On Fri, Jul 23, 2010 at 8:16 AM, Mark Laffoon <[email protected]> wrote: > I have a couple noobish questions about the servlet container. > > 1. As I understand it from reading docs and poking around in the code > hadoop and hbase both use an embedded jetty instance to host their admin > pages. >
Yes > 2. If I have hadoop master and hbase master running on the same machine, > does that mean I have two jetty instances instantiated? > Yes. > 2a. What hadoop and hbase processes use an embedded jetty? Obviously > namenode, hbase master, and jobtracker. What about regionserver, > tasktracker? > The regionserver yes, the tasktracker does too at least to transfer files during MR (last I checked). The datanode doesn't have an instance. > 3. Any idea what the approximate footprint of an embedded jetty instance > is? > Guessing, I'd say its "small" > 4. If I have a servlet container (jetty, tomcat, whatever) running on the > machine for other reasons, how tough is it to get hadoop and hbase to use > it instead of the embedded jetty? > We've not done the WAR packaging. The pieces are all there -- a web.xml, etc., see hbase-webapps when you download a binary -- so shouldn't be hard bundling them up. Hard part, as for any WAR, is configuring it. HBase/Hadoop config is in the conf directory. You'd need to get this conf on the webapp CLASSPATH so it was pointing at proper cluster. Historically, IIUC hadoop/hbase doesn't go all the way and make a WAR because wants to ship w/ precompiled jsps... so on deploy you can get away w/ JRE rather than JDK (Not so sure how this holds up any more). > > > This boils down to: I'm going to have various processes using a servlet > container on my servers. Should I worry about trying to share the same > container across all the hadoop/hbase processes as well? > Unless a compelling reason, I'd say avoid the unification. Hadoop/HBase are non-standard in their use of java technologies. You'll be surprised at every turn. It'd be time sink for little benefit. Others might have different opinions. St.Ack > > > Thanks, > > Mark > >
