Hi, Recently, lots of developments and applications were done and deployed based on consuming HBase Rest API. For Restful servlet (org.apache.hadoop.hbase.rest.Main (0.94), org.apache.hadoop.hbase.rest.RESTServer (trunk)) on Jetty, we need to first explicitly start the service (% ./bin/hbase-daemon.sh start rest -p 8000 ) for application running. Here is a scenario, sometimes, HBase cluster are stopped/started for maintanence, but rest is a seperated standalone process, which binds the HBaseAdmin at construction method. HBase stop/start cause this binding lost for existing rest servlet. Rest servlet still exist to trying on old bound HBaseAdmin until a long time duration later with an "Unavailable" caught via an IOException caught in such as RootResource.
Is there any JIRA discussion on this with some questions like: - could we pairwise the HBase service with HBase rest service with some start/stop options? since seems no reason to still keep the rest servlet process after HBase stopped? When HBase restarts, original rest service could not resume to bind to the new HBase service via its old HBaseAdmin reference? So may we stop the rest when hbase stopped, or even if hbase was killed by acident, restart hbase with rest option could detect the old rest process, kill it and start to bind a new one? >From this point of view, application rely on rest api in previous scenario could immediately detect it when setting up http connection session instead of wasting a long time to fail back from IOException with "Unavailable" from rest servlet. -- Best Regards, Julian
