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https://issues.apache.org/jira/browse/HDFS-8277?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17508550#comment-17508550
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tomscut commented on HDFS-8277:
-------------------------------
We have the same problem, see HDFS-16505.
Because DFSAdmin is sequential, if we use Standby Read, the configuration order
is:
nn1 -> OBN1
nn2 -> OBN2
nn3 -> OBN3
nn4 -> ANN
nn5 -> SNN
So let's say that when we *enter* Safemode, namenodes are normal. So all five
nodes are in Safemode.
Then, OBN1 goes down, we execute *leave* Safemode, and we can't exit Safemode
normally.
We have to run this command one by one: hdfs dfsadmin -fs
hdfs://<NN-IP>:<RPCPORT> -safemode leave .
> Safemode enter fails when Standby NameNode is down
> --------------------------------------------------
>
> Key: HDFS-8277
> URL: https://issues.apache.org/jira/browse/HDFS-8277
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: ha, namenode
> Affects Versions: 2.6.0
> Environment: HDP 2.2.0
> Reporter: Hari Sekhon
> Assignee: Jianfei Jiang
> Priority: Major
> Attachments: HDFS-8277-safemode-edits.patch, HDFS-8277.patch,
> HDFS-8277_1.patch, HDFS-8277_2.patch, HDFS-8277_3.patch, HDFS-8277_4.patch,
> HDFS-8277_5.patch
>
>
> HDFS fails to enter safemode when the Standby NameNode is down (eg. due to
> AMBARI-10536).
> {code}hdfs dfsadmin -safemode enter
> safemode: Call From nn2/x.x.x.x to nn1:8020 failed on connection exception:
> java.net.ConnectException: Connection refused; For more details see:
> http://wiki.apache.org/hadoop/ConnectionRefused{code}
> This appears to be a bug in that it's not trying both NameNodes like the
> standard hdfs client code does, and is instead stopping after getting a
> connection refused from nn1 which is down. I verified normal hadoop fs writes
> and reads via cli did work at this time, using nn2. I happened to run this
> command as the hdfs user on nn2 which was the surviving Active NameNode.
> After I re-bootstrapped the Standby NN to fix it the command worked as
> expected again.
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