MDS-2.1 and Futures Karl Czajkowski Information Sciences Institute University of Southern California

Talk Outline l Introduction –Problem, history, etc. l MDS-2 Architecture –Protocols –Features, services l MDS-2.1 Software –Technology map l Information Model –Additional background

Resource Discovery/Monitoring l Distributed users and resources l Variable resource status l Variable grouping and connectivity R R R R R R ? ? R R R R RR R RR ? ? R R R R R dispersed users VO-AVO-B partioned network

Basic Grid Acquisition Phases l Resource Discovery –“What resources are relevant?” –Bootstraps planner state l Resource Status Query –“How do resources compare (now)?” –Refines planner knowledge l Resource Control –“Did I acquire the resources?” –Not an information service task!

MDS History l MDS-1 (classic) –Centralized database –Globus and earlier –Did not scale l MDS-2 –Distributed services –MDS 2.0 in Globus –New MDS 2.1 development in alpha release

Base Features l Virtual Organizations (Vos) –Group together resources –Support community-specific “discovery” –Specialized “views” l Scalability –Many resources –Many Vos –Graceful degradation of service

Virtual Organizations l Collaborating individuals and institutions –Shared goals –Enable sharing of resources –Non-locality of participants l Dynamic in nature –VOs come and go –Resources joing and leave Vos –Resource change status and fail l Community-wide goals

Scalability l Large numbers –Many resources –Many users l Independence –Resources shouldn’t affect one another –Vos shouldn’t affect one another l Graceful degradation of service –“As much function as possible” –Tolerate partitions, prune failures

New MDS-2.1 Features l Security –GSI mutual-authentication –Fine-grained access control by GSI name l Performance –Better query speeds –Less stale information l Extensibility l Convenience

Service Hierarchy l Resource Description via Info. Protocol (GRIP) –Co-located with resource on network l Aggregate Directories (via GRIP or other) –Can be made hierarchical l Dynamic Registration via Reg. Protocol (GRRP) discovery (GRIP?) lookup (GRIP) registration (GRRP) VO-specific AggDirs standard ResDesc services RRRR AA?

Distributed Services l Service scales with Grid growth l Loose consistency model tolerates failures l Interoperability by protocols D D D D

Soft-state Registration l Periodic notification –Service/resource is available –Expected-frequency metadata l Automatic extension –Add new resources to directories –Invite resource to join new directory l Self-cleaning –Reduce occurrence of “dead” references

MDS-2 Implementation l Grid Resource Information Service (GRIS) –Provides resource description –Modular content gateway l Grid Index Information Service (GIIS) –Provides aggregate directory –Hierarchical groups of resources l Lightweight Dir. Access Protocol (LDAP) –Standard with many client implementations –Used for GRIP (and GRRP currently)

MDS-2.1 Development Activities l Incorporating external advances –New OpenLDAP 2.0.x code-base –Cyrus-SASL/GSI security integration –Leveraging new Globus packaging model l Improving internal components –Better query servicing –New configuration/policy support –Invitation (reverse registration)

MDS-2.1 External Software Stack l OpenLDAP 2.0.x (.11) –Implements LDAPv3 protocol –Client and server components l Cyrus-SASL –Generic security –We provide loadable SASL/GSI plugin l Globus GSI (repackaged) –Provides GSS-API interface to PKI –Loadable module works with SASL plugin

MDS 2.1 Security l PKI authentication l Static authorization –Class, attribute, object name rules l “Self” authorization –Semi-dynamic rule –Requires “owner” attribute on objects l Dynamic authorization –Directory-based group lists (or future CAS) –Per-object access rule attributes

MDS-2.1 Internal Software l Wrappers/tools –Simplify typical idioms l Modular GRIS providers –Probe/query resource status –Generates LDIF-format data l LDAP server “backend” modules –GRIS provider dispatch/caching –GIIS implementation(s)

MDS-2.1alpha GRIS Providers globus-software reports Globus packages grid-info-host reports host OS info grid-info-host-interfaces reports NICs grid-info-host-load reports host load grid-info-host-filesystem reports disks globus-gram-reporter reports jobs

GRIS Dispatch Tests l Concurrent dispatch for each provider: 1.Could search intersect provider? No, then stop. 2.Is provider cache stale? Yes, then refill. 3.Apply search filter to cache data. l Combine all providers’ results

MDS-2.1 GRIS Configuration dn: sw=Globus, hn=${GLOBUS_HOSTNAME}, ${GRID_INFO_ ORGANIZATION_DN} objectclass: GlobusTop objectclass: GlobusActiveObject objectclass: GlobusActiveSearch type: exec path: /opt/globus-mds/bin base: globus-version args: -ldif cachetime: timelimit: 10 sizelimit: 1 …

GRIS Configuration cont’d dn: hn=${GLOBUS_HOSTNAME},{GRID_INFO_ORGANIZ ATION_DN} objectclass: GlobusTop objectclass: GlobusActiveObject objectclass: GlobusActiveSearch type: exec path: /opt/globus-mds/libexec base: globus-gram-reporter args: -f /opt/globus-mds/etc/globus-gram-rep orter.conf -onetime cachetime: 30 timelimit: 10 sizelimit: 20 …

Hierarchical GIIS l Maintain set of remote services –Track incoming live registrations –GRIS or GIIS registrants l Cached proxy results (now), or –Same cache logic as GRIS –Refill cache with “chaining” queries l LDAPv3 referral results (planned) –Do not maintain any local info cache –Redirect clients to active registrants

Extensible GIIS Framework l Modular registration actions –Re-use registration protocol decoding –Specialize directory update –e.g. prefetch indexable data l Modular query actions –Re-use query protocol decoding –Specialize query handler algorithm –e.g. utilize precomputed indices

MDS-LDAP Data Model l Info named within service l Info tagged with content type name(s) l Values associated with typed attributes values types name objectclass: computer system: mips irix dn: hn=hostX objectclass: service dispatchtype: immediate dn: queue=default, hn=hostX url: gram://hostname/default objectclass: queue dn: perf=load5, hn=hostX objectclass: perf objectclass: loadaverage period: 10 load5: 3.2 dn: store=scratch, hn=hostX objectclass: storage objectclass: raidstore free: MB raidmode: stripe

MDS-LDAP Query Model l Search scoping –Search rooted in namespace –Search depth of “root,” “root’s children,” or “root’s subtree” l Search filter –Value or type comparison –Logical combinations of filters l Namespace represents concept space

Namespace Management l Info is named uniquely within a service l Append “source name” to disambiguate locally, or use URLs to refer to remote info host host: hn=R3 host: hn=R2 host: hn=R1 host: hn=R2 host: hn=R1 host: hn=R2, O=O2 host: hn=R1, O=O2 host: hn=R3, O=O1 O1O2R1 R2R1R3R2R1 host: hn=R2, O=O1 AggDir ResDesc host: hn=R1, O=O1

More Information l Questions? l HPDC-10 Paper (to appear August 2001) –“Grid Information Services for Distributed Resource Sharing” l MDS-2.1 Alpha Website – –Early access to development code