On Mon, Jan 8, 2018 at 11:28 PM, Aaron T. Myers <a...@apache.org> wrote:
> Thanks a lot for the response, Larry. Comments inline. > > On Mon, Jan 8, 2018 at 6:44 PM, larry mccay <lmc...@apache.org> wrote: > >> Question... >> >> Can this be addressed in some way during or before upgrade that allows it >> to only affect new installs? >> Even a config based workaround prior to upgrade might make this a change >> less disruptive. >> >> If part of the upgrade process includes a step (maybe even a script) to >> set the NN RPC port explicitly beforehand then it would allow existing >> deployments and related clients to remain whole - otherwise it will uptake >> the new default port. >> > > Perhaps something like this could be done, but I think there are downsides > to anything like this. For example, I'm sure there are plenty of > applications written on top of Hadoop that have tests which hard-code the > port number. Nothing we do in a setup script will help here. If we don't > change the default port back to what it was, these tests will likely all > have to be updated. > > I may not have made my point clear enough. What I meant to say is to fix the default port but direct folks to explicitly set the port they are using in a deployment (the current default) so that it doesn't change out from under them - unless they are fine with it changing. > >> Meta note: we shouldn't be so pedantic about policy that we can't back >> out something that is considered a bug or even mistake. >> > > This is my bigger point. Rigidly adhering to the compat guidelines in this > instance helps almost no one, while hurting many folks. > > We basically made a mistake when we decided to change the default NN port > with little upside, even between major versions. We discovered this very > quickly, and we have an opportunity to fix it now and in so doing likely > disrupt very, very few users and downstream applications. If we don't > change it, we'll be causing difficulty for our users, downstream > developers, and ourselves, potentially for years. > Agreed. > > Best, > Aaron >
