----- Original Message -----
From: "Dusmant Kumar Pati" <dpati@redhat.com> To: "Kanagaraj" <kmayilsa@redhat.com>, "engine-devel" <engine-devel@ovirt.org> Sent: Friday, November 29, 2013 1:40:09 PM Subject: Re: [Engine-devel] Using config values
On 11/29/2013 01:46 PM, Kanagaraj wrote:
Hi All,
The are some issues arising in configurations whenever we move up on the versions(3.3 => 3.4), because of the way we store and interpret them.
Whenever there is a new cluster level, you will need to add a new entry for all(most) of the configuration. Mostly a copy paste if you see from 3.2 to 3.3, except some CPU/PM type related configurations. Better option would be to have the defaul config value in ConfigValues.java and the overrides will go to config.sql. In this approach you don't need a new entries to config.sql when there is a new cluster level.
Lets take an exmaple, "SupportForceCreateVG" - This is supported from 3.1 onwards,
If you look at config.sql, you will see following entries select fn_db_add_config_value('SupportForceCreateVG','false','3.0'); select fn_db_add_config_value('SupportForceCreateVG','true','3.1'); select fn_db_add_config_value('SupportForceCreateVG','true','3.2'); select fn_db_add_config_value('SupportForceCreateVG','true','3.3');
And in ConfigValues.java
@TypeConverterAttribute(Boolean.class) @DefaultValueAttribute("false") SupportForceCreateVG,
Now if there is 3.4 and 3.5, the user needs to add 2 more entries, which i feel is redundant.
Instead we can make
@TypeConverterAttribute(Boolean.class) @DefaultValueAttribute("true") SupportForceCreateVG,
and have only the following in config.sql select fn_db_add_config_value('SupportForceCreateVG','false','3.0');
if a particular value(for a specific cluster level) is not found in Config.sql, the fallback is to use the value available in ConfigValues.java.
Please share your thoughts on this.
Hi First of all I think its a good idea I have 2 questions 1) Which value will be stored as default in the java class for configuration values that are not a boolean, that represents if a feature is active or not. Is that the latest version value ? sounds not obvious to me 2) There are some configuration values that are exposed to the user via the engine-config tool, how this will work, we can not remove the entries their since the user may change and override those values. I have a different suggestion: Default value will stay as is , meaning , it will reflect the value that should be used to keep the application running correctly if a value is not found in DB (which should not occur) Code of getting configuration value (getConfigValue(<key>,<version>) will be changed to get the closest version value to the given one. For example , if a 3.4 version is given for a given <key> and we have in DB just values for 3.0 and 3.1 , the 3.1 value is returned. I prefer this solution since it makes the config.sql file self documented , showing only value changes and in which version each change occurred. To implement that, we should add this mechanism to the current code that caches the DB content and as I see that it should be a simple change. engine-config should be modified such that if the user change a value, this value will be inserted to the database with the current release if not exists and then the mechanism described above will get this value Example: VdsFenceType lists all the supported fencing agents for power management , it currently has the following settings option_value | version ---------------------------------------------------------------------------------------------+--------- alom,apc,bladecenter,drac5,eps,ilo,ilo3,ipmilan,rsa,rsb,wti,cisco_ucs | 3.0 alom,apc,bladecenter,drac5,eps,ilo,ilo3,ipmilan,rsa,rsb,wti,cisco_ucs | 3.1 apc,apc_snmp,bladecenter,cisco_ucs,drac5,eps,ilo,ilo2,ilo3,ilo4,ipmilan,rsa,rsb,wti | 3.2 apc,apc_snmp,bladecenter,cisco_ucs,drac5,eps,ilo,ilo2,ilo3,ilo4,ipmilan,rsa,rsb,wti | 3.3 In the proposed solution, we will have option_value | version ---------------------------------------------------------------------------------------------+--------- alom,apc,bladecenter,drac5,eps,ilo,ilo3,ipmilan,rsa,rsb,wti,cisco_ucs | 3.0 apc,apc_snmp,bladecenter,cisco_ucs,drac5,eps,ilo,ilo2,ilo3,ilo4,ipmilan,rsa,rsb,wti | 3.2 This is clear and documents only the changes done between versions and serve all values: boolean , string and complex type (those which requires any kind of parsing) What do you think? Eli
Thanks, Kanagaraj
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel I think, this is a good suggestion...
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