On 9 October 2012 16:51, Shinichi Yamashita <shin1...@gmail.com> wrote:
> Hi Steve, > > Thank you for your reply. > > > > no, it's the Namenode and JobTracker that needs to be restarted; > > they are the bits that care where the boxes are. > > I confirmed it in my cluster, and I understood it as follows. > First, the resolved node information is recorded in ConcurrentHashMap. > Next same node toplogy decision, HashMap data is given priority to over a > script. > The HashMap data become invalid by restart of NameNode and JobTracker. > That's right. There's been lots of discussion on adding live topology resetting. There's also a large unfinished JIRA in my name to do better topology work in Hadoop 2, https://issues.apache.org/jira/browse/HADOOP-8231 Including the ability to do local checks of a topology script https://issues.apache.org/jira/browse/HADOOP-8232 Supporting topology dump and reset from any of the manager nodes would come after. -steve
