Help Center/ MapReduce Service/ Component Operation Guide (Paris Region)/ Using MapReduce/ Common Issues About MapReduce/ Why Cannot HDFS_DELEGATION_TOKEN Be Found in the Cache?
Updated on 2022-02-22 GMT+08:00
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Why Cannot HDFS_DELEGATION_TOKEN Be Found in the Cache?

Question

In security mode, why delegation token HDFS_DELEGATION_TOKEN is not found in the cache?

Answer

In MapReduce, by default HDFS_DELEGATION_TOKEN will be canceled after the job completion. So if the token has to be re- used for the next job then the token will not be found in the cache.

To re-use the same token in subsequent job set the below parameter for the MR job configuration. When it is false the user can re-sue the same token.

jobConf.setBoolean("mapreduce.job.complete.cancel.delegation.tokens", false);