[Linux-ha-dev] Clone Notifications
lmb at suse.de
Wed Aug 10 04:40:40 MDT 2005
On 2005-08-10T12:15:57, "Andrew Beekhof (GMail)" <beekhof at gmail.com> wrote:
> sorry, "is being started" or "was started". the tense being
> inferred by the type of notification "pre" or "post".
> if the start fails you wont get the post notification
> you'll next get a pre-notification for a stop
> if some clones started and some didnt, the ones that did start will
> next appear as stable <peer> entries.
> does this answer your comments below?
> >I'm not convinced we need to tell them about unchanging things. For
> >example, the above makes sense whether or not :1 was already
> >running on
> >node1 or not - we tell it that we intend that it will be started
> >afterwards, which is probably fine.
> i dont think thats a good idea
> how do you then differentiate between :1 starting and :1 already
> being active?
> i can imagine different things happening in the different cases
> I'd instead go with CLONES_IS_ACTIVE="1"
ACTIVE bad. STARTED good. (Then we can add promoted/demoted later.)
> >Now I'm also a huge fan of conveying more information than
> >necessay ;-).
> >Hm. We could list those in _STOPPED, _STARTED, _PROMOTED, to
> >indicate we
> >ain't doing anything with them, but leave them in whatever state they
> >are in
> started/stopped is fine.
> not sure about promoted yet - i'll defer that until master/slave gets
That was just looking forward ;-)
> >(and in a post-notification, that would of course imply that
> >everything would be in _STARTED, for example).
> i dont think thats a good idea, then the RA no longer knows what we did
> again, i can imagine there might be different logic for nodes that
> versus nodes that were already started/stopped
> or maybe include them in both lists, though it can easily be inferred
Well, OK, I have this narrow view of the GFS/drbd/OCFS2 resources which
don't care about this distinction. But yes, two lists probably makes
more sense, as I also elaborated below in the example...
> >(And, of course, for "_STOPPED", there'd be no _NODE_ entry. Or one
> >listing them as "NULL". ;-)
> as per started
"started"? Dear sir, for sure "started" will have to have a NODE entry,
because it is certainly running on a given node.
> >Do we want to head down the path and list _FAILED too? ie, which
> >have failed on which nodes? We have the info, just not sure whether we
> >want to / can easily expose it.
> i would say "not at this time"
OK. Just asking.
Lars Marowsky-Brée <lmb at suse.de>
High Availability & Clustering
SUSE Labs, Research and Development
SUSE LINUX Products GmbH - A Novell Business -- Charles Darwin
"Ignorance more frequently begets confidence than does knowledge"
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