== [[LauncherBackend]] LauncherBackend

LauncherBackend is the <> of <> that can <>.

[[contract]] .LauncherBackend Contract (Abstract Methods Only) [cols="1m,3",options="header",width="100%"] |=== | Method | Description

| conf a| [[conf]]

[source, scala]¶

conf: SparkConf¶

SparkConf.md[]

Used exclusively when LauncherBackend is requested to <> (to access configuration-properties.md#spark.launcher.port[spark.launcher.port] and configuration-properties.md#spark.launcher.secret[spark.launcher.secret] configuration properties)

| onStopRequest a| [[onStopRequest]]

[source, scala]¶

onStopRequest(): Unit¶

Handles stop requests (to stop the Spark application as gracefully as possible)

Used exclusively when LauncherBackend is requested to <>

|===

[[creating-instance]] LauncherBackend takes no arguments to be created.

NOTE: LauncherBackend is a Scala abstract class and cannot be <> directly. It is created indirectly for the <>.

[[internal-registries]] .LauncherBackend's Internal Properties (e.g. Registries, Counters and Flags) [cols="1m,3",options="header",width="100%"] |=== | Name | Description

| _isConnected a| [[_isConnected]][[isConnected]] Flag that says whether...FIXME (true) or not (false)

Default: false

Used when...FIXME

| clientThread a| [[clientThread]] Java's https://docs.oracle.com/javase/8/docs/api/java/lang/Thread.html[java.lang.Thread]

Used when...FIXME

| connection a| [[connection]] BackendConnection

Used when...FIXME

| lastState a| [[lastState]] SparkAppHandle.State

Used when...FIXME

|===

[[implementations]] LauncherBackend is <> (as an anonymous class) for the following:

• Spark on YARN's <>

• Spark local's <>

• Spark on Mesos' <>

• Spark Standalone's <>

=== [[close]] Closing -- close Method

[source, scala]¶

close(): Unit¶

close...FIXME

NOTE: close is used when...FIXME

=== [[connect]] Connecting -- connect Method

[source, scala]¶

connect(): Unit¶

connect...FIXME

[NOTE]¶

connect is used when:

• Spark Standalone's StandaloneSchedulerBackend is requested to <> (in client deploy mode)

• Spark local's LocalSchedulerBackend is <>

• Spark on Mesos' MesosCoarseGrainedSchedulerBackend is requested to <> (in client deploy mode)

* Spark on YARN's Client is requested to <>¶

=== [[fireStopRequest]] fireStopRequest Internal Method

[source, scala]¶

fireStopRequest(): Unit¶

fireStopRequest...FIXME

NOTE: fireStopRequest is used exclusively when BackendConnection is requested to handle a Stop message.

=== [[onDisconnected]] Handling Disconnects From Scheduling Backend -- onDisconnected Method

[source, scala]¶

onDisconnected(): Unit¶

onDisconnected does nothing by default and is expected to be overriden by <>.

NOTE: onDisconnected is used when...FIXME

=== [[setAppId]] setAppId Method

[source, scala]¶

setAppId(appId: String): Unit¶

setAppId...FIXME

NOTE: setAppId is used when...FIXME

=== [[setState]] setState Method

[source, scala]¶

setState(state: SparkAppHandle.State): Unit¶

setState...FIXME

NOTE: setState is used when...FIXME