decide the configuration policy in case of upgrade

[davidcoutadeur]

in case of package upgrade, what should be done for:

• slapd.conf (if existing)
• slapd.d (if existing)

Especially:

• do we provide an example of the new configuration? how?
• do we apply migration rules in slapd.conf automatically? (schema change, new configuration directive,...)
• do we apply migration rules in slapd.d automatically? (schema change, new configuration directive,...)

[davidcoutadeur]

action: check the community's opinion

[davidcoutadeur]

After discussing with the community:

The main things that have changed:

• many modifications in the configuration schema (cn=schema,cn=config)
  • some modifications in the additional schemas (core, cosine,...)
  • a few modifications in the database and overlay entries (for example, olcDbMaxEntrySize, olcPPolicyDisableWrite, objectClass: olcMemberOf -> objectClass: olcMemberOfConfig)

• the cn=schema,cn=config entry content is loaded dynamically in memory. The content delivered by a slapd.conf to cn=config conversion is useless.
• additional schemas modifications won't change a lot (because they are defined in RFCs). Some minor changes can happen, like a description change
• database and overlay entries won't change a lot, and if so the community will keep the old names as aliases

Considering this, there is no need for updating the configuration while upgrading openldap

We will provide slapd.conf and cn=config configurations, and cn=config will be the default deployed configuration, as discussed in #62