github.com/dahs81/otto@v0.2.1-0.20160126165905-6400716cf085/website/source/docs/concepts/ha.html.markdown (about)

     1  ---
     2  layout: "docs"
     3  page_title: "High Availability"
     4  sidebar_current: "docs-concepts-ha"
     5  description: |-
     6    Vault can be highly available, allowing you to run multiple Vaults to protect against outages.
     7  ---
     8  
     9  # High Availability Mode (HA)
    10  
    11  Vault supports multi-server mode for high availability. This mode protects
    12  against outages by running multiple Vault servers. High availability mode
    13  is automatically enabled when using a storage backend that supports it.
    14  
    15  You can tell if a backend supports high availability mode ("HA") by
    16  starting the server and seeing if "(HA available)" is outputted next to
    17  the backend information. If it is, then HA will begin happening automatically.
    18  
    19  To be highly available, Vault elects a leader and does request forwarding to
    20  the leader. Due to this architecture, HA does not enable increased scalability.
    21  In general, the bottleneck of Vault is the storage backend itself, not
    22  Vault core. For example: to increase scalability of Vault with Consul, you
    23  would scale Consul instead of Vault.
    24  
    25  In addition to using a backend that supports HA, you have to configure
    26  Vault with an _advertise address_. This is the address that Vault advertises
    27  to other Vault servers in the cluster for request forwarding. By default,
    28  Vault will use the first private IP address it finds, but you can override
    29  this to any address you want.
    30  
    31  ## Backend Support
    32  
    33  Currently there are several backends that support high availability mode,
    34  including Consul, ZooKeeper and etcd. These may change over time, and the
    35  [configuration page](/docs/config/index.html) should be referenced.
    36  
    37  The Consul backend is the recommended HA backend, as it is used in production
    38  by HashiCorp and it's customers with commercial support.
    39  
    40  If you're interested in implementing another backend or adding HA support
    41  to another backend, we'd love your contributions. Adding HA support
    42  requires implementing the `physical.HABackend` interface for the storage backend.