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Setting maintenance mode

Set maintenance mode before you conduct diagnostic tests, maintenance, or tuning on a node or server. Maintenance mode can prevent the disruption of client requests by routing client traffic that is targeted for a server or node that is in maintenance mode to another server or node.

Before you begin

  • You can set maintenance mode on a server or a node that is represented in the administrative console.
  • To view the nodes that are configured, click System administration > Middleware nodes. To view all of the servers that are configured, click Servers > All servers.
  • You can use maintenance mode when you route requests with on-demand routers (ODR), servers, or Intelligent Management enabled web servers.
  • ODR maintenance mode is supported when the ODR is fronted by a web server plug-in. The plugin-cfg.xml file generator generates the plug-in to enforce the various modes of node and server maintenance mode. You can use node and server maintenance mode to apply service to the ODR tier in the same way that you use maintenance mode to apply service to the application server tier.
  • Setting a server into maintenance mode is a persistent change. A server remains in maintenance mode until the mode is explicitly changed, even if the server is restarted. The maintenance mode of a server is stored persistently as a server custom property. The name of the custom property is server.maintenancemode.
    The server.maintenancemode property values can be any of the following.
    • false: This value disables the maintenance mode.
    • break: This value stops any traffic from being routed to the server.
    • affinity: This value routes only traffic with affinity to the server.
    • stop: This value stops the server, and persistently sets it in break mode.
Note: Maintenance Mode can only be used when paired with an Intelligent Management enabled front end. For example, the Intelligent Management enabled Plugin or the Java On Demand Router. If either of these front end is not being used, the maintenance mode behaviors cannot be achieved.

About this task

When a node or server is in running state, the dynamic operations environment considers that node or server to be available for servicing application requests. When problems occur, you must conduct diagnostic tests, maintenance, or tuning on a node or server. Use maintenance mode to stop routing traffic to the node or server while you determine the problem.

When a server is in maintenance mode, the application placement controller cannot control that server. The server in maintenance mode does not count toward the dynamic cluster setting for the number of minimum or maximum running instances. For vertical stacking, the configured maximum minus the number of servers in maintenance mode on the node is used to determine whether any servers need to be created on the node. By using this method, the dynamic operations environment does not create or destroy server instances to support the configured maximum number of instances.

You can use maintenance mode to perform node-level maintenance mode for the ODR nodes just as you can perform node-level maintenance mode for application server nodes. Similarly, you can use server maintenance mode for your ODRs just as you can for application servers.

Two routing policies, the permitMM and permitstickyMM routing policies, are work class match actions that you can use to explicitly permit traffic to be routed to application servers in maintenance mode. These policies are not applicable to Session Initiation Protocol (SIP) and Java Message Service traffic types.

Procedure

  1. Place nodes into or out of maintenance mode.
    1. Select the nodes.
      In the administrative console, click System administration > Middleware nodes. Select the nodes for which you want to change the maintenance mode.
    2. Select the maintenance mode.
      Maintenance mode
      Only affinity traffic is allowed to application servers on the node.
      Maintenance immediate stop
      No traffic is directed to the application servers on the node and the application servers on the node are stopped. When the application servers on this node are restarted, no traffic is routed to them until maintenance mode returns to the Normal.
      Normal
      Traffic with and without affinity is permitted to the application servers on the node.
    3. Click Set mode.
  2. Place servers into or out of maintenance mode.
    In the administrative console, click Servers > All servers. Select the servers for which you want to change the maintenance mode.
    1. Select the servers.
    2. Select the maintenance mode.
      Maintenance mode
      Only affinity traffic is allowed to flow to the application server.
      Maintenance mode - break affinity
      No traffic is directed to the application server.
      Maintenance immediate stop
      This mode is the same as the break affinity mode. In this mode, no traffic is directed to the application server and the application server is stopped. When the application server is restarted, it remains in break affinity mode until explicitly set back to normal.
      Normal
      Traffic with and without affinity is permitted to the application server.
    3. Click Set mode.

    After a server is placed into maintenance mode, the changes are synchronized in all nodes. If the cell level custom property maintenanceModeSyncContainingNodeOnly is set to true, the changes are synchronized with the node on which the server resides. This custom property takes effect dynamically without restarting the server.

What to do next

The health controller also uses server maintenance mode as an action that is taken when the health policy is breached. For example, if you are using an excessive response time condition, and the response time exceeds the specified maximum for a server, then the server can move to maintenance mode.