Set maintenance mode
Set maintenance mode before performing diagnostic tests, maintenance, or tuning on a node or server. Maintenance mode can prevent the disruption of client requests by routing client traffic targeted for a server or node that is in maintenance mode to another server or node.
- We can set maintenance mode on a server or a node represented in the administrative console.
- To view the nodes configured, click...
System administration > Middleware nodes
To view all of the servers that are configured, click...
Servers > All servers
- Maintenance mode is supported when routing requests with ODRs or proxy servers. Maintenance mode is not recognized when routing requests with a web server..
- 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 appropriately to enforce the various modes of node and server maintenance mode.
Use node and server maintenance mode to apply service to the ODR tier in the same way that we 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 even if the server is restarted, until the mode is explicitly changed. 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:
false Disable the maintenance mode. break Stop any traffic from being routed to the server. affinity Route only traffic with affinity to the server. stop Stop the server, and persistently set server in break mode.
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, we must perform diagnostics, maintenance, or tuning on the node or server. Use maintenance mode to stop routing traffic to the node or server while we determine the problem.
When a server is in maintenance mode, the application placement controller cannot control that server. The server does not count toward the minimum or maximum running instances setting for the dynamic cluster. For vertical stacking, the configured maximum minus the number of servers in maintenance mode on the node is used to determine if 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 as the dynamic cluster instances move in and out of maintenance mode.
We can use maintenance mode to perform node-level maintenance mode for the ODR nodes just as we can perform node-level maintenance mode for application server nodes. Similarly, we can use server maintenance mode for our ODRs just as we can for application servers.
Two routing policies, the permitMM and permitstickyMM routing policies, are work class match actions we can use to route HTTP traffic only to servers in maintenance mode.
Tasks
- Place nodes into or out of maintenance mode.
- Select the nodes. In the administrative console, click...
System administration > Middleware nodes > nodes
- Select the maintenance mode.
- Maintenance mode
- The on demand router continues to send requests with affinity to an application server in this mode, but typically does not send requests without affinity (unless the request matches a rule which explicitly permits it to be routed to an application server in maintenance mode).
- Maintenance immediate stop
- This mode is the same as the break affinity mode, except that the application server is also immediately stopped. When the application server is restarted, it is still in break affinity mode.
- Normal
- The ODR sends requests with and without affinity to an application server in this mode.
- Click Set mode.
- Place servers into or out of maintenance mode. In the administrative console, click...
Servers > All servers > servers
- Select the servers.
- Select the maintenance mode.
- Maintenance mode
- The ODR continues to send requests with affinity to an application server in this mode, but typically does not send requests without affinity (unless the request matches a rule which explicitly permits it to be routed to an application server in maintenance mode).
- Maintenance mode - break affinity
- The ODR typically does not send any requests to an application server in this mode (unless the request matches a rule which explicitly permits it to be routed to an application server in maintenance mode).
- Maintenance immediate stop
- This mode is the same as the break affinity mode, except that the application server is also immediately stopped. When the application server is restarted, it is still in break affinity mode.
- Normal
- The ODR sends requests with and without affinity to an application server in this mode.
- 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. No restart is required.
HTTP and SIP traffic is no longer routed to the nodes or servers that we have in maintenance mode. EJB affinity is not broken. Requests with EJB affinity and JMS traffic are still routed to the server that is in maintenance mode.
What to do next
The health controller also uses server maintenance mode as an action taken when the health policy is breached. For example, if we 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.
Subtopics
Create health policies Create ODRs Routing to servers in maintenance mode Intelligent Management: maintenance mode administrative tasks Intelligent Management: routing and service policies