[HDFS-2983] Relax the build version check to permit rolling upgrades within a release

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha
• Fix Version/s: 2.0.0-alpha
• Target Version/s: 2.0.0-alpha
• Hadoop Flags: Reviewed
• Assignee: Aaron Myers
• Reporter: Eli Collins
• Created: 22/Feb/12 18:17
• Updated: 28/Sep/15 20:58
• Resolved: 12/Apr/12 03:56

Description

Currently the version check for DN/NN communication is strict (it checks the exact svn revision or git hash, Storage#getBuildVersion calls VersionInfo#getRevision), which prevents rolling upgrades across any releases. Once we have the PB-base RPC in place (coming soon to branch-23) we'll have the necessary pieces in place to loosen this restriction, though perhaps it takes another 23 minor release or so before we're ready to commit to making the minor versions compatible.

Issue Links

• breaks: HDFS-3260 TestDatanodeRegistration should set minimum DN version in addition to minimum NN version
• is blocked by: HDFS-3202 NamespaceInfo PB translation drops build version
• is related to: MAPREDUCE-4150 Versioning and rolling upgrades for MR2
• is related to: HADOOP-8968 Add a flag to completely disable the worker version check
• relates to: HADOOP-702 DFS Upgrade Proposal
• relates to: HADOOP-8209 Add option to relax build-version check for branch-1
• relates to: HDFS-3245 Add metrics and web UI for cluster version summary