1. Grid Coordination by Using the Grid Coordination Protocol
R. Harakaly, F. Bonnassieux, P. Primet
Presented by:
Laurent LEFEVRE
CNRS-UREC, Lyon, FRANCE
INRIA RESO, LIP (UMR CNRS, ENS, INRIA, UCB), Lyon, FRANCE

2. Outline Why do we need grid scheduling? Grid Coordination Protocol
Features
Architecture
Multiple ring support
Robustness
Security
One time token
User Interface
Implementation and Results
Network monitoring
Configuration coordination
Network Topology Discovery
Summary
17 January 2019
GAN 2004

3. Why do we need grid scheduling?
Centralized services:
VO servers
CRL distribution servers
Configuration servers
Distributed services
Network monitoring and discovery
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GAN 2004

4. Grid Coordination Protocol
Based on the Probes Coordination Protocol (PCP)
Generalized functions, not focused only to the network monitoring
Ring with token approach
Multiple ring support with inter-ring host locking for scalability
Used for:
Network monitoring synchronization
Coordination of the configuration updates
Scheduling of information distribution
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GAN 2004

5. Features Openness: Possibility to schedule any service needed
Flexibility/Customizability: Full and easy (re)configuration/parametrization of the service on the remote nodes.
Robustness/Reliability: Necessity to provide fully reliable service
Scalability: Possibility to schedule big number of members
Security: Distributed information and participating member nodes must be secure.
One time token: information distribution on demand
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GAN 2004

6. GCP Architecture Distributed architecture Scalability
No central information source
No single point of failure
Distributed token registration
Distributed functions
Scalability
Ring: logical group of services
Support of multiple rings
Possibility to build hierarchy of rings
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GAN 2004

7. Multi-ring support Required by need of:
Support of scalability by creation of the ring hierarchy
Scheduling of different services (e.g. CRL update, topogrid, Iperf, etc.)
Multiple independent rings: danger of possible collision
Critical for active network measurements
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GAN 2004

8. Inter-Ring Experiment Collision
Collision possibility:
In case of multiple independent rings sharing one or more hosts
Ring1 members {1, 2, 6, 7}
Ring2 members {3, 4, 5, 7}
Solution:
Inter-ring host locking
Two measurements on
the same host 2 3 1 7 4 ! 6 5
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GAN 2004

9. GCP host locking mechanism
Unable to lock destination
Source and destination host locking
Conflicting experiments are delayed due to lock on the host
BLOCKED 2 3 1 7 4 6 5
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10. GCP Robustness Distributed architecture
No single point of failure
In case of failure of one measurement host, GCP will bypass it without any impact on a service periodicity
In case of reliable service the failure report can be created for later successful finishing of the task
Protocols based on token passing face to problems connected with lost and/or duplicated token.
Timeout based token recovery mechanism
Token_ID and regenerating_host_ID based duplicate token elimination
17 January 2019
GAN 2004

11. GCP Security Three main security issues:
Host Security: Impossibility to start non-approved service on the host, or action which compromises the host security
Token Security: Integrity of the token cannot be modified on the way
User Authentication: Assign owner to the token and base any token manipulation and service on this information
17 January 2019
GAN 2004

12. One Time Token New feature Token passes once through all member nodes.
Used for:
Non-periodic/on demand/interactive services
On demand CRL update
Ad Hoc monitoring measurements
On demand/interactive active network monitoring probes
Plan: Add possibility to define an arbitrary number of passes.
17 January 2019
GAN 2004

13. User Interface
Set of utilities is provided for easy manipulation (creation, deletion, update, ..) of the rings and for an external GCP host (un)locking.
C and JAVA API for embedding of GCP client functionality (ring creation, modification, etc.) is prepared.
17 January 2019
GAN 2004

14. edg-gcpd-admin output
bin]$ ./edg-gcpd-admin -L grid-nm.ifae.es
GCP daemon version: 2.0.7
Reporting node:
Ring name: pinger, token id: 940, options = 0
Token status: NORMAL Token state: WAITING
Period 1800, Delay 60, Timeout 600
Command: edg-pinger
Last execution timestamp: Fri Apr 9 10:50:
Members:
...
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15. Implementation and results
Most of presented use cases are already deployed on the application testbed of the European DataGrid project.
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GAN 2004

16. Network monitoring
Scheduling of the set of distributed network monitoring sensors
Scalability problems solved by multilayer monitoring architecture
Inter-ring locking used for avoiding the concurrent measurements between two rings Fr
Backbone
ring Es It
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17. Experiment periodicity measurement
count
period
token regeneration
Periodicity [s] 5 10 15 20
118
120
122
124
126
128
130
100
200
300
400
500
600
700
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18. Network monitoring configuration
Network monitoring management cannot be completely distributed. It is always centralized in one (or several) network operation centers.
Monitoring nodes then downloads the configuration files from these centers.
GCP enables to create the easily maintainable and configurable upgrade scenarios
This approach is easily applicable for any service which publish the information on a central node like (CA CRL updates, VO servers, etc.)
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GAN 2004

19. Network Topology Discovery
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20. Summary
GCP is a generic coordination protocol for grid control and management services
Stability and usability were demonstrated on the use cases already implemented in the EDG DataGrid project
Download:
Questions:
17 January 2019
GAN 2004