Ben, I understand why you question that libprocess should log starting from a specific level. I think it is not quite illogical for a library to use lower priority levels. I can see this change being helpful for any user of libprocess, not just Mesos.
On Mon, Oct 9, 2017 at 6:34 PM, Benjamin Mahler <bmah...@apache.org> wrote: > > > > 2. Changing the libprocess verbose logs to start at level 3. Not just > > due to an ordering between Mesos and libprocess logs, but also because > > libprocess is a low-level library. > > > 2. is the part that is concerning. It seems arbitrary to me to have > libprocess start at a particular level since it's a library. Can you make > it a configuration option as I mentioned earlier? > > The /logging integration for per-module logging sounds great! > > On Mon, Oct 9, 2017 at 11:02 AM, Armand Grillet <agril...@mesosphere.io> > wrote: > > > Thanks for your input Benjamin. After having looked at per-module verbose > > level, here are the changes I would like to apply: > > > > 1. Changing the Mesos common events verbose logs so that they use > > VLOG(2) instead of 1. The original commit > > https://github.com/apache/meso > > s/commit/fa6ffdfcd22136c171b43aed2e7949a07fd263d7 > > <https://github.com/apache/mesos/commit/ > fa6ffdfcd22136c171b43aed2e7949 > > a07fd263d7> > > that > > started using VLOG(1) for the allocator does not state why this level > > was > > chosen and the periodic messages such as "No allocations performed" > > should > > be displayed at a higher level to simplify debugging. > > 2. Changing the libprocess verbose logs to start at level 3. Not just > > due to an ordering between Mesos and libprocess logs, but also because > > libprocess is a low-level library. > > 3. Adding support for the GLOG vmodule flag and add it as an option in > > /toggle/logging (as suggested in https://issues.apache.org/j > > ira/browse/MESOS-5784). However, this would not allow us to have a > > per-component logging verbosity control that should be added > afterwards. > > > > > > 2017-10-07 1:47 GMT+02:00 Benjamin Mahler <bmah...@apache.org>: > > > > > It seems unfortunate to establish an ordering between different > > component's > > > verbosity levels, how is libprocess to know which level to start at? I > > > suppose you can tell it, but it's not clear that the first level of > > > verbosity in libprocess should come after the max level of verbosity in > > > mesos. > > > > > > This seems to surface a need for per-module logging verbosity control. > > Have > > > you looked into the '--vmodule' flag? > > > > > > On Wed, Oct 4, 2017 at 12:59 PM, Armand Grillet < > agril...@mesosphere.io> > > > wrote: > > > > > > > Hi all, > > > > > > > > We currently use three levels of verbose logging via the VLOG macro. > I > > > > propose to add two levels and change how we use the current ones to > > make > > > > debugging easier for Mesos developers. > > > > > > > > The current situation is: > > > > > > > > - VLOG(1) is used for Mesos and libprocess events such as the > > > > admission of an agent by a master. It is also used for a few Mesos > > > > common > > > > events, e.g. the allocation of resources on an agent. > > > > - VLOG(2) is used for Mesos and libprocess common events, e.g. the > > > > reception of an offer by a Mesos scheduler. > > > > - VLOG(3) is used when a Mesos scheduler process saves the PID > > > > associated with each slave and for libprocess events related to > > > timers, > > > > clocks, and waiter processes. > > > > > > > > As an example, running GLOG_v=<level> ./mesos-tests --gtest_filter=" > > > > OversubscriptionTest.UpdateAllocatorOnSchedulerFailover" --verbose > > > > returns: > > > > > > > > - 212 lines of logs with level = 1. > > > > - 695 lines of logs with level = 2. > > > > - 782 lines of logs with level = 3. > > > > > > > > The logs at level 2 are quite noisy. This is mainly due to the number > > of > > > > messages regarding libprocess recurring events such as process > > > resumptions: > > > > https://github.com/apache/mesos/blob/d863620e5cb82b7f22cade0da0a0d1 > > > > 8afbdf9136/3rdparty/libprocess/src/process.cpp#L3245 > > > > > > > > To improve the situation, I suggest having five levels: > > > > > > > > - VLOG(1), used for Mesos events. > > > > - VLOG(2), used for Mesos common/recurring events. > > > > - VLOG(3), used for libprocess events. > > > > - VLOG(4), used for libprocess common/recurring events. > > > > - VLOG(5), used for libprocess events related to timers, clocks, > and > > > > waiter processes. > > > > > > > > This change would allow us to read the Mesos verbose logs without > > having > > > to > > > > see the ones concerning libprocess, a use case that seems reasonable > > for > > > > Mesos developers. The new log levels would make it possible to have > the > > > > same logs as before when necessary. > > > > > > > > What do you think about this? Please feel free to share your thoughts > > and > > > > comments. > > > > > > > > -- > > > > Armand Grillet > > > > Software Engineer, Mesosphere > > > > > > > > > > > > > > > -- > > Armand Grillet > > Software Engineer, Mesosphere > > >
