| title: | System Requirements |
|---|---|
| description: | System requirements for provisioning Deis. |
When deploying Deis, it's important to provision machines with adequate resources. Deis is a highly-available distributed system, which means that Deis components and your deployed applications will move around the cluster onto healthy hosts as hosts leave the cluster for various reasons (failures, reboots, autoscalers, etc.). Because of this, you should have ample spare resources on any machine in your cluster to withstand the additional load of running services for failed machines.
Deis components consume approximately 2 - 2.5GB of memory across the cluster, and approximately 30GB of hard disk space. Because each machine should be able to absorb additional load should a machine fail, each machine must have:
- At least 4GB of RAM (more is better)
- At least 40GB of hard disk space
Note that these estimates are for Deis and CoreOS only, and there should be ample room for deployed applications.
Running smaller machines will likely result in increased system load and has been known to result in component failures, issues with etcd/fleet, and other problems.
For scheduling to work properly, clusters must consist of at least three nodes and always have an odd number of members. This is mostly because the underlying CoreOS cluster must always be able to obtain a quorum (see optimal etcd cluster size). Additionally, the :ref:`Store` component keeps three replicas of stored data, so it requires at least three nodes.
Important
Deis clusters of less than three nodes are unsupported.
If running multiple (at least three) machines of an adequate size is unreasonable, it is recommended to investigate the Dokku project instead. Dokku is sponsored by Deis and is ideal for environments where a highly-available distributed system is not necessary (i.e. local development, testing, etc.).