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Patrick Kling updated HADOOP-7001: ---------------------------------- Attachment: HADOOP-7001.4.patch Incorporated Todd's comments on the review board. - Added unit tests for ReconfigurationUtil.getChangedProperties, Reconfigurable interface methods and cross-thread visibility of configuration changes. - Added proper escaping to servlet. - Removed synchronization from Configuration methods that were already protected by synchronization of getProps(). In this revision, I have only added synchronization to the setter methods. - Changed getReconfigurableProperties to return Collection rather than List. - Fixed typo. - Removed commented-out code. - Removed unnecessary imports. > Allow configuration changes without restarting configured nodes > --------------------------------------------------------------- > > Key: HADOOP-7001 > URL: https://issues.apache.org/jira/browse/HADOOP-7001 > Project: Hadoop Common > Issue Type: Task > Reporter: Patrick Kling > Assignee: Patrick Kling > Attachments: HADOOP-7001.2.patch, HADOOP-7001.3.patch, > HADOOP-7001.4.patch, HADOOP-7001.patch, reconfigurable.patch > > > Currently, changing the configuration on a node (e.g., the name node) > requires that we restart the node. We propose a change that would allow us to > make configuration changes without restarting. Nodes that support > configuration changes at run time should implement the following interface: > interface ChangeableConfigured extends Configured { > void changeConfiguration(Configuration newConf) throws > ConfigurationChangeException; > } > The contract of changeConfiguration is as follows: > The node will compare newConf to the existing configuration. For each > configuration property that is set to a different value than in the current > configuration, the node will either adjust its behaviour to conform to the > new configuration or throw a ConfigurationChangeException if this change is > not possible at run time. If a configuration property is set in the current > configuration but is unset in newConf, the node should use its default value > for this property. After a successful invocation of changeConfiguration, the > behaviour of the configured node should be indistinguishable from the > behaviour of a node that was configured with newConf at creation. > It should be easy to change existing nodes to implement this interface. We > can start by throwing the exception for all changes and then gradually start > supporting more and more changes at run time. (We might even consider > replacing Configured with ChangeableConfigured entirely, but I think the > proposal above afford greater flexibility). -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.