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Hardware considerations for high availability
When you use high availability, consider the hardware requirements needed for your application.
Hardware setup
The following are the standard hardware requirements:
- Provider networks: See the Overview -> Networking Option 1: Provider networks section of the Install Guides depending on your distribution.
- Self-service networks: See the Overview -> Networking Option 2: Self-service networks section of the Install Guides depending on your distribution.
OpenStack does not require a significant amount of resources and the following minimum requirements should support a proof-of-concept high availability environment with core services and several instances:
| Node type | Processor Cores | Memory | Storage | NIC |
|---|---|---|---|---|
| controller node | 4 | 12 GB | 120 GB | 2 |
| compute node | 8+ | 12+ GB | 120+ GB | 2 |
We recommended that the maximum latency between any two controller nodes is 2 milliseconds. Although the cluster software can be tuned to operate at higher latencies, some vendors insist on this value before agreeing to support the installation.
You can use the ping command to find the latency between two servers.
Virtualized hardware
For demonstrations and studying, you can set up a test environment on virtual machines (VMs). This has the following benefits:
- One physical server can support multiple nodes, each of which supports almost any number of network interfaces.
- You can take periodic snap shots throughout the installation process and roll back to a working configuration in the event of a problem.
However, running an OpenStack environment on VMs degrades the performance of your instances, particularly if your hypervisor or processor lacks support for hardware acceleration of nested VMs.
Note
When installing highly available OpenStack on VMs, be sure that your hypervisor permits promiscuous mode and disables MAC address filtering on the external network.