Introduction to glite Middleware

Transcription

1 Introduction to glite Middleware Malik Ehsanullah BARC Mumbai 1

2 Introduction The Grid relies on advanced software, called middleware, which interfaces between resources and the applications glite 3.1 based on Scientific Linux 4 glite 3.2 based on Scientific Linux 5 2

3 What glite does? What glite does not do Somehow my application just run faster My application can run as long as it needs Users can access to any resource Users can rely of a huge amount of software, libraries What glite can do Provides sharing of resources (CPUs, Storage, Sensors ) Allows the creation of virtual organizations (People, Groups) Applications will run faster only if properly developed and best if thought for Grid environments (Trivial parallelization, MPIs) Provides access to computational/storage/other resources accordingly to defined: Policies and Access rights 3

4 glite Grid glite Grid System aims to: Integrate Virtualize Manage RESOURCEs and SERVICEs across different Vos The glite middleware is the set of software packages able to do this 4

5 glite evolution glite - Lightweight Middleware for Grid Computing LCG-1 LCG-2 glite-1 glite-2 glite-3 GTK2 Web services based GTK4 5

6 Grid Scenario Usage scenario Many users of different organizations geographically ditributed (Virtual Oranizations VOs) requesting high computational and storage capacities, collaborating each other Many computational resources (computing power and storage) belongs to different institutions but transparently accessible Italian institute of Particle Physics VO VO Garr-B University of Catania VO?? Italian CNR 6

7 The user joins to a VO Overview INTERNET 7

8 The user joins to a VO Each VO shares grid resources to other VOs accordingly to several policies. Overview INTERNET 8

9 The user joins to a VO Each VO shares grid resources to other Vos accordingly to several policies. The Grid middleware allow to use and share: Computing Elements (CE) Storage Element (SE) Overview INTERNET 9

10 Overview The users join to a VO Each VO shares grid resources to other Vos accordingly to several policies. The Grid middleware allow to use and share: Computing Elements (CE) Storage Element (SE) Plus Additional services to empower the capabilities of the Grid INTERNET 10

11 The users join to a VO Each VO shares grid resources to other Vos accordingly to several policies. The Grid middleware allow to use and share: Computing Elements (CE) Storage Element (SE) Plus Additional servicees to empower the capabilities of the Grid Overview INTERNET Result: COLLABORATION 11

12 glite Main components services UI: User Interface WMS: Workload management system LB: Logging and bookkeeping service VOMS: Virtual Organization Management service BDII: Information system CE: Computing element (LCG/gLite) WN: Worker nodes SE: Storage element LFC: File catalog MyProxy: User Credential Storage 12

13 Components The User Interface (UI) is the user entry point normally considered as the user workstation. It is normally considered as a WMS component. The Workload Management System (WMS) is a set of services having the responsibility to find the best available computing element where to submit user s job in a transparent fashion The Logging and bookkeeping service (LB), keep track of user job execution in terms of statuses: Ready, Scheduled, Waiting, Running, Done The Computing element (CE) is the computational resource, the entry point to a cluster or PCs handled by a job queue management system; in particular: TORQUE, PBS, LSF, CONDOR The Worker Nodes are the machines where jobs are really executed and managed by the CE queue management system 13

14 Components The Information System and Monitoring maintain data related to available grid resources and their health status. The Virtual Organization Management service (VOMS), is the way glite improves the management of authentication and authorization to the Grid resources. The VOMS allows to their own members to define different access rights to VO resources The Storage element (SE) and the File catalogue (LFC), allow to manage Grid files and offer a mechanism to locate them easily for users and jobs. 14

15 Job life cycle 15

16 Expanded JDL Job Workflow in glite UI JDL Input sandbox Output sandbox DataSets info LFC Catalog Resource Broker Author. &Authen. Logging & Job Submit Event Book-keeping Job Query Job Status Job Status Job Submission Service 16 RSL Computing Element Publish Storage Element

17 Expanded JDL Job Workflow in glite UI JDL Input sandbox Output sandbox DataSets info LFC Catalog Resource Broker Job Submit Event Job Query Job Status RSL Job Submission Service Publish Storage Element Job Status 17

18 glite services glite services can be grouped in 5 main high level set of services Grid Access Security Information system & Monitoring Job Workload Management System Data Management 18

19 glite Grid access Two possibilities: APIs or CLI Built on top of them there exist GridPortals and GUIs 19

