github.com/chasestarr/deis@v1.13.5-0.20170519182049-1d9e59fbdbfc/docs/installing_deis/system-requirements.rst (about)

     1  :title: System Requirements
     2  :description: System requirements for provisioning Deis.
     3  
     4  .. _system-requirements:
     5  
     6  System Requirements
     7  ===================
     8  
     9  When deploying Deis, it's important to provision machines with adequate resources. Deis is a
    10  highly-available distributed system, which means that Deis components and your deployed applications
    11  will move around the cluster onto healthy hosts as hosts leave the cluster for various reasons
    12  (failures, reboots, autoscalers, etc.). Because of this, you should have ample spare resources on
    13  any machine in your cluster to withstand the additional load of running services for failed machines.
    14  
    15  Resources
    16  ---------
    17  
    18  Deis components consume approximately 2 - 2.5GB of memory across the cluster, and approximately
    19  30GB of hard disk space. Because each machine should be able to absorb additional load should a
    20  machine fail, each machine must have:
    21  
    22  * At least 4GB of RAM (more is better)
    23  * At least 40GB of hard disk space
    24  
    25  Note that these estimates are for Deis and CoreOS only, and there should be ample room for deployed
    26  applications.
    27  
    28  Running smaller machines will likely result in increased system load and has been known to result
    29  in component failures, issues with etcd/fleet, and other problems.
    30  
    31  .. _cluster-size:
    32  
    33  Cluster size
    34  ------------
    35  
    36  For the :ref:`deis-store <Store>` component to work properly, clusters must have at least
    37  three nodes. The ``etcd`` service must always be able to obtain a quorum, and the Ceph
    38  data store must maintain at least three replicas of persistent data.
    39  
    40  See `optimal etcd cluster size`_ and `etcd disaster recovery`_ for further information.
    41  
    42  .. important::
    43  
    44      Deis clusters of less than three nodes are unsupported.
    45  
    46  If running multiple (at least three) machines of an adequate size is unreasonable, it is recommended to
    47  investigate the `Dokku`_ project instead. Dokku is `sponsored`_ by Deis and is ideal for environments
    48  where a highly-available distributed system is not necessary (i.e. local development, testing, etc.).
    49  
    50  Network
    51  -------
    52  
    53  .. include:: ../_includes/_private-network.rst
    54  
    55  .. _`dokku`: https://github.com/progrium/dokku
    56  .. _`optimal etcd cluster size`: https://coreos.com/docs/cluster-management/scaling/etcd-optimal-cluster-size/
    57  .. _`etcd disaster recovery`: https://github.com/coreos/etcd/blob/master/Documentation/admin_guide.md#disaster-recovery
    58  .. _`sponsored`: http://deis.io/deis-sponsors-dokku/