This interface is used for administration purposes
auto eth2
iface eth2 inet static
        address 192.168.56.101
        netmask 255.255.255.0
        network 192.168.56.0
        broadcast 192.168.56.255

This is /etc/network/interfaces for the compute node:
# The loopback network interface
auto lo
iface lo inet loopback

# This interface is exclusively used for fixed ip addresses
auto eth0
iface eth0 inet manual
        up ifconfig eth0 up

# This interface is exclusively used for floating ip addresses
auto eth1
iface eth1 inet dhcp

# This interface is used for administration purposes
auto eth2
iface eth2 inet static
        address 192.168.56.102
        netmask 255.255.255.0
        network 192.168.56.0
        broadcast 192.168.56.255