openstack-ansible/doc/source/install-guide/overview-requirements.rst

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Installation requirements

The minimum software requirements for OpenStack-Ansible are well defined, but hardware requirements will vary based on the size of the OpenStack deployment.

CPU requirements

Compute hosts should have multi-core processors that have hardware-assisted virtualization extensions available. These extensions provide a significant performance boost and improve security in virtualized environments.

Infrastructure hosts should have multi-core processors for the best performance. Some services, such as MySQL, greatly benefit from additional CPU cores and other technologies, such as Hyper-threading.

Disk requirements

Different hosts will have different disk space requirements based on the services running on each host:

Deployment hosts

10GB of disk space is sufficient for holding the OpenStack-Ansible repository content and additional required software.

Compute hosts

Disk space requirements will vary depending on the total number of instances running on each host and the amount of disk space allocated to each instance. Compute hosts should have at least 100GB of disk space available at an absolute minimum. Deployers should consider disks that provide higher throughput with lower latency, such as SSD drives in a RAID array.

Storage hosts

Hosts running the Block Storage (cinder) service often consume the most disk space in OpenStack environments. As with compute hosts, deployers should choose disks that provide the highest I/O throughput with the lowest latency for storage hosts. Storage hosts should contain 1TB of disk space at a minimum.

Infrastructure hosts

The OpenStack control plane contains storage-intensive services, such as the Image (glance) service as well as MariaDB. These control plane hosts should have 100GB of disk space available at a minimum.

Logging hosts

An OpenStack-Ansible deployment generates a significant amount of logging. Logs come from a variety of sources, including services running in containers, the containers themselves, and the physical hosts. Logging hosts need additional disk space to hold live and rotated (historical) log files. In addition, the storage performance must be enough to keep pace with the log traffic coming from various hosts and containers within the OpenStack environment. Deployers should reserve at least 50GB of disk space for storing logs on the logging hosts, but this minimum will grow as additional hosts are deployed.

Hosts that provide Block Storage (cinder) volumes should have logical volume manager (LVM) support. Those hosts must have a cinder-volumes volume group that OpenStack-Ansible can configure for use with cinder.

Each control plane host will run services inside LXC containers. By default, the container filesystems are deployed onto the root filesystem of each control plane hosts. Deployers have the option to deploy those container filesystems into logical volumes by creating a volume group called lxc. OpenStack-Ansible will create a 5GB logical volume for the filesystem of each container running on the host.

Network requirements

It is possible to deploy an OpenStack environment with only one physical network interface. This works for small environments but it will cause problems when the environment grows.

For the best performance, reliability and scalability, deployers should consider a network configuration that contains the following features:

• Bonded network interfaces: Increases performance and/or reliability (dependent on bonding architecture)
• VLAN offloading: Increases performance by adding and removing VLAN tags in hardware, rather than in the server's main CPU
• Gigabit or 10 Gigabit Ethernet: Supports higher network speeds, which can also improve storage performance when using the Block Storage (cinder) service
• Jumbo frames: Increases network performance by allowing more data to be sent in each packet

Software requirements

All hosts within an OpenStack-Ansible environment must meet the following minimum requirements:

• Ubuntu 14.04 LTS (Trusty Tahr)
  • OSA is tested regularly against the latest Ubuntu 14.04 LTS point releases
  • Linux kernel version 3.13.0-34-generic or later
  • For swift storage hosts, you must enable the trusty-backports repositories in /etc/apt/sources.list or /etc/apt/sources.list.d/ See the Ubuntu documentation for more detailed instructions.
• Secure Shell (SSH) client and server that supports public key authentication
• Network Time Protocol (NTP) client for time synchronization (such as ntpd or chronyd)
• Python 2.7 or later

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