Column Display Related Tasks Related Topics
This page allows you to customize the column display in the table, create a new migratable target, and delete a migratable target. A migratable target is a target that is active on at-most one server of a cluster at a time and which controls the servers that can host a pinned migratable service. Migratable services include JMS servers, SAF agents, path service, and custom persistent stores. You can manually migrate a migratable target or you configure it for automatic migration.
You can show fewer or additional data points on this page by expanding Customize this table and modifying the Column Display list. Each data point displays in its own table column.
The following table lists all of the data points that you can display in columns on this page.
Name Description Name
The name that you specified when you created the migratable target.
Returns the cluster this singleton service is associated with.
User Preferred Server
Returns the server that the user prefers the singleton service to be active on.
The list of servers that are candidates to host the migratable services deployed to this migratable target. If the constrainedCandidateServers list is empty, all servers in the cluster are returned. If the constrainedCandidateServers list is not empty, only those servers will be returned. The user-preferred server will be the first element in the list.
Defines the type of migration policy to use for the services hosted by this migratable target. Valid options are:
Manual Service Migration Only
Indicates that no automatic migration of services hosted by this migratable target will occur.
Auto-Migrate Exactly-Once Services
Indicates that if at least one Managed Server in the candidate server list is running, the services hosted by this migratable target will be active somewhere in the cluster if servers should fail or are administratively shut down (either gracefully or forcibly). For example, it is a recommended best practice to use this policy when a migratable target hosts a path service, so if its preferred server fails or is shut down, the path service will automatically migrate to another candidate server, and so will always be active in the cluster.
Note This value can lead to target grouping on a server member. For example, if you have five exactly-once migratable targets and only one Managed Server is started in the cluster, then all five targets will be activated on that server.
Auto-Migrate Failure-Recovery Services
Indicates that the services hosted by this migratable target will only start if the migratable target's User Preferred Server (UPS) is started. If an administrator manually shuts down the UPS, either gracefully or forcibly, then a failure-recovery service will not migrate. However, if the UPS fails due to an internal error, then the service will be migrated to another candidate server. If such a candidate server is unavailable (due to either a manual shutdown or an internal failure), then the migration framework will first attempt to reactivate the service on its UPS server. If the UPS server is not available at that time, then the service will be migrated to another candidate server.
Auto-Migrate Shutdown-Recovery Services
Indicates that the services hosted by this migratable target will migrate to one of the candidate servers, if server is administratively shut down (either gracefully or forcibly). Once recovery is done, service is migrated back to failed server.
Pre-Migration Script Path
Specifies the path to the pre-migration script to run before a migratable target is actually activated. The script must be in the
Before the migratable target is activated, if there is a script specified, and Node Manager is available, then the script will run. Specifying a script without an available Node Manager will result in an error upon migration.
If the script fails or cannot be found, migration will not proceed on the current server, and will be tried on the next suitable server. This could be the next server in the candidate server list, or in the cluster, if there is no candidate server list.
Post-Migration Script Path
Specifies the path to the post-migration script to run after a migratable target is fully deactivated. The script must be in the
After the migratable target is deactivated, if there is a script specified, and Node Manager is available, then the script will run. Specifying a script without an available Node Manager will result in an error upon migration.
Post-Migration Script Failure Fatal
Specifies whether or not a failure during execution of the post-deactivation script is fatal to the migration.
If it is fatal, the migratable target will not be automatically migrated until an administrator manually migrates it to a server, thus reactivating it.
Note: Enabling this value will result in weakening the exactly-once guarantee. It is provided to prevent more dangerous data corruption if the post-deactivation script fails. Also if this value is enabled, then the script may be called more than once by the migration framework after the Migratable Target is deactivated or the server or machine hosting the Migratable Target crashed or is network partitioned. The script is expected not to return different exit values when invoked multiple times in such scenarios.
Non-local Post-Migration Script Allowed
Specifies whether or not the post-deactivation script is allowed to run on a different machine.
Normally, when auto migration occurs, the post-deactivation script will be run on the service's current location, and the pre-activation script on the service's new location. If the current location is unreachable for some reason, this value will be checked to see if it is safe to run it on the service's new machine.
This is useful if the post-deactivation script controls access to a networked resource and does not need any data from the current machine.
Restart On Failure
Specifies whether or not a failed service will first be deactivated and reactivated in place, instead of being migrated.
The number of restart attempts is controlled by NumberOfRestartAttempts . Once these restart attempts are exhausted, the service will migrate. A restarting migratable target will deactivate all services on it in order, then reactivate them all.
Seconds Between Restarts
Specifies how many seconds to wait in between attempts to restart the failed service.
Number Of Restart Attempts
Specifies how many restart attempts to make before migrating the failed service.
Note that these are consecutive attempts. If the value is set to 6, and the service restart fails 5 times before succeeding, but then fails again later, it will not instantly migrate. Each failure gets its own count of restart attempts.
A value of 0 is identical to setting RestartOnFailure to false. A value of -1 indicates the service shouldnever be migrated; instead, it will be restarted until it either works or the server shuts down.
- Configure server migration in a cluster
- Configure JMS Services for migration and high availability
- Configure the JTA Transaction Recovery Service for migration