This is a follow up for this unanswered October 2015 issue: http://apache-spark-developers-list.1001551.n3.nabble.com/Spark-streaming-failed-recovery-from-checkpoint-td14832.html
The issue is that the Spark driver checkpoints an RDD, deletes it, the job restarts, and *the new driver tries to load the deleted checkpoint RDD*. The application is run in YARN, which attempts to restart the application a number of times (100 in our case), all of which fail due to missing the deleted RDD. Here is a Splunk log which shows the inconsistency in checkpoint behaviour: *2016-10-09 02:48:43,533* [streaming-job-executor-0] INFO org.apache.spark.rdd.ReliableRDDCheckpointData - Done checkpointing RDD 73847 to hdfs://proc-job/checkpoint/cadf8dcf-ebc2-4366-a2e1-0939976c6ce1/*rdd-73847*, new parent is RDD 73872 host = ip-10-1-1-13.ec2.internal *2016-10-09 02:53:14,696* [JobGenerator] INFO org.apache.spark.streaming.dstream.DStreamCheckpointData - Deleted checkpoint file 'hdfs://proc-job/checkpoint/cadf8dcf-ebc2-4366-a2e1-0939976c6ce1/*rdd-73847*' for time 1475981310000 ms host = ip-10-1-1-13.ec2.internal *Job restarts here, notice driver host change from ip-10-1-1-13.ec2.internal to ip-10-1-1-25.ec2.internal.* *2016-10-09 02:53:30,175* [Driver] INFO org.apache.spark.streaming.dstream.DStreamCheckpointData - Restoring checkpointed RDD for time 1475981310000 ms from file 'hdfs://proc-job/checkpoint/cadf8dcf-ebc2-4366-a2e1-0939976c6ce1/*rdd-73847*' host = ip-10-1-1-25.ec2.internal *2016-10-09 02:53:30,491* [Driver] ERROR org.apache.spark.deploy.yarn.ApplicationMaster - User class threw exception: java.lang.IllegalArgumentException: requirement failed: Checkpoint directory does not exist: hdfs://proc-job/checkpoint/cadf8dcf-ebc2-4366-a2e1-0939976c6ce1/*rdd-73847* java.lang.IllegalArgumentException: requirement failed: Checkpoint directory does not exist: hdfs://proc-job/checkpoint/cadf8dcf-ebc2-4366-a2e1-0939976c6ce1/*rdd-73847* host = ip-10-1-1-25.ec2.internal Spark streaming is configured with a microbatch interval of 30 seconds, checkpoint interval of 120 seconds, and cleaner.ttl of 28800 (8 hours), but as far as I can tell, this TTL only affects metadata cleanup interval. RDDs seem to be deleted every 4-5 minutes after being checkpointed. Running on top of Spark 1.5.1. Questions: - How is checkpoint deletion metadata saved so that in case of a driver restart the new driver does not read invalid metadata? Is there an interval between the point when the checkpoint data is deleted and this information is logged? - Why does Spark try to load data checkpointed 4-5 minutes in the past, given the fact checkpoint interval is 120 seconds and thus 5 minute old data is stale? There should be a newer checkpoint. - Would the memory management in Spark 2.0 handle this differently? Since we have not been able to reproduce the issue outside production environments, it might be useful to know in advance if there have been changes in this area. This issue is constantly causing serious data loss in production environments, I'd appreciate any assistance with it. -- View this message in context: http://apache-spark-developers-list.1001551.n3.nabble.com/Spark-Streaming-deletes-checkpointed-RDD-then-tries-to-load-it-after-restart-tp19409.html Sent from the Apache Spark Developers List mailing list archive at Nabble.com. --------------------------------------------------------------------- To unsubscribe e-mail: dev-unsubscr...@spark.apache.org
