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Papers on Analytical System Administration
- Computer Immunology
Proceedings of the Twelfth Systems Administration Conference
(LISA XII) (USENIX Association: Berkeley, CA), page 283, 1998
Present day computer systems are fragile and unreliable. Human
beings are involved in the care and repair of computer systems at
every stage in their operation. This level of human involvement will
be impossible to maintain in future. Biological and social systems of
comparable and greater complexity have self-healing processes which
are crucial to their survival. It will be necessary to mimic such
systems if our future computer systems are to prosper in a complex and
hostile environment. This paper describes strategies for future
research and summarizes concrete measures for the present, building
upon existing software systems.
- Measuring Host Normality
ACM Transactions on Computing Systems, 20, p-125-160 (2001)
A comparative analysis of transaction time-series is made, for light
to moderately loaded hosts, motivated by the problem of anomaly
detection in computers. Criteria for measuring the statistical state
of hosts are examined. Applying a scaling transformation to the
measured data, it is found that the distribution of fluctuations about
the mean is closely approximated by a steady-state, maximum-entropy
distribution, modulated by a periodic variation. The shape of the
distribution, under these conditions, depends on the dimensionless
ratio of the daily/weekly periodicity and the correlation length of
the data. These values are persistent or even invariant. We
investigate the limits of these conclusions, and how they
might be applied in anomaly detection.
- The kinematics of distributed computer transactions
International Journal of Modern Physics C12, p759-789 (2000)
A causal, stochastic model of networked computers, based on
information theory and non-equilibrium dynamical systems is
presented. This provides a simple explanatino for recent experimental
results revealing the structure of information in network
transactions. The model is based on non-Poissonian stochastic
variables, and pseudo-periodic functions. It explains the measured
patterns seen in resource variables on computers in network
communities. Weakly non-Poissonian behaviour can be eliminated by a
conformal scaling transformation, and leads to a mapping onto
statistical field theory. From this it is possible to calculate the
exact profile of the spectrum of fluctuations. This work has
applications to anomaly detection and time-series analysis of computer
transactions.
- Theoretical System Administration
Proceedings of the Fourteenth Systems Administration Conference
(LISA XIV) (USENIX Association: Berkeley, CA), page 1, 2000
In order to develop system administration strategies which can best
achieve organizations' goals, impartial methods of analysis need to be
applied, based on the best information available about needs and user
practices. This paper draws together several threads of earlier
research to propose an analytical method for evaluating system
administration policies, using statistical dynamics and the theory of
games.
- Scaling behaviour of peer configuration in logically ad hoc networks
IEEE eTransactions on Network and Service Management, p1 (2004)
Current interest in ad hoc and peer-to-peer networking
technologies prompts a re-examination of models for configuration
management, within these frameworks. In the future, network
management methods may have to scale to millions of nodes within a
single organization, with complex social constraints. In this paper,
we discuss whether it is possible to manage the configuration of large
numbers of network devices using well-known and not-so-well-known
configuration models, and we discuss how the special characteristics
of ad hoc and peer-to-peer networks are reflected in this problem.
- On the Theory of System Administration
Science of Computer Programming 49, p1 (2003)
This paper describes a mean field approach to defining and
implementing policy-based system administration. The concepts of
regulation and optimization are used to define the notion of
maintenance. These are then used to evaluate stable equilibria of
system configuration, that are associated with sustainable policies
for system management. Stable policies are thus associated with fixed
points of a mapping that describes the evolution of the system. In
general, such fixed points are the solutions of strategic games. A
consistent system policy is not sufficient to guarantee compliance;
the policy must also be implementable and maintainable. The paper
proposes two types of model to understand policy driven management of
Human-Computer systems: i) average dynamical descriptions of computer
system variables which provide a quantitative basis for decision, and
ii) competetive game theoretical descriptions that select optimal
courses of action by generalizing the notion of configuration
equilibria. It is shown how models can be formulated and simple examples
are given.
- Configurable immunity for evolving
human-computer systems
Science of Computer Programming 51 2004, p197-213
The immunity model, as used in the GNU cfengine project, is a
distributed framework for performing policy conformant system
administration, used on hundreds of thousands of Unix-like and Windows
systems. This paper describes the idealized approach to policy-guided
maintenance, that is approximated by cfengine, building on the notion
of `convergent' operations, i.e. those that reach stable equilibrium.
Agents gravitate towards a policy determined configurations, through
the repeated application of unintelligent `anti-body' operations or
discrete, coded countermeasures. The distributed agents turn passive
discovery of state into active strategy for `curing' systems of policy
transgressions. Keywords: autonomous computer management, cfengine,
immunity model.
- Autonomic Computing Approximated by Fixed-Point Promises
Proceedings of First IEEE International Workshop on Modelling Autonomic Communication Environments (MACE2006). p197-222
We use the concept of promises to develop a service oriented
abstraction of the primitive operations that make an autonomic
computer system. Convergent behaviour does not depend on centralized
control. We summarize necessary and sufficient conditions for
maintaining a convergently enforced policy without sacrificing
autonomy of decision, and we discuss whether the idea of versioning control
or ``rollback'' is compatible with an autonomic framework.
- A Risk Analysis of Disk Backup or Repository Maintenance
Science of Computer Programming (to appear 2006/7)
We discuss a simple model of disk backups and other
maintenance processes that include change to computer data. We
determine optimal strategies for scheduling such processes. A maximum
entropy model of random change provides a simple and intuitive guide
to the process of sector based disk change and leads to an easily
computable optimum time for backup that is robust to changes in the
model. We conclude with some theoretical considerations about
strategies for organizing backup information.
Modelling Next Generation Configuration Management Tools
Proceedings of the XX Large Installation System Administration Conference, LISA 2006. p131-147
There are several current theoretical models used to discuss
configuration management, including aspects, closures, and promises.
We examine how these models relate to one another, and develop a
overall theoretical framework within which to discuss configuration
management solutions. We apply this framework to classify the capabilities
of current tools, and develop requirements for the next generation of
configuration management tools.
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