[SPARK-7995][SPARK-6280][CORE] Remove AkkaRpcEnv and remove systemName from setupEndpointRef

### Remove AkkaRpcEnv

Keep `SparkEnv.actorSystem` because Streaming still uses it. Will remove it and AkkaUtils after refactoring Streaming actorStream API.

### Remove systemName
There are 2 places using `systemName`:
* `RpcEnvConfig.name`. Actually, although it's used as `systemName` in `AkkaRpcEnv`, `NettyRpcEnv` uses it as the service name to output the log `Successfully started service *** on port ***`. Since the service name in log is useful, I keep `RpcEnvConfig.name`.
* `def setupEndpointRef(systemName: String, address: RpcAddress, endpointName: String)`. Each `ActorSystem` has a `systemName`. Akka requires `systemName` in its URI and will refuse a connection if `systemName` is not matched. However, `NettyRpcEnv` doesn't use it. So we can remove `systemName` from `setupEndpointRef` since we are removing `AkkaRpcEnv`.

### Remove RpcEnv.uriOf

`uriOf` exists because Akka uses different URI formats for with and without authentication, e.g., `akka.ssl.tcp...` and `akka.tcp://...`. But `NettyRpcEnv` uses the same format. So it's not necessary after removing `AkkaRpcEnv`.

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #10459 from zsxwing/remove-akka-rpc-env.

1 files changed, 2 insertions, 1 deletions

diff --git a/core/src/main/scala/org/apache/spark/SparkConf.scala b/core/src/main/scala/org/apache/spark/SparkConf.scala
index d3384fb297..ff2c4c34c0 100644
--- a/core/src/main/scala/org/apache/spark/SparkConf.scala
+++ b/core/src/main/scala/org/apache/spark/SparkConf.scala
@@ -544,7 +544,8 @@ private[spark] object SparkConf extends Logging {
       DeprecatedConfig("spark.kryoserializer.buffer.mb", "1.4",
         "Please use spark.kryoserializer.buffer instead. The default value for " +
           "spark.kryoserializer.buffer.mb was previously specified as '0.064'. Fractional values " +
-          "are no longer accepted. To specify the equivalent now, one may use '64k'.")
+          "are no longer accepted. To specify the equivalent now, one may use '64k'."),
+      DeprecatedConfig("spark.rpc", "2.0", "Not used any more.")
     )
 
     Map(configs.map { cfg => (cfg.key -> cfg) } : _*)