The motivation for "dynamic" quota/weights was that we wanted operators to be able to change these without restarting (all) masters. That means you'd update these values via operator endpoints, and if you're doing that, then the flag values become outdated/irrelevant, and we must persist these values somewhere that they can be restored on master failover (i.e. registry). However, we have kept the flags around for bootstrapping and backwards compatibility.
Other flags that could benefit from dynamic updates (without restarting masters): - acls - credentials - firewall_rules - rate_limits - ping timeouts - max completed frameworks/tasks - whitelist (actually reloads the file every so often) On Fri, Jun 10, 2016 at 4:29 AM, Neil Conway <neil.con...@gmail.com> wrote: > Makes sense: arguably you could say that "quota" and "weights" are > part of the master's (mutable) "state", not its "configuration", which > is largely immutable. > > Another distinction is that some configuration flags control behavior > that doesn't need to be consistent between master replicas (e.g., > "--ip", "--port", "--advertise-ip", "--advertise-port", "--hostname", > "--hostname-lookup", "--quiet", "--log_dir", "--modules_dir", > "--work_dir", etc). > > Neil > > On Fri, Jun 10, 2016 at 3:52 AM, Benjamin Mahler <bmah...@apache.org> > wrote: > > I'm curious to hear thoughts on the distinction between using flags and > > persisting in the registry for master configuration. This topic had come > up > > in a discussion and our current choices are intuitive but the criteria > were > > not immediately obvious. > > > > Two cases seem interesting to me: > > > > (1) Quota. > > (2) Weights. > > > > These are configuration, but we persist them in the registry. Why is > that? > > > > My intuition is that they reflect the organizational aspects of the > > workloads that are running and so we expect administrators and (most > > importantly!!) tooling to be view and modify these over time. > > > > Timeouts, work directories, etc, on the other hand, are rarely modified > and > > require initial values. There are also sane defaults for these that will > > work for most users. > > > > Thought this might be helpful for others that may wonder about this. Let > me > > know if there are any other important criteria that I've missed. > > > > Ben >
