Starting with r151014, the ability to have linked-image zones is available. In OmniOS, we chose to make linked-images an option, available through the “lipkg” brand zone. The only difference between an ipkg zone (the normal zone type for OmniOS) and lipkg zones is the linking of images.
A linked-image zone either has the same, or a superset, of publishers as the global zone has.
Linked images link the packages in a zone to the global zone. If you update the global zone's packages, the linked-image zones get updated alongside it. This means going forward, an upgrade with linked image zones does not require detaching and reattaching the zone. You can update zones on a running system (at the cost of losing some log state during the time of the upgrade and the time of a reboot), or you can simply halt the zones, do the upgrade, and reboot with all linked-image zones automatically updated.
It has its own page, but in a nutshell, the linkage in linked-image zones weakens some, unless you are using the new-in-r151022 “-r” flag for pkg(1).
Normal OmniOS zones are “ipkg” branded. To change a zone's brand, you must detach it first, and then reattach it.
zoneadm -z <zonename> detach
zonecfg -z <zonename> set brand=lipkg
zoneadm -z <zonename> attach -u
Once the brand is changed, will have its IPS image linked to the global zone's image. When you update the global zone, will have its software updated as well. One potential side-effect of this is that the zone may get software more new than the zone's tenant (if you have tenants on your zone) can cope with. It's this side effect that kept us from just making linked-images the default on ipkg zones, and prompted us to create the lipkg brand.