You can add, edit, and remove child servers by using the EngineManagement
action. This action updates the DIH configuration file, so that the changes are persistent.
For more details about the EngineManagement
action, refer to the DIH Reference.
You can add a new child server to the DIH by using the EngineManagement
action.
NOTE: You can add a child server only in certain distribution modes.
To add a child server
Send the EngineManagement
action, with EngineAction
set to Add
. Set Host
and Port
to the host name and port of the child server.
You can optionally also set other parameters for the child server, such as Disabled
, Weight
, UpdateOnly
, and Polling
. For the full list of available parameters, see the DIH Reference.
TIP: By default, when you add a child server in this way, the DIH pings the specified host and port. The Add
action fails if the child server is not running. Set Disabled
to True
to skip this step and add the child server in the offline state.
In consistent hashing mode, you can remove a child server or group. For more information about this mode, see Use Consistent Hashing.
To remove a child server in this mode, you must first set Weight
to 0
(zero), and then use the DREREDISTRIBUTE
index action to redistribute the virtual nodes. For more information, see Remove a Child Server.
You can use the EngineManagement
action to dynamically change the settings for a child server.
To update a child server
Send the EngineManagement
action, with EngineAction
set to Edit
. Set the ID
parameter to the ID of the child server that you want to modify.
Set any of the optional parameters that you want to change for the child server, such as Disabled
, Weight
, UpdateOnly
, and Polling
.
You can also update the host and port of the server, for example replace a server that has become permanently inaccessible. In consistent hashing mode, you can use stored replicas to rebuild the lost server. For more information, see Restore Child Servers in Consistent Hashing Mode.