项目场景:

最近实时平台flink任务频繁失败,报检查点方面的错误,最近集群的hdfs也经常报警:运行状况不良,不知道是否和该情况有关,我的状态后端位置是hdfs,废话不多说,干货搞起来~

问题描述

日志中报错如下:

2022-07-16 06:26:46,566 INFO org.apache.flink.runtime.checkpoint.CheckpointCoordinator [] - Checkpoint 670223 of job 61103d713243c4a71befb436fa3f32ee expired before completing.

2022-07-16 06:26:46,571 INFO org.apache.flink.runtime.jobmaster.JobMaster [] - Trying to recover from a global failure.

org.apache.flink.util.FlinkRuntimeException: Exceeded checkpoint tolerable failure threshold.

at org.apache.flink.runtime.checkpoint.CheckpointFailureManager.handleCheckpointException(CheckpointFailureManager.java:98) ~[flink-dist_2.11-1.13.1.jar:1.13.1]

at org.apache.flink.runtime.checkpoint.CheckpointFailureManager.handleJobLevelCheckpointException(CheckpointFailureManager.java:67) ~[flink-dist_2.11-1.13.1.jar:1.13.1]

at org.apache.flink.runtime.checkpoint.CheckpointCoordinator.abortPendingCheckpoint(CheckpointCoordinator.java:1934) ~[flink-dist_2.11-1.13.1.jar:1.13.1]

at org.apache.flink.runtime.checkpoint.CheckpointCoordinator.abortPendingCheckpoint(CheckpointCoordinator.java:1906) ~[flink-dist_2.11-1.13.1.jar:1.13.1]

at org.apache.flink.runtime.checkpoint.CheckpointCoordinator.access$600(CheckpointCoordinator.java:96) ~[flink-dist_2.11-1.13.1.jar:1.13.1]

at org.apache.flink.runtime.checkpoint.CheckpointCoordinator$CheckpointCanceller.run(CheckpointCoordinator.java:1990) ~[flink-dist_2.11-1.13.1.jar:1.13.1]

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_201]

at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_201]

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) ~[?:1.8.0_201]

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) ~[?:1.8.0_201]

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[?:1.8.0_201]

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[?:1.8.0_201]

at java.lang.Thread.run(Thread.java:748) ~[?:1.8.0_201]

注意:

在报Exceeded checkpoint tolerable failure threshold.错误的之前,是先报的是Checkpoint expired before completing.大概意思是检查点在完成前过期了。

解决方案:

这个错误也是头一次见,更让我好奇的是报这个错误的时间点大概差不多(每两天大概报一次,早晨6点多)。

最开始调整了检查点的频率(5s -> 10s)和任务重启间隔(5s -> 30s),以为频率太快了,但调整后并没能解决该问题。 后来又将jobmanager和taskmanager运行内存调大,但也没能解决…

通过查找flink检查点相关配置,发现了配置项TolerableCheckpointFailureNumber即可容忍检查点失败次数的配置,默认值为0表示不允许容忍任何检查点失败。 报的错就是超过检查点可容忍失败阈值,试试观察观察再说,因此在程序里加上了这个配置。

//设置可容忍的检查点失败数,默认值为0表示不允许容忍任何检查点失败

env.getCheckpointConfig().setTolerableCheckpointFailureNumber(2);

配置说明:

限制的是最大可容忍的连续失败checkpoint计数 continuousFailureCounter,例如将tolerableCheckpointFailureNumber设置成3,连续失败3次,continuousFailureCounter会累计到3,作业就会尝试重启。如果中间有一个checkpoint成功了,continuousFailureCounter 就会重置为零。

按之前的规律第二天任务就得报这个错误失败了,查看flink任务web界面,任务正常,但检查点确实失败过一次,也是大概那个时间失败的,失败原因和之前一样Checkpoint expired before completing.

说明该配置对报错的解决有效,问题解决!!!

记得点赞收藏奥,后续遇到问题会持续更新,关注不迷路~

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