1. DOT’98 Heidelberg 1 A. Hoffmann & M. Born Requirements for Advanced Distribution and Configuration Support GMD FOKUS Andreas Hoffmann & Marc Born Email: { a.hoffmann, born } @fokus.gmd.de

2. DOT’98 Heidelberg 2 A. Hoffmann & M. Born Problems concerning deployment of distributed applications Requirement for engineering language Requirement for platform extensions Conclusion Overview

3. DOT’98 Heidelberg 3 A. Hoffmann & M. Born Need for distribution and configuration information ODLSDL System Design Validation MSC UML Requ. Captering Design Implementation Analysis Java C++ Coding Execution Information for distribution and configuration needed

4. DOT’98 Heidelberg 4 A. Hoffmann & M. Born Partitioning of specification and implementation into parts ready for distribution What is the unit for partitioning and distribution? –Depends from used language! –SDL: system, block, process –C++: CORBA objects? –ODL: objects, groups The partitioning problem

5. DOT’98 Heidelberg 5 A. Hoffmann & M. Born Assignment of the entities resulting from the partitioning (server, clients) to entities of the target environment (nodes, capsules...) Configuration (setting of properties) The installation or initial configuration problem

6. DOT’98 Heidelberg 6 A. Hoffmann & M. Born Re-assignment of the entities resulting from the partitioning to entities of the target environment Caused by several reasons: –QoS (or other constraints) violation –Version control –Changes of the environment The re-configuration problem

7. DOT’98 Heidelberg 7 A. Hoffmann & M. Born Partitioning of specification/implementation Target environment description Assignment of engineering spec. parts to target environment Configuration of target environment and spec. parts Dynamic update of Deployed System The process of configuration and distribution

8. DOT’98 Heidelberg 8 A. Hoffmann & M. Born What is needed to support deployment of distributed applications ? Engineering Language Partioning Assignment Configuration Platform Extensions Dynamic re-configuration

9. DOT’98 Heidelberg 9 A. Hoffmann & M. Born ODP - background for engineering Language ODP => Framework for open distributed systems Viewpoint Model => Managing the complexity of concurrent systems Only concepts; no methodology or concrete language Several appropriate languages for Computational Viewpoint ODL=>System structure (on Type Level Only) SDL=>System structure and behaviour... Need for an Engineering Viewpoint language

10. DOT’98 Heidelberg 10 A. Hoffmann & M. Born Advantages of separation of computational and engineering model Computational model remains stable Computational model serves for several purposes => Validation & simulation, test case gen., performance analysis Several engineering-mappings for the same computational model possible

11. DOT’98 Heidelberg 11 A. Hoffmann & M. Born Concepts of Engineering Language Defines engineering issues of the system –Partitioning of the system –Properties like binding mechanisms for interfaces (binder, stub, protocoll) –Communication mechanisms Defines the target environment –Nodes, capsules, cluster –Ressources and properties Allows assignment of constraints –QoS –Performance Textual and graphical representation?

12. DOT’98 Heidelberg 12 A. Hoffmann & M. Born Mapping from Computational to Engineering Viewpoint (2) O1 O3 O4 O2 Node1 Node2 Engineering1 Node2 Node1 Node4 Engineering3 O1 O3 O4 O2 Node3 O2 O1 O3 O4 Node1 Node2 Engineering2 O1 O3 O4 O2 Computational Environment1 Environment2

13. DOT’98 Heidelberg 13 A. Hoffmann & M. Born Support for Constraints Static and dynamic constraints –Static:Evaluation before CO instantiation Compiling constraints Instantiation constraints –Dynamic:Evaluation after CO instantiation Runtime constraints Types of constraints –Ressource constraints (e.g. band width, memory) –Execution constraints (e.g. shutdown coordination) –QoS constraints (e.g. response time) Constraints for –Types of COs and Groups of COs –Instances of those types –Both combined => Instance constraints must be compliant to type constraints QoS ObjectiveSubjective PerformanceTimeCostUsability

14. DOT’98 Heidelberg 14 A. Hoffmann & M. Born Support for Constraints(2) Computational ModelO1 O3 O4 O2 Instance Level Engineering Model Configuration Assignment Constraints Node1 Node2 Environment Model Constraints T1 T3 T4 T2 Type Level Constraints

15. DOT’98 Heidelberg 15 A. Hoffmann & M. Born Environment description Model for soft-/hardware –Equipment, devices, OS, DPE (Distr.Proc. Env.) functions Concepts –ODP concepts: node, capsule, cluster,... –Ressources and ressource types (for execution, communication) –Representations of DPE functions –Technology aspects (for practical reasons) Purpose –Description of an existing target environment –Abstract deployment requirements for a service Kinds of environment model –Abstract (DPE transparency) –Concrete (To support a concrete DPE)

16. DOT’98 Heidelberg 16 A. Hoffmann & M. Born Environment Model (2) Computational Model Abstract Environment Model Assignment (Abstract configuration) Assignment (Concrete configuation) Concrete Environment Model Concrete Environment Model Mapping Compliance Concrete DPE

17. DOT’98 Heidelberg 17 A. Hoffmann & M. Born Required platform extensions Monitoring of properties and analysis Evaluation of constraints (QoS, Performance...) Advanced management functions Cloning Replication Migration Version control

18. DOT’98 Heidelberg 18 A. Hoffmann & M. Born Conclusions Problems are: –Partitioning –Initial configuration (installation) –Dynamic re-configuration Possible solutions are: –Development of engineering language –Enhancement of execution platforms Starting points for development are: –ODP as theoretical background –UML and other notations for language development –Existing distributed processing environments (P715, GMD...)