[ 
https://issues.apache.org/jira/browse/HDFS-13132?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16492351#comment-16492351
 ] 

genericqa commented on HDFS-13132:
----------------------------------

| (x) *{color:red}-1 overall{color}* |
\\
\\
|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue}  0m  
0s{color} | {color:blue} Docker mode activated. {color} |
| {color:red}-1{color} | {color:red} patch {color} | {color:red}  0m  6s{color} 
| {color:red} HDFS-13132 does not apply to HDFS-7240. Rebase required? Wrong 
Branch? See https://wiki.apache.org/hadoop/HowToContribute for help. {color} |
\\
\\
|| Subsystem || Report/Notes ||
| JIRA Issue | HDFS-13132 |
| JIRA Patch URL | 
https://issues.apache.org/jira/secure/attachment/12910155/HDFS-13132-HDFS-7240.002.patch
 |
| Console output | 
https://builds.apache.org/job/PreCommit-HDFS-Build/24312/console |
| Powered by | Apache Yetus 0.8.0-SNAPSHOT   http://yetus.apache.org |


This message was automatically generated.



> Ozone: Handle datanode failures in Storage Container Manager
> ------------------------------------------------------------
>
>                 Key: HDFS-13132
>                 URL: https://issues.apache.org/jira/browse/HDFS-13132
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: ozone
>    Affects Versions: HDFS-7240
>            Reporter: Mukul Kumar Singh
>            Assignee: Shashikant Banerjee
>            Priority: Major
>             Fix For: HDFS-7240
>
>         Attachments: HDFS-13132-HDFS-7240.001.patch, 
> HDFS-13132-HDFS-7240.002.patch
>
>
> Currently SCM receives heartbeat from the datanodes in the cluster receiving 
> container reports. Apart from this Ratis leader also receives the heartbeats 
> from the nodes in a Raft ring. The ratis heartbeats are at a smaller interval 
> (500 ms) whereas SCM heartbeats are at (30s), it is thereby considered safe 
> to assume that a datanode is really lost when SCM missed heartbeat from such 
> a node.
> The pipeline recovery will follow the following steps
> 1) As noted earlier, SCM will identify a dead DN via the heartbeats. Current 
> stale interval is (1.5m). Once a stale node has been identified, SCM will 
> find the list of containers for the pipelines the datanode was part of.
> 2) SCM sends close container command to the datanodes, note that at this 
> time, the Ratis ring has 2 nodes in the ring and consistency can still be 
> guaranteed by Ratis.
> 3) If another node dies before the close container command succeeded, then 
> ratis cannot guarantee consistency of the data being written/ close 
> container. The pipeline here will be marked in a inconsistent state.
> 4) Closed container will be replicated via the close container replication 
> protocol.
> If the dead datanode comes back, as part of the re-register command, SCM will 
> ask the Datanode to format all the open containers.
> 5) Return the healthy nodes back to the free node pool for the next pipeline 
> allocation
> 6) Read operation to close containers will succeed however read operation to 
> a open container on a single node cluster will be disallowed. It will only be 
> allowed under a special flag aka ReadInconsistentData flag.
> This jira will introduce the mechanism to identify and handle datanode 
> failure.
> However handling of a) 2 nodes simultaneously and b) Return the nodes to 
> healthy state c) allow inconsistent data reads and d) purging of open 
> container on a zombie node will be done as part of separate bugs.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org

Reply via email to