Syndication relationships

1. Overview
2. Web content libraries and syndication relationships
3. Access control when syndicating
4. Solving Reference Errors during Syndication

Overview

Web Content Manager Syndication replicates one or libraries from one server to another server, Syndicators can syndicate libraries to multiple subscribers. Subscribers can subscribe to libraries from multiple syndicators. Syndication methods include...

Method	Description	Syndicated	Not syndicated
Live items	Mostly used when syndicating to a staging or delivery server.	Published; Expired.	Draft items, projects and items in a project are not syndicated.
Live and projects	Gradually syndicate projects to a staging or delivery server rather than syndicating all the items in a project after they all achieve a published state.	Published; Expired; Projects; Draft items in a project	Draft items outside of projects are not syndicated.
All items	All item syndication is mostly used when syndicating between servers within an authoring environment.	Published; Expired; Projects; Draft items; Versions; Deleted items

When we switch from "all item" syndication to "live and projects" syndication or "live item" syndication, any drafts previously syndicated to the subscriber are not removed. If we move a draft item from a library using "all item" syndication, to a library using "live item" syndication, the draft item will also be moved on the subscriber because the action occurred on the library using "all item" syndication. This behavior allows for some draft items to be included in a subscriber library even though "live item" syndication is being used.
Cross-version syndication is supported between the following releases. Syndication from a newer release to an older release is not supported:

• WebSphere Portal version 7.0.0.2 with CF26 or higher.
• WebSphere Portal 8.0.0.1 with CF09 or higher.
• WebSphere Portal 8.5 or higher.

Web content libraries and syndication relationships

Items in the WCM authoring environment, including templates, components, content items, and so on, are stored in libraries. For example, a single authoring server that develops content for two delivery servers...

• HR intranet site providing information intended for internal employees
• HR external site providing material intended for customers and other non-employees.

To support this environment...

1. Create a library for each site.
2. Set syndication relationships between authoring server and the delivery servers

We could also use three libraries, where one library contains data common to both the intranet and Internet sites and the other two libraries contain site-specific content.

To syndicate multiple libraries from one server to another, we can choose to use one syndication relationship that includes all the libraries, or we can choose to use separate syndication relationships for each library, or a combination of both approaches. We can use a single syndication relationship for libraries that reference each other, as when one library contains design items like templates used by content in the other library. If the libraries are independent of one another, and we might want to suspend syndication of one library, but not the other, create separate syndication relationships for each library.

First-time syndication to an existing library is not supported. If we attempt to syndicate a library to a subscriber that already has a library with the same name, an error results.

Information about a Library is only syndicated the first time syndication occurs and not on subsequent updates and rebuilds. If a library is renamed or library user access is changed, this information is not syndicated to the Subscriber. If we change the name of a library or change user access to a library, manually make the same changes to any subscriber libraries if we want the same settings on all the syndicated libraries.

If content from one library (Library A) uses an item from another library (Library B), include both libraries in the syndicator to ensure that all items are syndicated successfully. If we only include Library A in the syndicator, any items in Library A that reference items in Library B are not syndicated, and syndication errors are generated.

If we add a new library to a syndicator after the initial syndication, you click Update to force the new library to be syndicated immediately.

Access control when syndicating

Although syndication can be used to keep data current between libraries on different servers, access control settings for the libraries are not included as part of syndication. Depending on how the environment is set up and what policies we have in place for library access, there are additional considerations for access control when using syndication.

User consistency

For user level access to remain consistent between the syndicator and subscriber, both servers must be configured to use the same user repository. If different user repositories are used, syndication will occur but there will be errors in the subscriber log indicating missing users. If access controls are determined by only using virtual users and groups, such as "All authenticated" and "Anonymous Users", then there is no need to use the same user repository on the syndicator and subscriber.

First time syndication on a new library

Because library access control settings are not syndicated, manually set access permissions on the subscriber's library when syndicating for the first time. If the library does not exist on the subscriber, it will be created during syndication. By default, no access control settings are specified on the new library, so set them manually before users can access content in the new library. The settings on the subscriber library do not have to match those on the syndicator library. This allows us to specify different levels of access for users and groups on the subscriber.

Solving Reference Errors during Syndication

When seeing errors during syndication of items between systems like the one below...

Caused by: com.ibm.icm.ci.data.CDMReferentialIntegrityException: RT0002E: Error while calling a function updateItems of PLS data manager

...the issue is often caused by missing references caused by doing manual changes on the subscriber.

To solve the issue and getting the environments back in sync, the syndication mirror mode can be leveraged. When syndicating with mirror mode every library on the subscriber will match the syndicator.

Syndication modes

Each syndication relationship can be configured with a different syndication mode. This determines how syndication is scheduled.

mode="modetype"

configured	This uses the mode that is configured in the WCM WCMConfigService service.
automatic	Syndication is scheduled automatically based on the configured syndication interval set on the syndicator.
manual	Syndication occurs only when requested using the administration portlet.

Manual syndication types

We can manually syndicate using the following methods:

• Update

  Syndicate items that are newer than the previous syndication. Items that are newer than the last syndication on the syndicator are sent to the subscriber. Items that are newer on the subscriber are not updated. Items that are created on the subscriber that do not exist on the syndicator are not removed from the subscriber.

• Rebuild

  This method syndicates all items that are newer on the syndicator. All items that are newer on the syndicator are sent to the subscriber. Items that are newer on the subscriber are not updated. Items that are created on the subscriber that do not exist on the syndicator are not removed from the subscriber.

Rebuild with mirror

If we select the mirror option, all items on the subscriber are reset to mirror the syndicator. All items that are newer on the syndicator are sent to the subscriber. Items that are newer on the subscriber are overwritten with the older version from the syndicator. Items that are created on the subscriber that do not exist on the syndicator are removed from the subscriber. Version history is not syndicated.

The Rebuild with mirror option can only be used when syndicating between servers that use CF07 or higher. The Rebuild with mirror option must not be used with two-way syndication. Rebuild with mirror option can be used only on a syndicator.

The Rebuild with mirror option will not automatically cascade through all subscribers downstream of the syndicator. We might need to repeat the Rebuild with mirror action on subscribers further down the syndication chain to synchronize all servers.

With CF09 or higher installed, the Rebuild with mirror option automatically cascades through all subscribers downstream of the syndicator that are configured with automatic syndication. Downstream automatic syndication is paused while the upstream mirror is running. Syndication can still be run manually downstream while automatic syndication is paused downstream.

Comparison between Rebuild and Rebuild With Mirror

The scenarios described in this table happen only within configured libraries of the syndication pair. Subscriber-only modifications to items outside of the configured libraries are not modified by Rebuild with mirror.

Action	Rebuild	Rebuild with Mirror
Update item on syndicator.	Update item on subscriber.	Update item on subscriber.
Update item on subscriber.	No action.	Revert item on subscriber.
Delete item on syndicator.	Delete item on subscriber.	Delete item on subscriber.
Delete item on subscriber.	Add item on subscriber.	Add item on subscriber.
Add item on syndicator.	Add item on subscriber.	Add item on subscriber.
Add item on subscriber.	No action.	Purge item on subscriber.
Update item on syndicator and then update item on subscriber.	No action (subscriber modification preserved).	Revert item to syndicator version.

Parent Syndication