...

The architecture includes to consider two layers different aspects of clustering:

• The Operational Layer covers installation of Cluster Agents that is no different from installation of Standalone Agents. In addition it covers registration of Agents as members of an Agent clusterCluster.
• The Functional Layer is situated on top of the Operational Layer and defines a number of logical Agent clustersClusters.

Operational Layer

The architecture includes the clustering of Agents in the role of Director Agents for restart capabilities and the clustering of Agents acting as Subagents for high availability and scalability.

...

• Any number of Subagents can be selected to be part of a Subagent Cluster.
• The selection includes to specify the Scheduling Mode being one of fixed-priority or round-robin:
  • fixed-priority: execute jobs with the first Subagent and switch to the next Subagent only if the first Subagent becomes unavailable (active-passive cluster).
  • round-robin: execute each next job on the next Subagent (active-active cluster).

...

For Cluster Agents the following excerpt from the above list is used:

• In a first position a the Primary Director Agent is available. Optionally a second Secondary Director Agent can be available.
• Below the Director Agent entry the list of Subagents is displayed.
  
  

Add Agent Cluster

The Agent Cluster is situated in the operational layer and includes specification of Director Agents and Subagents.

...

• The next Subagent can be dropped to the area above the existing Subagent to specify its role as the first Subagent used with the fixed-priority scheduling mode.
  • In this mode the first Subagent is used and only if it becomes unavailable then the next Subagent will be used.
• The next Subagent can be dropped to the area below the existing Subagent to specify its roles as the next Subagent used with the fixed-priority scheduling mode.
  • In this mode the next Subagent is used only if the first Subagent becomes unavailable.
• The next Subagent can be dropped to the area right to the existing Subagent to specify use of the round-robin scheduling mode.
  • In this mode each next task is executed with the next Subagent.

If the next Subagent is added dropped to the area below the existing Subagent then a cluster with fixed-priority scheduling mode is created:

...

If the next Subagent is dropped to the area right to the existing Subagent then a cluster with round-robin scheduling mode is created:

Organize Subagent Clusters

Users have a number of options to organize their Subagent Clusters:

• For each Subagent JOC Cockpit automatically adds a cluster that holds the single Subagent.
  • This allows to assign an individual Subagent to a job should the job be executed with this Subagent only.
  • This Subagent Cluster is not visible and cannot be modified by users.
  • The name of the Subagent Cluster corresponds to the Subagent ID.
• Any number of Subagents can

...

• be added to a cluster.
  • Adding more Subagents to a round-robin cluster allows unlimited horizonal scaling.
  • Some might consider it paranoid to add a larger number of Subagents to a

...

• • fixed-priority cluster, however, users are free to create a chain of Subagents that can replace each other.
• Subagents can be added for both fixed-priority and round-robin scheduling

...

• modes within the same cluster.

Users can apply different strategies to manage operational Agent Clusters and functional Subagent Clusters.

• A single or a few Agent Clusters can be used that each holds a larger number of Subagent Clusters.
  • Each Subagent Cluster selects a number of Subagents.
  • The same Subagents can occur in any number of Subagent Clusters.
  • The same Subagents cannot occur in more than one Agent Cluster.
  • This scenario can be applied for load sharing between server nodes that act for a number of clustered applications.
• A larger number of Agent Clusters can be used that hold a single or a small number of Subagent Clusters.
  • Agent Clusters are autonomous and are not related to each other. 
  • Each Agent Cluster is assigned an individual Director Agent that is optionally clustered.
  • This scenario is preferably applied in a situation when communication between a Director Agent and Subagents should be limited to a few servers, for example for use of Agent Clusters in separate network zones.

Assign Subagent Cluster to Jobs

Each Subagent Cluster is individually assigned to a job.