[Engine-devel] Introducing virt / gluster flags at cluster level

[Yair Zaslavsky]

On 03/04/2012 12:20 PM, Moti Asayag wrote:
> On 03/01/2012 12:54 PM, Shireesh Anjal wrote:
>> Hi,
>>
>> In order to identify whether a cluster exposes Gluster / Virtualization
>> capabilities, we plan to introduce two boolean columns - virt_service
>> and gluster_service in the vds_groups table. As per immediate plans, it
>> is intended to support only one service per cluster, meaning only one of
>> these two values can be true.
> 
> Couldn't there be additional future services in the future ? In that
> case perhaps worth considering enum for services, to be stored in a
> single service column, its values are: virt, gluster,...) instead of
> extending the vds_group table consistently when introducing new services
> (under the assumption no mix of services is allowed).
+1 on enum idea.
Even if mixture of services is allowed, we can still use this enum.

> 
>>
>> We plan to make following changes as part of the patch:
>>
>> 1) Introduce an upgrade script for adding following columns to the table
>> "vds_groups"
>>     - virt_service - boolean - NOT_NULL - default value true
>>     - gluster_service - boolean - NOT_NULL - default value false
>>
>> => What is the naming convention for naming the upgrade script? Is it
>> <major-version>_<minor-version>_<running-sequence-with-step-10>_script_description.sql
>> ? By that logic, the name of our script will be something like
>> 03_01_0560_add_service_columns_to_vds_groups.sql
> 
> Correct. Make sure to verify script sequence uniqueness (under
> ovirt-engine/backend/manager/dbscripts/upgrade) before pushing, since
> there is no enforcement for that.
> 
>>
>> 2) Modify vds_groups_sp.sql to introduce these arguments / variables in
>> save and update methods
>>
>> 3) Modify the DAO interface and implementation to introduce these
>> arguments / variables in the save/update methods and VdsGroupRawMapper.
>>
>> 4) Modify the DAO JUnit test class to take care of these new fields, if
>> required.
> 
> As part of DAO unit-test you should add the new columns and possible
> data to
> ovirt-engine/backend/manager/modules/dal/src/test/resources/fixtures.xml
> 
>>
>> 5) Modify class VDSGroup to introduce the two new boolean variables
>> virtService and glusterService and modify the methods equals and
>> hashCode to use these.
>>
>> => One question here. Most of the attributes of class VDSGroup have
>> annotations like @XmlElement and @Column. I think these are related to
>> jaxb and JPA. Are these annotations really required? If yes, how are
>> they useful?
>>
> 
> @XmlElement annotations could be deleted from that file as a prior patch
> to the patch-set.
> 
> JPA annotations could be ignored as not fully supported nor maintained.
> 
>> 6) REST API : Default populate these variables (virtService = true,
>> glusterService = false) before invoking the BLL command
>> (AddVdsGroupCommand / UpdateVdsGroupCommand). This makes sure that the
>> existing API won't break. No change in api.xsd for now.
>>
>> 7) webadmin create cluster code: Default populate the new variables,
>> same as above. No change in UI screen for now.
>>
>> => Alternatively, the variable declaration on VDSGroup itself can
>> initialize these variables with default values, so that changes to UI /
>> REST API code (points 6 and 7) may not be required immediately. What do
>> you suggest?
>>
>> Inputs / comments / suggestions welcome.
>>
> 
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