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An Introduction to Apache Zookeeper, what is it used for ? How does it work and what is it's architecture ?
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Apache Zookeeper • What is it ? • How does it work ? • Problems • Architecture • Reliability www.semtech-solutions.co.nz info@semtech-solutions.co.nz
Zookeeper – What is it ? • A coordination service • For distributed systems • Makes cluster coordination • Fast • Scalable • Runs on a cluster of servers • Offers pre defined functionality • No need to “re invent the wheel” • Best for read dominant work loads www.semtech-solutions.co.nz info@semtech-solutions.co.nz
Zookeeper – How does it work ? • Works via an ensemble of servers • Clients write changes to ensemble • Changes processed strictly in order received • Ensemble selects a leader • Leader re elected in case of failure • Designed for small data volumes / meta data www.semtech-solutions.co.nz info@semtech-solutions.co.nz
Zookeeper – How does it work ? • Change considered successful if • It reaches a quorum • Quorum is at least half of ensemble • A server will disconnect clients if • It cant contact quorum within a given time • Cluster will function if half of servers up • When a failed server re starts it will • Re sync with the ensemble www.semtech-solutions.co.nz info@semtech-solutions.co.nz
Distributed System Problems What type of problems do distributed systems encounter • Inconsistency • Configuration inconsistencies across cluster • Race conditions • Unexpected behaviour due to timing of events • Dead locks • Contention for resources www.semtech-solutions.co.nz info@semtech-solutions.co.nz
Zookeeper – Name Space • Zookeeper nodes use a hierarchical name space • Like a file system but for low data volumes • Path elements separated by a slash ( “/” ) • Every node in name space identified by a path www.semtech-solutions.co.nz info@semtech-solutions.co.nz
Contact Us • Feel free to contact us at • www.semtech-solutions.co.nz • info@semtech-solutions.co.nz • We offer IT project consultancy • We are happy to hear about your problems • You can just pay for those hours that you need • To solve your problems