Maintenance mode

The maintenance mode feature allows a host or server to be taken offline without disrupting service. Maintenance mode works with the dynamic routing and auto scaling features to prevent the disruption of client requests by routing client traffic around a server that is in maintenance mode, to another server. Enter maintenance mode before you perform diagnostic tests, maintenance, or tuning, on a host or server.

Server maintenance mode

  • A server in maintenance mode is not included in the count of active servers in an auto scaled cluster.
  • When a server is in maintenance mode the dynamic routing feature routes requests to other servers in the collective.

Host maintenance mode

  • All servers on the host are entered in to maintenance mode when the host is placed in maintenance mode.
  • All servers move out of maintenance mode when a host is taken out of maintenance mode.
  • A host in maintenance mode makes that host unavailable for provisioning a new Liberty instance.
  • Any server on a host in maintenance mode may be individually taken out of maintenance mode while a host remains in maintenance mode.

Maintenance mode collective command options

Maintenance mode is controlled by an administrator by using the collective command. This command is expanded to include syntax for entering or exiting maintenance mode.

Command Syntax
  • collective enterMaintenanceMode [options]
  • collective exitMaintenanceMode [options]
  • collective getMaintenanceMode [options]

Base collective command options

--host="controller host name"
Required - Name of the host on which the collective controller resides.
--port="controller HTTPS port"
Required - Specifies the HTTPS port number of the target collective controller.
--user="user"
Required - The administrative user of the target collective controller.
--password="password"
Required - The administrative user's password.

Maintenance mode specific options

--hostName="target Host Name"
Required - The name of the host going into maintenance mode or the host that contains the server going into maintenance mode.
--usrDir="Liberty installation directory"
Required for Server - The root directory where Liberty is installed on the host.
--server="server Name"
Required for Server - The name of the server being placed into maintenance mode
--break
Applies to enterMaintenanceMode only.

When not specified the default is to stop new traffic to the server, but allow traffic with affinity to continue to use the server that has entered maintenance mode. When --break is specified all requests are routed to another server.

--force
Applies to enterMaintenanceMode only.

When --force is specified, the server will be forced to enter maintenance mode even if an auto scaling policy will be violated.


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