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From dlmar...@comcast.net
Subject Re: Planning for (eventual) removal of instance.dfs.{uri,dir}
Date Thu, 11 Dec 2014 16:17:14 GMT
It has been my experience that testing is always required when upgrading a major component.
With the vote to adopt semver, our users will have more of a guarantee that their applications
will work through patch and minor version upgrades. It might be useful though to have a document
like CHANGES, but contain the items that have been removed in the major release and a note
on what (if anything) is replacing the removed function. 


----- Original Message -----

From: "Jeremy Kepner" <kepner@ll.mit.edu> 
To: dev@accumulo.apache.org 
Sent: Thursday, December 11, 2014 10:44:21 AM 
Subject: Re: Planning for (eventual) removal of instance.dfs.{uri,dir} 

When we remove functions, do we have any official guidance to our users who may 
have built applications that use those functions? 

Right now, the official position is that the Accumulo developers can remove 
as they see fit. However, this provides no guidance to users as to what 
they are suppose to do? As it stands, our guidance is that they have the following choices:


(0) Diligently watch the Accumulo e-mail list and aggressively weigh in on 
any vote to remove functions that may impact them. 

(1) Find someone to modify the original source code of their applications, 
build it, and *re-verify* the application. I emphasise the re-verify because 
that is usually the most costly part of the process that often won't get approved 
by management. 

(2) Don't upgrade Accumulo. 





On Thu, Dec 11, 2014 at 10:03:56AM -0500, Christopher wrote: 
> Well, no, the database will start if we rely on instance.volumes, but we 
> may be unable to find files that have relative paths, if we incorrectly 
> assume /accumulo. Making it required is annoying if users don't have 
> relative paths. 
> 
> 
> -- 
> Christopher L Tubbs II 
> http://gravatar.com/ctubbsii 
> 
> On Thu, Dec 11, 2014 at 8:15 AM, <dlmarion@comcast.net> wrote: 
> 
> > How so? If someone upgrades from another version and is using a different 
> > dir, doesn't specify it in the configuration, and we assume /accumulo, then 
> > their database won't start. The other option, which may be safer than 
> > making any assumptions, is to make instance.volumes a required parameter 
> > with no defaults. 
> > 
> > ----- Original Message ----- 
> > 
> > From: "Christopher" <ctubbsii@apache.org> 
> > To: "Accumulo Dev List" <dev@accumulo.apache.org> 
> > Sent: Wednesday, December 10, 2014 11:51:39 PM 
> > Subject: Re: Planning for (eventual) removal of instance.dfs.{uri,dir} 
> > 
> > The URI is probably reasonable, but the dir is potentially problematic if 
> > you weren't using the default. 
> > 
> > 
> > -- 
> > Christopher L Tubbs II 
> > http://gravatar.com/ctubbsii 
> > 
> > On Wed, Dec 10, 2014 at 10:03 PM, dlmarion <dlmarion@comcast.net> wrote: 
> > 
> > > Looks like VolumeConfiguration falls back to fs.defaultFS for the uri and 
> > > /accumulo for the dir. You could remove both properties and still keep 
> > this 
> > > as the documented default behavior if instance.volumes is not specified. 
> > > 
> > > 
> > > 
> > > <div>-------- Original message --------</div><div>From: Christopher
< 
> > > ctubbsii@apache.org> </div><div>Date:12/10/2014 9:13 PM (GMT-05:00)

> > > </div><div>To: Accumulo Dev List <dev@accumulo.apache.org>

> > > </div><div>Cc: </div><div>Subject: Re: Planning for
(eventual) removal of 
> > > instance.dfs.{uri,dir} </div><div> 
> > > </div>My ACCUMULO-2589 branch in github ( 
> > > https://github.com/ctubbsii/accumulo/tree/ACCUMULO-2589) does have a 
> > > commit 
> > > that drops a bunch of stuff (which may or may not be accepted as is for 
> > > 2.0). The instance.dfs.{uri,dir} properties aren't so easy and require 
> > more 
> > > planning, because it's not just removing a property... it's also dealing 
> > > with updating internal data by making relative paths absolute. 
> > > 
> > > For what it's worth, I'm also looking at what changes if we drop Hadoop 1 
> > > support. 
> > > 
> > > As for the validation of config, I think we do a sanity check on startup 
> > > already, which we can always extend. Doesn't solve this issue, though. 
> > > 
> > > 
> > > -- 
> > > Christopher L Tubbs II 
> > > http://gravatar.com/ctubbsii 
> > > 
> > > On Wed, Dec 10, 2014 at 8:59 PM, dlmarion <dlmarion@comcast.net> wrote:

> > > 
> > > > We should schedule a bunch of deprecated things for removal in 2.0 to

> > > ease 
> > > > maintenance. Do we have a way to validate the site.xml and zookeeper 
> > > > settings before startup and fail with appropriate error message. 
> > > > 
> > > > 
> > > > 
> > > > <div>-------- Original message --------</div><div>From:
Christopher < 
> > > > ctubbsii@apache.org> </div><div>Date:12/10/2014 8:44 PM
(GMT-05:00) 
> > > > </div><div>To: Accumulo Dev List <dev@accumulo.apache.org>

> > > > </div><div>Cc: </div><div>Subject: Planning for
(eventual) removal of 
> > > > instance.dfs.{uri,dir} </div><div> 
> > > > </div>So, 
> > > > 
> > > > instance.volumes replaces instance.dfs.uri and instance.dfs.dir in 1.6.

> > > > But, what's our long-term plan for these? I ask, because we still have

> > > > internal code that uses instance.dfs.uri to resolve relative paths. 
> > > > 
> > > > Should we force these to be re-written at some point (maybe on upgrade

> > to 
> > > > 1.7)? Should we continue to support the deprecated properties 
> > > indefinitely 
> > > > and continue the lazy re-write-on-compact? Do we transition by 
> > requiring 
> > > > instance.volumes to specify the volumes, and only use the old 
> > properties 
> > > to 
> > > > resolve relative paths? 
> > > > 
> > > > My personal view is that we should provide an upgrade-prep/check tool

> > > prior 
> > > > to upgrade to 2.0, which checks and/or re-writes paths and verifies 
> > that 
> > > > instance.volumes is set. 
> > > > 
> > > > Does anybody have a different opinion on this? 
> > > > 
> > > > -- 
> > > > Christopher L Tubbs II 
> > > > http://gravatar.com/ctubbsii 
> > > > 
> > > 
> > 
> > 


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