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# Host Resources
 
 
###API Summary 

- [List hosts](hosts.md)
- [View host information](hosts-host.md)
- [Create host](create-host.md)

###Properties

<table>
  <tr>
    <th>Property</th>
    <th>Description</th>
  </tr>
  <tr>
    <td>Hosts/host_name</td>
    <td>The host name</td>  
  </tr>
  <tr>
    <td>Hosts/cluster_name</td>
    <td>The name of the parent cluster</td>  
  </tr>
  <tr>
    <td>Hosts/ip</td>
    <td>The host ip address</td>  
  </tr>
  <tr>
    <td>Hosts/total_mem</td>
    <td>The total memory available on the host</td>  
  </tr>
  <tr>
    <td>Hosts/cpu_count</td>
    <td>The cpu count of the host</td>  
  </tr>
  <tr>
    <td>Hosts/os_arch</td>
    <td>The OS architechture of the host (e.g. x86_64)</td>  
  </tr>
  <tr>
    <td>Hosts/os_type</td>
    <td>The OS type of the host (e.g. centos6)</td>  
  </tr>
  <tr>
    <td>Hosts/rack_info</td>
    <td>The rack info of the host</td>  
  </tr>
  <tr>
    <td>Hosts/last_heartbeat_time</td>
    <td>The time of the last heartbeat from the host in milliseconds since Unix epoch</td>  
  </tr>
  <tr>
    <td>Hosts/last_agent_env</td>
    <td>Environment information from the host</td>  
  </tr>
  <tr>
    <td>Hosts/last_registration_time</td>
    <td>The time of the last registration of the host in milliseconds since Unix epoc</td>  
  </tr>
  <tr>
    <td>Hosts/disk_info</td>
    <td>The host disk information</td>
  </tr>
  <tr>
    <td>Hosts/host_status</td>
    <td>The host status (UNKNOWN, HEALTHY, UNHEALTHY)</td>  
  </tr>
  <tr>
    <td>Hosts/public_host_name</td>
    <td>The public host name.  Note that this property is typically populated during the creation of the host resource in a way that is particular to the environment.  If the public hostname can not be determined then it will be the same as the host_name property. </td>  
  </tr>
  <tr>
    <td>Hosts/host_state</td>
    <td>The host state</td>  
  </tr>
  <tr>
    <td>Hosts/desired_configs</td>
    <td>The desired configurations</td>  
  </tr>
</table>

###States

The current state of a host resource can be determined by looking at the Hosts/host_state property.


    GET api/v1/clusters/c1/hosts/h1?fields=Hosts/host_state

    200 OK
    {
      "href" : "your.ambari.server/api/v1/clusters/c1/hosts/h1?fields=Hosts/host_state",
      "Hosts" : {
        "cluster_name" : "c1",
        "host_state" : "HEALTHY",
        "host_name" : "h1"
      } 
    }

The following table lists the possible values of the host resource Hosts/host_state.
<table>
  <tr>
    <th>State</th>
    <th>Description</th>
  </tr>
  <tr>
    <td>INIT</td>
    <td>New host state.</td>  
  </tr>
  <tr>
    <td>WAITING_FOR_HOST_STATUS_UPDATES</td>
    <td>Registration request is received from the Host but the host has not responded to its status update check.</td>  
  </tr>
  <tr>
    <td>HEALTHY</td>
    <td>The server is receiving heartbeats regularly from the host and the state of the host is healthy.</td>  
  </tr>
  <tr>
    <td>HEARTBEAT_LOST</td>
    <td>The server has not received a heartbeat from the host in the configured heartbeat expiry window.</td>  
  </tr>
  <tr>
    <td>UNHEALTHY</td>
    <td>Host is in unhealthy state as reported either by the Host itself or via any other additional means ( monitoring layer ).</td>  
  </tr>
</table>

