Re: [gomd-devel] <IRC> interesting IRC chat session about gomd...

[Gian Paolo Ghilardi]

Hi all.

First of all: CHPOX stuff will be implemented after the first pubblic beta
phase (we're not so far... ;) ).
Ok?


>
> read the mails+irc-log about auth + checkpointing and
> here are my comments.
>
> about the auth:
> I prefer the auth.conf for gomd for now
> (later we can see if we improve this)
> The feature should combine acl.conf + scx.conf
I prefer three separate files ({acl/scx/auth}.conf) because I dislike long
and difficult-to-be-read files like smb.conf.

>
> about the checkpointing:
> It is a vey good idea to add this feature to the gomd :) !
> The users will love it.
> I just think that automatically checkpointing the processes
> which needs most of the cpu will not work so well.
>
> Here are my thoughts about the chpox-support :
>
> 1) we need a register, unregister and list-register processes
>    register should automatically check the binary program
>    with ldd to find out which libraries needs to be added
>    to chpox before. -> even if it is a script to register it
>    needs some libs for e.g. bash
np.

>
> 2) unregister should unregister the process but not the libs
>    because they may be needed by other registered processes
ok.

>
> 3) the registration will use a dump-file with the process + pid
>    name to be sure to have unique names for the process dumps
dump format: [CMD]_[PID]_[DATE]_[TIME].dump Ok?
(ex for updatedb => "updatedb_2028_2003-09-25_23.07.dump")

>
> 4) if there are registered processes for checkpointing the gomd
>    should send the checkpoint signal to them in an intervall
>    (timeout can be static first, maybe later it would be nice if one
>    can configure it per process)
cmd format in future checkpoint.conf:
COMMAND:CHECKPOINT_INTERVAL
- COMMAND will be searched as in SCX stuff (if COMMAND =="sander" => every
sander command will be checkpointed).
- if (CHECKPOINT_INTERVAL == 0) => command won't be registered
Ok?

>
> 5) if a process is checkpointed the gomd should/must move its
>    dump file to a diffrent name containing a timestamp.
>    Otherwise the next checkpoint will overwrite the current dump file
>    even if the registered process is crashed but still alive. This will
>    make it "un-restorable"   -> so we need timestamps for each
>    checkpointed process-dump to be able to restore it at any given
>    time (any given time a checkpoint was written).
>    We have to take care of the disk-usage with this feature because
>    it may create a lot of dumps which are not removed yet.
In constants.h => CHPOX_MAX_DUMPS_PER_PID 5 => kill if new dump # is >
CHPOX_MAX_DUMPS_PER_PID.
Ok? :)

>
> 6) we have to think about how and when to remove process dumps
Check answer #5

>
> 7) we should add a check if the chpox module is available, if not
>    those register/unregister/checkpoint commands should be disabled
>    or display a notice that the user have to install chpox first.
>    This can be simply done by the gomd init script (insmoding chpox mod
>    and check if it returns ok) and then start the gomd with an additional
>    commandline parameter ....... just an idea.
np.

>
> If we have all this together the user can simple add checkpointing HA
> to his/her processes.
:)))

>
> .... as usual just Matt's mind  ;))
Great mind... ;)

Byez.

<rejected>