Intermittent connectionTimeout errors in spark streaming job - apache-spark

Question

I have a Spark (2.1) streaming job that writes processed data to azure blob storage every batch (with batch interval 1 min). Every now and then (once every couple of hours) I get the 'java.net.ConnectException' with connection timeout message. This does gets retried and eventually succeeds. But this issue is causing delay in the completion of the 1 min streaming batch and is causing it to finish in 2 to 3 min when this error occurs.
Below is the executor log snippet with error message. I have spark.executor.cores=5.
Is there some kind of number of connections limit that might be causing this?
17/10/11 16:09:02 INFO root: {89f867cc-cbd3-4fa9-a549-4e07be3f69b0}: {Starting operation.}
17/10/11 16:09:02 INFO root: {89f867cc-cbd3-4fa9-a549-4e07be3f69b0}: {Starting operation with location 'PRIMARY' per location mode 'PRIMARY_ONLY'.}
17/10/11 16:09:02 INFO root: {89f867cc-cbd3-4fa9-a549-4e07be3f69b0}: {Starting request to 'http://<name>.blob.core.windows.net/rawData/2017/10/11/16/data1.json' at 'Wed, 11 Oct 2017 16:09:02 GMT'.}
17/10/11 16:09:02 INFO root: {89f867cc-cbd3-4fa9-a549-4e07be3f69b0}: {Waiting for response.}
..
17/10/11 16:11:09 WARN root: {89f867cc-cbd3-4fa9-a549-4e07be3f69b0}: {Retryable exception thrown. Class = 'java.net.ConnectException', Message = 'Connection timed out (Connection timed out)'.}
17/10/11 16:11:09 INFO root: {89f867cc-cbd3-4fa9-a549-4e07be3f69b0}: {Checking if the operation should be retried. Retry count = '0', HTTP status code = '-1', Error Message = 'An unknown failure occurred : Connection timed out (Connection timed out)'.}
17/10/11 16:11:09 INFO root: {89f867cc-cbd3-4fa9-a549-4e07be3f69b0}: {The next location has been set to 'PRIMARY', per location mode 'PRIMARY_ONLY'.}
17/10/11 16:11:09 INFO root: {89f867cc-cbd3-4fa9-a549-4e07be3f69b0}: {The retry policy set the next location to 'PRIMARY' and updated the location mode to 'PRIMARY_ONLY'.}
17/10/11 16:11:09 INFO root: {89f867cc-cbd3-4fa9-a549-4e07be3f69b0}: {Operation will be retried after '0'ms.}
17/10/11 16:11:09 INFO root: {89f867cc-cbd3-4fa9-a549-4e07be3f69b0}: {Retrying failed operation.}