Get Result time for task is taking very long time and timesout

We use Spark on Kubernetes to run batch jobs to analyze flows and produce insights. The flows are read from timeseries database. We have 3 exec instances each having 5g mem + driver (5g mem). We observe the following warning followed by timeout errors after which the job fails. We have been stuck on this for some time and really hoping to get some help from this forum:2021-10-02T16:07:09.459ZGMT WARN dispatcher-CoarseGrainedScheduler TaskSetManager - Stage 52 contains a task of very large size (2842 KiB). The maximum recommended task size is 1000 KiB.

2021-10-02T16:08:19.151ZGMT ERROR task-result-getter-0 RetryingBlockFetcher - Exception while beginning fetch of 1 outstanding blocks
java.io.IOException: Failed to connect to /192.168.7.99:34259
at org.apache.spark.network.client.TransportClientFactory.createClient(TransportClientFactory.java:253)
at org.apache.spark.network.client.TransportClientFactory.createClient(TransportClientFactory.java:195)
at org.apache.spark.network.netty.NettyBlockTransferService$$anon$2.createAndStart(NettyBlockTransferService.scala:122)
at org.apache.spark.network.shuffle.RetryingBlockFetcher.fetchAllOutstanding(RetryingBlockFetcher.java:141)
at org.apache.spark.network.shuffle.RetryingBlockFetcher.start(RetryingBlockFetcher.java:121)
at org.apache.spark.network.netty.NettyBlockTransferService.fetchBlocks(NettyBlockTransferService.scala:143)
at org.apache.spark.network.BlockTransferService.fetchBlockSync(BlockTransferService.scala:103)
at org.apache.spark.storage.BlockManager.fetchRemoteManagedBuffer(BlockManager.scala:1010)
at org.apache.spark.storage.BlockManager.$anonfun$getRemoteBlock$8(BlockManager.scala:954)
at scala.Option.orElse(Option.scala:447)
at org.apache.spark.storage.BlockManager.getRemoteBlock(BlockManager.scala:954)
at org.apache.spark.storage.BlockManager.getRemoteBytes(BlockManager.scala:1092)
at org.apache.spark.scheduler.TaskResultGetter$$anon$3.$anonfun$run$1(TaskResultGetter.scala:88)
at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
at org.apache.spark.util.Utils$.logUncaughtExceptions(Utils.scala:1934)
at org.apache.spark.scheduler.TaskResultGetter$$anon$3.run(TaskResultGetter.scala:63)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection timed out: /192.168.7.99:34259
Caused by: java.net.ConnectException: Connection timed out
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:716)
at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:330)
at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:334)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:702)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:650)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:576)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(Thread.java:748)
2021-10-02T16:08:19.151ZGMT ERROR task-result-getter-2 RetryingBlockFetcher - Exception while beginning fetch of 1 outstanding blocks
java.io.IOException: Failed to connect to /192.168.6.167:42405
at org.apache.spark.network.client.TransportClientFactory.createClient(TransportClientFactory.java:253)
at org.apache.spark.network.client.TransportClientFactory.createClient(TransportClientFactory.java:195)
at org.apache.spark.network.netty.NettyBlockTransferService$$anon$2.createAndStart(NettyBlockTransferService.scala:122)
at org.apache.spark.network.shuffle.RetryingBlockFetcher.fetchAllOutstanding(RetryingBlockFetcher.java:141)
at org.apache.spark.network.shuffle.RetryingBlockFetcher.start(RetryingBlockFetcher.java:121)
at org.apache.spark.network.netty.NettyBlockTransferService.fetchBlocks(NettyBlockTransferService.scala:143)
at org.apache.spark.network.BlockTransferService.fetchBlockSync(BlockTransferService.scala:103)
at org.apache.spark.storage.BlockManager.fetchRemoteManagedBuffer(BlockManager.scala:1010)
at org.apache.spark.storage.BlockManager.$anonfun$getRemoteBlock$8(BlockManager.scala:954)
at scala.Option.orElse(Option.scala:447)
at org.apache.spark.storage.BlockManager.getRemoteBlock(BlockManager.scala:954)
at org.apache.spark.storage.BlockManager.getRemoteBytes(BlockManager.scala:1092)
at org.apache.spark.scheduler.TaskResultGetter$$anon$3.$anonfun$run$1(TaskResultGetter.scala:88)
at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
at org.apache.spark.util.Utils$.logUncaughtExceptions(Utils.scala:1934)
at org.apache.spark.scheduler.TaskResultGetter$$anon$3.run(TaskResultGetter.scala:63)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection timed out: /192.168.6.167:42