Introduction to OpenStack
Following links provide you a feeling about the architecture of OpenStack and how the several components interact:
We recommend you to read through the links as well as the OpenStack Starter Guide.
Our Starting Point…
This blog entry describes an openstack multinode installation. As the name implies, this configuration is based on 2 (or more) physical hosts. We use one of the nodes as the so called “cloud controller” and the other one as an additional computing ressource. The hostname of the cloud ontroller is “c2n2”, the hostname of the additional computing ressource node is “c2n1”. Make sure that the domain name resolution works in both directions!
The cloud controller c2n2 will host all basic nova services that are needed for providing a cloud computing environment:
- Glance (manages images for virtual instances)
- Compute (runs virtual instances)
- Network (manages the virtual logical network infrastructure and network traffic within the cloud environment)
- Scheduler (manages the distribution of virtual instances to physical hosts based on metadata they deliver)
- Volume (manages persistant block device storage)
- Rabbit Message Server (provides a communication channel between the several components of OpenStack)
The other physical node provides solely addional computing power. So only the nova-compute (and nova-common) service will be installed on that node. At the end we have one cloud management node (c2n2) which works simultaneously as computing node together with the other node (c2n1).
Our OpenStack test installation is hosted in a vlan seperated lab environment. So our physical nodes are seperated from other physical nodes based on OSI Layer 2 vlans.
Each of our physical nodes is equipped with 2 network interface cards. The following picture shows our topology.
The initial configuration of our 2 physical hosts is as follows:
- operating system: Ubuntu Server 11.10 (Oneiric Ocelot)
- Manual Partitioning:
- 1. Partition: Boot Flag, 50G, ext4, /, (UbuntuServer), sda1
- 2. Partition: 25G, sda2
- 3. Partition: 5G, swap, sda3
Static Network Configuration
root@c2n2:~# cat /etc/network/interfaces # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface eth0 inet static address 10.110.12.2 netmask 255.255.255.0 gateway 10.110.12.254 auto eth1 iface eth1 inet static
root@c2n1:~# cat /etc/network/interfaces # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface eth0 inet static address 10.110.12.1 netmask 255.255.255.0 gateway 10.110.12.254 auto eth1 iface eth1 inet static
The eth1 interfaces on the nodes are left unconfigured – they will be used as bridging devices by openstack.
More on the installation process of openstack after the break…