[ClusterLabs Developers] Resurrecting OCF

[Jan Pokorný]

On 19/08/16 11:14 +0200, Jan Pokorný wrote:
> On 19/08/16 10:59 +0200, Jan Pokorný wrote:
>> So, having some more thoughts on this, here's the possible action
>> plan (just for heartbeat -> clusterlabs transition + deprecating
>> some agents, but clusterlabs-staging -> clusterlabs would be similar):
>> 
>> # (adapt and) move original heartbeat agents
>> 
>> 1. have a resource.d subdirectory "clusterlabs" and move (possibly under
>>    new names) agents that were a priori updated to reflect new revision
>>    of OCF there
>> 
>> 2. have a resource.d subdirectory ".deprecated" (for instance) and
>>    move the RAs that are going to be sunset over there (i.e.,
>>    original heartbeat agents = agents moved to clusterlabs + agents
>>    moved to .deprecated + agents that remained under heartbeat, pending
>>    to be moved under clusterlabs)
>> 
>> # preparation for backward compatibility
>> 
>> 3. have a file with old heartbeat name -> new clusterlabs name mapping
>>    for the agents from 0., i.e., hence physically changed the directory;
>>    the format can be as simple as CVS with "old name; [new name]" lines
>>    where omitted new name means that actual name hasn't changed
>>    (unlike proposed IPaddress2 -> IP)
>> 
>> 4. have an XSL template that will convert resource references per the
>>    translation file from 3. (this XSLT should be automatically
>>    generated based on that file) and a script that will call
>>    something like:
>>    cibadmin -Q | xsltproc <XSLT> - | cibadmin --replace --xml-pipe
>> 
>> 5. have a shell script "__cl_compat__" (for instance, name clearly
>>    distinguishable will become handy later on), that will:
>>    - figure which symlink it was called under ("$0") and figure out
>>      how it should behave based on file from 3.:
>>      . $0 found as old name with new name -> clusterlabs/<new name>
>>        will be called
>>      . $0 found as old name without new name -> clusterlabs/<old name>
>>        will be called
>>      . $0 not found as old name -> .deprecated/<old name> will be
>>        called if exists (otherwise fail early)
>>    - if "$HA_RSCTMP/$(basename $0)_compat" exists, just run:
>>      $0 "$@"; exit $?
>>      the purpose here is to avoid excessive spamming in the logs
>>    - touch "$HA_RSCTMP/$(basename $0)_compat"
>>    - emit a warning "Your configuration referes to the agent with
>>      an obsolete specification", followed with corresponding:
>>       . "please consider changing ocf:heartbeat:<old name> to
>>          ocf:clusterlabs:<new name>, you may use <script from 4.>
>> 	 to ease such transition"
>>       . "please consider changing ocf:heartbeat:<old name> to
>>          ocf:clusterlabs:<old name>, you may use <script from 4.>
>> 	 to ease such transition"
>>       . "please consider finding another alternative for
>>          ocf:heartbeat:<old name> as this agent is not actively
>> 	 maintained and will be dropped in the next major release;
>> 	 alternatively, if you volunteer to maintain it,
>> 	 please reach developers at clusterlabs.org mailing list"
> 
> (apparently missing)
> 
>    - $0 "$@"

(apparently should have been, also in the shortcut path above)

   - <figured out new path to be called> "$@"

>> # plugging it all together
>> 
>> 6. for agents moved from heartbeat in any of clusterlabs/.deprecated,
>>    (items 1. and 2.), provide respective symlinks from heartbeat
>>    pointing to __cl_compat__ script from 5.
>> 
>> Possibly recycle for clusterlabs-staging idea.
>> 
>> 
>> Now, for the higher level tools (crm, pcs), they should avoid listing
>> or suggesting agents that are symlinks to files matching wildcard
>> "__*__", and perhaps even actively suggest the alternative if this
>> such one is to be used -- this could be reached by making __compat__
>> script from 5. handle one new action (to be reflected in the OCF
>> revision as optional), say "new-alias" that would output what
>> to use instead (based on file from 3. it works with anyway).

-- 
Jan (Poki)
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