Models@run.time 2007
Monitoring using Constraint Checking as part
of Model Based System Management
Nashville, October 2, 2007
Christian Hein, Tom Ritter, Michael Wagner
Fraunhofer FOKUS
System Monitoring using Constraint Checking
as part of Model Based System Management
Outline – Monitoring using Constraint Checking as part
of Model Based System Management
 Introduction
 Monitoring using Constraint Checking
 Application on CORBA Components
 Conclusion
System Monitoring using Constraint Checking
as part of Model Based System Management
Introduction
 system management is always difficult in particular for
 self-managing systems
 complex systems
 in many cases critical points are
- size, distribution or heterogeneity
 many stakeholders with different viewpoints and different interests
 technical viewpoint
- managing resources and technologies
 system viewpoint
- managing system organization and non-functional policies (including
security)
 operational (business) viewpoint
- managing operational capabilities in order to optimize business effects
 information basis is the same but needs to be presented differently
System Monitoring using Constraint Checking
as part of Model Based System Management
Introduction
 use of model-base engineering techniques, methods and tools also in
case of system management
 model-based system management
- MBSM is an approach in which the medium that interfaces
between the system manager and the system itself is a model
of the system. [ModelPlex Deliverable D5.1a]
 constraint checking is part of model-base verification technique
 can be understood as analysing models against expected properties
 constraint checking and system management to identify malfunction
System Monitoring using Constraint Checking
as part of Model Based System Management
Introduction
 example of properties which could be monitored
 homogenous distribution of components to different nodes
 is a component more used than other components
 security or safety aspects: definition of security or safety boundaries with
constraints e.g.:
- maximum number of interconnections
- maximum number of specific components
System Monitoring using Constraint Checking
as part of Model Based System Management
Introduction
 our idea: we use tools which are normally used for development also for
management activities
 use of same models and notation
Management stakeholder
development tools
Real-World system
Operational manager
System manager
Technical manager
System Monitoring using Constraint Checking
as part of Model Based System Management
Monitoring using Constraint Checking
Constraint Checker
Management stakeholder
Real-World System
constraint set
Operational manager
System manager
result
Adapter
input
models
provides
Technical manager
conformsTo
run time meta model
run time model
System Monitoring using Constraint Checking
as part of Model Based System Management
Monitoring using Constraint Checking
 constraints are represented as OCL constraints
 Traditional formal languages (e.g. Z) require good mathematical
understanding from users
- mostly applied in academic world, not in industry
- hard to learn, to complex in application
 The Object Constraint Language (OCL), provided by the OMG, has
been developed to achieve the following goals:
- formal, precise, unambiguous
- applicable for a large number of users (business or system
modeler, programmers)
- Specification language
- not a Programming language
 many tools already available
System Monitoring using Constraint Checking
as part of Model Based System Management
Content – Monitoring using Constraint Checking as part
of Model Based System Management
 Introduction
 Monitoring using Constraint Checking
 Application on CORBA Components
 Conclusion
System Monitoring using Constraint Checking
as part of Model Based System Management
Application on CORBA Components
 CORBA Component Model
 platform used for distributed
systems
 support of design, deployment
and execution
 support introspection
mechanism; a good candidate
to proof the concept
System Monitoring using Constraint Checking
as part of Model Based System Management
Application on CORBA Components
 example scenario
 a Plane can be
tracked by a radar
station
 a Radar has its area
of observation
 a SimulationServer
retrieves the position
of all planes
 a Display presents
information from all
radar stations
a
SimulationController
creates new Planes
at random as well as
new Radar instances
Radar
SimulationServer
Radar
Display
SimulationController
Planes
System Monitoring using Constraint Checking
as part of Model Based System Management
Application on CORBA Components
System Monitoring using Constraint Checking
as part of Model Based System Management
Application on CORBA Components
System Monitoring using Constraint Checking
as part of Model Based System Management
Application on CORBA Components
System Monitoring using Constraint Checking
as part of Model Based System Management
Application on CORBA Components
System Monitoring using Constraint Checking
as part of Model Based System Management
Application on CORBA Components
 maximum number of specific component
 e.g. Planes
context CCM inv: ComponentInstantiation.allInstances()->select
(c|c.type.absoluteName=`Simulation:PlaneSessionImpl`)>size()
 Problem: How to deal with potential inconsistency of a snapshot ?
System Monitoring using Constraint Checking
as part of Model Based System Management
Application on CORBA Components
 The number of planes running on one computing device shall not be
significantly different from the number of planes on other computing devices.
 difference is significant if the difference is greater than 3
context HomeInstantiation def: HelpSet: OrderedSet(Integer) =
HomeInstanstiation.allInstances()->Iterate(
i: HomeInstantiation ; sum: Sequence(Integer)=Sequence{} |
sum->append(i.comp.size())).asOrderedSet()
context HomeInstantiation def: Range: Integer = HelpSet.last()-
HelpSet.first()
context HomeDef inv: if (identifier='PlaneHome') then
homeImpl->forAll(h|h.instance->forAll(Range<4))
else true endif
System Monitoring using Constraint Checking
as part of Model Based System Management
Application on CORBA Components
25000
introspection mechanism
15000
get a snapshot
10000
5000
0
0
100
200
300
400
500
600
700
number of componentinstances
2500
2000
time in ms
time in ms
20000
constraint checker
1500
1 Constraint
10 Constraints
1000
500
0
0
200
400
600
800
1000
number of componentinstances
System Monitoring using Constraint Checking
as part of Model Based System Management
Conclusion
 Advantages
 use of the same tools and techniques of development process also for
management
 already existing tool and run time model
 Disadvantages
 performance
 getting a consistency formal representation of the system
 Further research topics
 adequate representation in development tools for management
stakeholder
 Model Repairing
 improve introspection mechanism
 constraint checking with fuzzy semantic
System Monitoring using Constraint Checking
as part of Model Based System Management
Thank you !!!
Any comments or questions?
System Monitoring using Constraint Checking
as part of Model Based System Management