Zookeeper distributed systems and services to build clusters

1488. What is a cluster?
What 1489.zookeeper that?
1490. Why zookeeper? What things do?
1491.zookeeper three roles leader, follower, observer effect?
1492.zookeeper leader election process
1493.zookeeper profile management principles?
1494. What is solr cluster? Why use solr cluster?
1495.solr cluster structure is like?
1496. [machine] on how to build a cluster solr?
1497. [machine] How solrj operating solr cluster?
1498. [machine] solrj call solr cluster, how to integrate with Spring?
1499. [machine] zookeeper cluster structures.
1500. [machine] using solr clusters to achieve the "Search" function.
1501. Use zookeeper implement distributed lock