Challenges of Self-Managing Systems: a System

Administrator’s PerspectiveDr. Alva L. Couch, Associate Professor

of Computer Science, Tufts University, Medford, MA USA

couch@cs.tufts.edu

Sysadmins and self-managing systems

• Self-managing systems: built from bottom up, system-centric– How to make systems more robust

• System administration: built from the top down, administrator (people) centric– How to empower people to do their jobs

Sysadmin Challenges for Self-managing Systems

• Personal liability: it is not the self-healing system that can lose its job

• Semantic distance and the problem of common referents: system administrators do not understand what self-healing systems do

• Expense of policy changes: small changes can incur large (political) costs

• Interference with auditing: can’t both “fix it” and “analyze it”

Desirable Forms of Self-Management

• Strong closures: “keep the box closed!”– “Half-open” is worse than “open”– We don’t want to debug “your” code (or

“tweak your knobs”!)

• Guarantees: “what can we expect?”– SLA for administrators– Controls concentrate on SLA parameters:

optimization/intrusiveness tradeoffs

“Like Hardware”

• No need to build system

• Automatic baselining and upgrades

• Directly modify only configuration

• Configuration concentrates on SLA

• Replacement if fails

• Remote diagnosis

Low-Hanging Fruit

• Closed, optimized network services– File sharing– Web services

• Don’t forget management aids – Distributed

• backup and recovery• email and spam control• firewalling and virus control

– Tiered (local/remote) filesystems– User authentication and authorization

The Near Future

• Commoditization of services: file service becomes like routing; a reliable closed box. Already almost true.

• Gradual commoditization of higher-level “policy-free” services, e.g., user privilege management.

• System administrator’s job becomes component engineering.

What Won’t Happen

• Peer-peer adoption without strong convergence and fault-tolerance guarantees (peer-peer is a “problem”, not a “solution”)

• Commoditization of administrator interface and business policies: “variant taxonomies of policy”

Standards

• Existing standards– Will aid developers; should not concern administrators– About how a tool should interact, not about how an administrator

should interact

• Standards that have helped sysadmins: – pop, imap, smtp, … – Sysadmin controls service; user controls choice of client/GUI

• Some potentially helpful standards– Semantics of SLA parameters for component solutions– Base (“policy-free?”) semantics for user bindings including

authentication and authorization.

Conclusions

• Build self-managing components.

• Provide an interface with strong semantics.

• Let sysadmins do the rest: – User interface– Translation from business policy to system

policy.