[HDFS-9788] Incompatible tag renumbering in HeartbeatResponseProto

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 2.8.0
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Component/s: rolling upgrades
• Target Version/s: 2.8.0
• Assignee: Andrew Wang
• Reporter: Andrew Wang
• Created: 10/Feb/16 21:02
• Updated: 30/Aug/16 01:19
• Resolved: 10/Feb/16 23:27

Description

The HDFS-9426 patches for branch-2.7 and branch-2 used different tag numbers for rollingUpgradeStatusV2 in HeartbeatResponseProto:

trunk/branch-2:

message HeartbeatResponseProto {
  repeated DatanodeCommandProto cmds = 1; // Returned commands can be null
  required NNHAStatusHeartbeatProto haStatus = 2;
  optional RollingUpgradeStatusProto rollingUpgradeStatus = 3;
  optional uint64 fullBlockReportLeaseId = 4 [ default = 0 ];
  optional RollingUpgradeStatusProto rollingUpgradeStatusV2 = 5;
}

branch-2.7:

message HeartbeatResponseProto {
  repeated DatanodeCommandProto cmds = 1; // Returned commands can be null
  required NNHAStatusHeartbeatProto haStatus = 2;
  optional RollingUpgradeStatusProto rollingUpgradeStatus = 3;
  optional RollingUpgradeStatusProto rollingUpgradeStatusV2 = 4;
}

This breaks rolling upgrade between 2.7 and a future 2.8. We need to renumber the tags to preserve wire compatibility.