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Arpit Agarwal updated HDFS-5454: -------------------------------- Attachment: HDFS-5454.02.patch Updated patch. > DataNode UUID should be assigned prior to FsDataset initialization > ------------------------------------------------------------------ > > Key: HDFS-5454 > URL: https://issues.apache.org/jira/browse/HDFS-5454 > Project: Hadoop HDFS > Issue Type: Sub-task > Components: datanode > Affects Versions: 3.0.0 > Reporter: Eric Sirianni > Priority: Minor > Attachments: HDFS-5454.01.patch, HDFS-5454.02.patch > > > The DataNode's UUID ({{DataStorage.getDatanodeUuid()}} field) is NULL at the > point where the {{FsDataset}} object is created ({{DataNode.initStorage()}}. > As the {{DataStorage}} object is an input to the {{FsDataset}} factory > method, it is desirable for it to be fully populated with a UUID at this > point. In particular, our {{FsDatasetSpi}} implementation relies upon the > DataNode UUID as a key to access our underlying block storage device. > This also appears to be a regression compared to Hadoop 1.x - our 1.x > {{FSDatasetInterface}} plugin has a non-NULL UUID on startup. I haven't > fully traced through the code, but I suspect this came from the > {{BPOfferService}}/{{BPServiceActor}} refactoring to support federated > namenodes. > With HDFS-5448, the DataNode is now responsible for generating its own UUID. > This greatly simplifies the fix. Move the UUID check/generation in from > {{DataNode.createBPRegistration()}} to {{DataNode.initStorage()}}. This more > naturally co-locates UUID generation immediately subsequent to the read of > the UUID from the {{DataStorage}} properties file. > {code} > private void initStorage(final NamespaceInfo nsInfo) throws IOException { > // ... > final String bpid = nsInfo.getBlockPoolID(); > //read storage info, lock data dirs and transition fs state if necessary > storage.recoverTransitionRead(this, bpid, nsInfo, dataDirs, startOpt); > > // SUGGESTED NEW PLACE TO CHECK DATANODE UUID > checkDatanodeUuid(); > // ... > } > {code} -- This message was sent by Atlassian JIRA (v6.1.4#6159)