20 glite Security ( PKI ) User authentication is based on X.509 Authorized Certification Authorities (CA) can generate user and service certificates who identify univocally people or Grid services in the whole Grid Each Grid service may support or not certificates coming from different CAs To reduce the vulnerabilities the identification of users in to the grid is done through the use of proxy certificates. Proxies are signed copies of the original user certificate, having a limited lifetime. The use of Proxy certificates allows the following: Delegation: Any grid service can operates on the user behalf making signed copies of the original proxy. (Single Sign On) ( VOMS Add additional info (Add VO specific information provided by Store a long term proxy on a secure server (MyProxy) Renewal (A Proxy close to the expiration time can be automatically ( renewed 20

21 glite Security: AutH/AhtZ Authentication The user receive a certificate from a CA (PKI third party) He connects to the UI via SSH He Creates the proxy (single sign on) All grid services will use this proxy to identify the user. Authorization The user has to subscribe to a VO (VOMS) The VO establishes the user rights In any Grid service it will be verified if the user belongs to the VO and assigns the proper access rights to the user A special configuration file named the gridmapfile, maintains the correspondency between grid users and resource users (unix pool accounts) 21

22 VOMS Virtual Organization Membership Service Manages many Virtual Organizations (VOs). Multiple user roles can be defined inside each VO Extends the X509 schema Extensions are Digitally Signed Service maintenance provided by a web front-end Support MyProxy (stored proxies) Allow the access rights by VO or by Role Each Grid site associates to each VO member or role Allows to implement fine grained security policies to grid resources 22

23 VOMS Authentication Request VOMS AC C=IT/O=INFN /L=CNAF /CN=Pinco Palla /CN=proxy VOMS AC Auth DB 23

24 Joining a Virtual Organisation Users (and machines) are identified by certificates. Steps User obtains certificate from Certification Authority User registers at the VO usually via a web form VO manager authorizes the user VO DB updated User information is replicated onto VO resources within 24 hours Replicating VOMS DB once a day Obtaining certificate: Annually Joining VO: Once CA VO manager VO Membership VO Membership Service Service VOMS database VOMS database User s identity in the Grid = Subject of certificate: /C=IN/O=DAE/OU=BARC/CN=mvineet 24 Grid sites

25 MyProxy MyProxy Stores a long term proxy certificates to allow the automatic proxy renewal mechanism Allow to execute jobs requesting a computation time larger that the normal proxy lifetime (normally 12 hrs) The WMS is the responsible for the proxy renewal Users should not use long lived proxy directly Allow the user to access grid resources without carrying out the public and private keys. Proxy Delegation 25

26 Information System and Monitoring Berkeley Database Information Index (BDII) The information hierarchically stored via tree modeling (The LDAP implementation of GLUE) GRIS Stores information at resource level Site BDII Stores information at site level BDII Stores information at VO level VO Level BDII (gilda) Site Level Other GIIS (gilda) GIIS INFN sez. CT GIIS Merida (gilda) Globus MDS Resource Level GRISes GRISes GRISes 26

27 Workload Management WMS set of middleware components responsible of distribution and management of jobs across Grid resources. Two core components of WMS WM: accepts and satisfy requests for job management. (Matchmaking) is the process of assigning the best available resource. Logging & Bookeeping : keeps track of job execution in term of events: (Submitted, Running, Done,...) 27

28 Computing Element Service that represents the computing resource that is responsible to manage the queue of jobs to execute The CE may be used by a Generic Client: an end-user interacting directly with the Computing Element, or by the Workload Manager, which submits a given job to an appropriate CE found by the matchmaking process. Two job submission models : PUSH (Eager Scheduling) PULL (jobs pushed to CE), (Lazy Scheduling) (jobs coming from WMS when CE has free slots) 28

29 Computing Element: Architecture A CE refer to a set of computational resources (cluster, computing farm, etc.): CE Aceptance (CEA): generic interface to cluster. Includes the functionality of a site Gatekeeper LRMS (batch system): Condor, OpenPBS, Torque/Maui, LSF The cluster itself: Worker Nodes (WNs) CE Monitor (CEMon): deals with notifications about CE status, requests jobs to WMS (pull mode) For job submission, CE is able to work in pull or in push mode 27

30 Storage Element SE Services are at least: Storage back-end (Drivers and Hardware) Storage Resource Manager (SRM) Interface (Interface to manage the specific storage solution: dpm, rfio, ) Transfer service (Protocols: GridFTP(gsiftp), glubus-url-copy, ) Native POSIX like file I/O API (GFAL) 30

31 LFC File Catalog LFN (Logical file name) GUID (Grid unique identifier) SimLinks SURL (Site URL) TURL (Transfer URL) 31

32 Grid Services and their interactions Grid Access User Interface Info system Security MyProxy (Normal, Long term) VOMS Job submission WMS Computing Element Worker Node Data management Catalogs Storage elements BDII 32

33 Questions 33