[Cluster-devel] [RFC] Configuring logging system for master
Lon Hohberger
lhh at redhat.com
Tue Jun 10 13:19:03 UTC 2008
On Mon, 2008-06-02 at 12:05 +0200, Fabio M. Di Nitto wrote:
> Hi guys,
>
> there has been a halt on porting daemons to the new logsys library because
> there is a small disagreement on how the configuration bits should be
> reflected in cluster.conf (or equivalent).
>
> It's about time to take a decision to complete this transition.
>
> The 2 current methods are:
>
> 1) as implemented by cman:
>
> <cluster>
> <logging to_stderr="on" debug="on">
> <logger_subsys subsys="CMAN" syslog_facility=".." debug="on"/>
> <logger_subsys subsys="CCS" syslog_facility=".." debug="on"/>
> </logging>
> </cluster>
>
> 2) as originally implemented by qdisk and rgmanager (and later by ccs):
>
> <cluster>
> <quorumd log_level="..." log_facility="...">
> <rm log_level="..." log_facility="...">
> </cluster>
>
> The 2 philosophies behind are fairly clear:
>
> #1 consider the logging as a subsystem on its own that should be
> configured as standalone bit.
>
> #2 consider the logging as part of the subsystem configuration bits.
>
> All the people involved in the discussion so far (Chrissie, Lon and me)
> don't really have a strong opinion on which way should be taken, but a
> decision needs to be taken. Both ways have pro and cons...
>
> #1
>
> Pros: it's elegant to see the configuration all in one place. Move away
> from subsystem keys to global ones. If the subsystem is an openais plugin,
> openais executive will do all the parsing for us with no code changes.
>
> Cons: the association between subystem and config is not immediate. Users
> need to remember mappings (CMAN == cman, CCS = ccs, etc.) that are not
> 1:1. There is no finegraned tuning for logging level.
>
> #2
>
> Pros: association is immediate between config and subsystem. 3 systems
> already use it.
> Cons: it's not centralized.
I maintain at least most of those 3. I agree that it's better from a
user-experience point of view (daemon X logs HERE), but it's also
fundamentally different from how liblogsys works, and doesn't easily
allow for sub-subsystem configuration.
For example, openais has several subsystems which (I think) can be
configured independently, but are all wrapped up in to one daemon.
Modeling this with the model rgmanager/qdiskd/etc. use is difficult.
I am having difficulty forming a clear opinion.
-- Lon
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