Apache Hadoop 3.2.1 Release Notes

These release notes cover new developer and user-facing incompatibilities, important issues, features, and major improvements.

support -p and -P for bridge type network;

In progress upgrade status may show READY state sooner than actual upgrade operations. External caller to upgrade API is recommended to wait minimum 30 seconds before querying yarn app -status.

Improve transient container status accuracy for upgrade.

NameNodes rely on independent block token key ranges to communicate block token identities to DataNodes and clients in a way that does not create conflicts between the tokens issued by multiple NameNodes. HDFS-6440 introduced the potential for overlaps in key ranges; this fixes the issue by creating 64 possible key ranges that NameNodes assign themselves to, allowing for up to 64 NameNodes to run safely. This limitation only applies within a single Namespace; there may be more than 64 NameNodes total spread among multiple federated Namespaces.

During a rolling upgrade from Hadoop 2.x to 3.x, NameNode cannot persist erasure coding information, and therefore a user cannot start using erasure coding feature until finalize is done.

Application Timeline Server v2 is ready for production. It is GA from 3.2.1 release on wards.