[katello-devel] Katello upgrade redesign

[Ivan Nečas]

On 10/26/2012 03:07 PM, Bryan Kearney wrote:
> On 10/26/2012 06:05 AM, Lukas Zapletal wrote:
>> Hello,
>>
>> working on https://bugzilla.redhat.com/show_bug.cgi?id=868916 , I 
>> found we
>> have some bugs and also design issues with katello upgrade.
>>
>> The current design is simple, we have two kinds of upgrade scripts which
>> are in two directories.
>>
>> /usr/share/katello/install/upgrade-scripts/default/*
>>
>> and
>>
>> /usr/share/katello/install/upgrade-scripts/upgrade/*
>>
>> Katello-upgrade first shuts downs all the services and then starts
>> upgrading by calling upgrade scripts in this order: default, upgrade.
>> Default scripts are executed every katello-upgrade call, while upgrade
>> scripts are only executed once (and then katello-upgrade "marks" them in
>> the /var/lib/katello/upgrade-history file (just a list of files which
>> have been already executed).
>>
>> Default scripts (executed every time) are:
>>
>> 0002_update_pulp.sh
>>   - starts mongod
>>   - does pulp-migrate
>> 0003_update_candlepin.sh
>>   - executes dpdb
>> 0004_migrate_katello_db.s
>>   - starts candlepin and elasticsearch
>>   - runs katello migration
>>
>> Upgrade scripts (executed only once) are:
>>
>> (none for CFSE 1.0/1.1 - just two examples that does nothing)
>>
>> 0001_preallocate_mongo.sh
>>   - prepares mongo journal for new version of mongo
>> 0002_create_foreman_user
>>   - creates foreman user
>>
>> Now there are couple of issues which are blockers for CFSE 1.1 and
>> couple of design issues I would like to also fix for Katello.
>>
>> Basically katello-upgrade currently does not work in CFSE 1.1 because we
>> have some code logic in the migration scripts (filters) which require
>> all the backend engines to be running. We are not starting pulp and also
>> elasticsearch starts slowly and we need to wait until it is available.
>>
>> Also there are couple of example migration scripts which does nothing,
>> but creating pyc/pyo bytecode files which are then added to the executed
>> list. I will remove them and make sure python scripts does not create
>> those.
>>
>> That is necessary for CFSE 1.1 upgrades, now for Katello we have a
>> design issue. Some scripts need the services to be running (like
>> pulp migration), others must not have services running (candlepin
>> migration).
>>
>> Therefore for Katello, I plan to split our upgrade scripts into two
>> categories (by script numbers):
>>
>> 0001-2999: Will be executed when backend engines are down
>> 3000-5999: Will be executed when backend engines are up
>> 6000-9999: Will be executed when backend engines and Katello are up
>>
>> This will be the same for both default and upgrade scripts. It would
>> look (default scripts) like:
>>
>> 0001_stop_all_services
>> 0010_migrate_candlepin
>> 3000_start_backend_engines
>> 3010_migrate_pulp
>> 3020_migrate_katello
>> 6000_start_katello
>
> I dont know if it matters.. but should we just do different 
> directories, instead of using magic numbers?
If what this should solve is order of scripts, I can't see how 
directories help solving it, since the order in the subdirs should be 
specified as well.

-- Ivan
>
> -- bk
>
>
>
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-- 
Ivan