hadoop-yetus commented on a change in pull request #1196: HDDS-1881. Design doc: decommissioning in Ozone URL: https://github.com/apache/hadoop/pull/1196#discussion_r309212396
########## File path: hadoop-hdds/docs/content/design/decommissioning.md ########## @@ -0,0 +1,720 @@ +--- +title: Decommissioning in Ozone +summary: Formal process to shut down machines in a safe way after the required replications. +date: 2019-07-31 +jira: HDDS-1881 +status: current +author: Anu Engineer, Marton Elek, Stephen O'Donnell +--- + + +# Abstract + +The goal of decommissioning is to turn off a selected set of machines without data loss. It may or may not require to move the existing replicas of the containers to other nodes. + +There are two main classes of the decommissioning: + + * __Maintenance mode__: where the node is expected to be back after a while. It may not require replication of containers if enough replicas are available from other nodes (as we expect to have the current replicas after the restart.) + + * __Decommissioning__: where the node won't be started again. All the data should be replicated according to the current replication rules. + +Goals: + + * Decommissioning can be canceled any time + * The progress of the decommissioning should be trackable + * The nodes under decommissioning / maintenance mode should not been used for new pipelines / containers + * The state of the datanodes should be persisted / replicated by the SCM (in HDFS the decommissioning info exclude/include lists are replicated manually by the admin). If datanode is marked for decommissioning this state be available after SCM and/or Datanode restarts. Review comment: whitespace:end of line ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
