#### 23.4.3.4 Defining Computers in an NDB Cluster

[]()[]()

 The `[computer]` section has no real significance other than serving as a way to avoid the need of defining host names for each node in the system. All parameters mentioned here are required.

* []() `Id`

  []()

  |                                          Version (or later)                                          |   NDB 8.0.13   |
  |------------------------------------------------------------------------------------------------------|----------------|
  |                                            Type or units                                             |     string     |
  |                                               Default                                                |     [...]      |
  |                                                Range                                                 |      ...       |
  |[Restart Type](mysql-cluster-computer-definition.html#mysql-cluster-computer-definition-restart-types)| IS (NDB 8.0.13)|

   This is a unique identifier, used to refer to the host computer elsewhere in the configuration file.

  Important

   The computer ID is *not* the same as the node ID used for a management, API, or data node. Unlike the case with node IDs, you cannot use `NodeId` in place of `Id` in the `[computer]` section of the `config.ini` file.

* []() `HostName`

  []()

  |                                          Version (or later)                                          |    NDB 8.0.13    |
  |------------------------------------------------------------------------------------------------------|------------------|
  |                                            Type or units                                             |name or IP address|
  |                                               Default                                                |      [...]       |
  |                                                Range                                                 |       ...        |
  |[Restart Type](mysql-cluster-computer-definition.html#mysql-cluster-computer-definition-restart-types)|  N (NDB 8.0.13)  |

   This is the computer's hostname or IP address.

[]()**Restart types.**  Information about the restart types used by the parameter descriptions in this section is shown in the following table:

[]()

**Table 23.8 NDB Cluster restart types**

|Symbol|Restart Type|                                                                           Description                                                                           |
|------|------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|
|  N   |    Node    |The parameter can be updated using a rolling restart (see [Section 23.6.5, “Performing a Rolling Restart of an NDB Cluster”](mysql-cluster-rolling-restart.html))|
|  S   |   System   |                              All cluster nodes must be shut down completely, then restarted, to effect a change in this parameter                               |
|  I   |  Initial   |                        Data nodes must be restarted using the [`--initial`](mysql-cluster-programs-ndbd.html#option_ndbd_initial) option                        |

