HDFS DELEGATION TOKEN can’t be found in cache

The problem can be appears in Hadoop’s NodeManager logs. Usually it means that NodeManager is trying to use an expired / not renewed HDFS delegation token. For example, you can face this error while app log aggregation process. The timeline is: Your application pass HDFS delegation token to the NodeManager through the ContainerLaunchContext class, because […]

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Resource changed on src filesystem

Full exception text: This can happen when some process overwrites application files in HDFS application directory while app is running. An example of the situation: You start app instance_1, which stores the distribution files in the hdfs://tmp/app folder. After a while you start the second instance_2 which stores the distribution files in the same HDFS […]

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Spark concurrent write to same HDFS path

The problem Sometimes you need to run such a scenario when several Spark tasks write data along the same path to HDFS. During the execution of tasks, you may encounter some errors: Suppose we have one Spark task, that writes to the hdfs://data/test directory. At runtime, Spark will make a temporary directory: hdfs://data/test/_temporary/0. There is […]

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