basic grid registry configuration – there is not any backup data grid registry configuration where...
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ping (GR 2.0)
ping (GR 1.0)
search service (GR 2.0)
search service (GR 1.0)
number of nodes
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time
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synchronization of databases
synchronization of routing tables
User
node A1 node A2 node A12...
XML DB
XML DB
XML DB
User
node A1 node A2 node A12...
XML DB
XML DB
XML DB
node A1 node A2 node A12...
XML DB
XML DB
XML DB
node A
node ABnode AAcurrent provider
Mathematics: AlgebraMathematics:
Discrete Mathematics
Mathematics
echotim
eout
XML DB
XML DB
node AA
Mathematics: Algebra
User
XML DB
2
echo 3
7
45
6
1
node A
node ABnode AA
Mathematics: AlgebraMathematics:
Discrete Mathematics
Mathematics
echotim
eout
node AAcurrent provider
Mathematics: Algebra
Administrator
3
ech
o 3
41
2
node AAAnew node
Mathematics: Algebra: Linear Algebra
node A
node ABnode AAunupdated
Mathematics: AlgebraMathematics:
Discrete Mathematics
Mathematics
echoech
o 2
node AAcurrent provider
Mathematics: Algebra
echo 1
1
3
node AAA
Mathematics: Algebra: Linear Algebra
2
echo
echo
node A
node ABnode AA
Mathematics: AlgebraMathematics:
Discrete Mathematics
Mathematics
echoech
o
XML DB
XML DB
node AAbackup
Mathematics: Algebra
Administrator
XML DB
ech
o
Basic Grid Registry configuration – there is not any backup data
Grid Registry configuration where every domain has duplicated information
Mathematics
User
Graph Theory
Discrete Mathematics
Algebra
1
XML DB
2
9
3
8
7 4
6
5
10Find all services
solving TSP problem
Marian Bubak1,2, Cezary Górka1, Marek Kasztelnik1, Maciej Malawski1,2, Tomasz Gubała2
1Institute of Computer Science AGH, Mickiewicza 30, 30-059 Kraków, Poland2Academic Computer Centre CYFRONET, Nawojki 11, 30-950 Kraków, Poland
[email protected], [email protected], [email protected], [email protected], [email protected]
• Building applications using Web or Grid services has become increasingly popular
• A user connects services into the workflow to perform needed computation
• There has to be a registry storing information about Web or Grid services (Grid Registry)
• Need of a fault-tolerant version of the Grid Registry• For fault tolerance data stored in registry has to be
redundant• If data are duplicated, a synchronization mechanism
is needed
M. Bubak, T. Gubala, M. Kapałka, M. Malawski, K. Rycerz, Workflow composer and service registry for grid applications, Future Generation Computer Systems, vol. 21, no. 1, 2005, pp. 79-86.
• stores information about Web and Grid services (syntactic, semantic and human-readable description)
• distributed, scalable• Grid-enabled
• The system is composed of single nodes
• Initial registry configuration.
• User can ask registry about information from Mathematics, Mathematics : Algebra and Mathematics : Discrete Mathematics domains
• Information stored in domain Mathematics : Algebra is duplicated
• Echo messages are sent to ancestors by all the nodes. It provides knowledge about current registry configuration
• Using Echo mechanism the registry detects that the node AA from domain Mathematics : Algebra crashed
• Registry reacts to this information – changes in Local Routing Table
• Query is redirected to backup node (1 – 7)
• One of the nodes from domain Mathematics : Algebra is still unreachable
• Administrator still can modify registry configuration (1 - 4)
• All information stored in registry is available for the user
• When broken node is repaired, it synchronizes information with the most up to date node from domain (2)
• All changed entries in Local Routing Table are updated in repaired node (2)
• If necessary, new connections are established (3)
The test shows a comparison between response time depending on number of hops that message has to pass while reaching its destination in prototype and fault-tolerant version of the Grid Registry
Before Grid Registry reacts to unreachable nodes, user can send query. Then it can be redirected to broken node. In this case error message is generated and then user's query is redirected to backup node. This test presents such a situation. Response time depends on number of generated error messages
Grid Registry can modify its Local Routing Table, so query will not be redirected to broken nodes. Graph presents response time depending on number of broken nodes
When broken node becomes reachable, Local Routing Table and XML database have to be synchronized. Test shows synchronization time depending on number of items that have to be synchronized
Functionality solving this problem is available in new version of the Grid Registry
• Every node is a single point of failure this problem could be solved by adding data redundancy• Desynchronization of data• Overloaded nodes