MyClusterAwareService.java

import com.day.cq.jcrclustersupport.ClusterAware;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Properties;
import org.apache.felix.scr.annotations.Property;
import org.apache.felix.scr.annotations.Service;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Component(immediate = true, metatype = true, label = "Periodic Job", description = "Does something on a schedule")
@Service
@Properties({
        @Property(name = "service.vendor", value = "CSG"),
        @Property(name = "service.description", value = "Does stuff periodically"),
        @Property(name = "scheduler.expression", value = "0 * * * * ?")
})
public class MyClusterAwareService implements Runnable, ClusterAware {
    private boolean isMaster;
    Logger log = LoggerFactory.getLogger(this.getClass());

    @Override
    public void bindRepository(String repositoryId, String clusterId, boolean isMaster) {
        log.info("A new repository has been bound:" + repositoryId + "; clusterid:" + clusterId);
        this.isMaster = isMaster;
    }
    @Override
    public void unbindRepository() {
        //do something useful here...
    }

    public void run() {
        if (isMaster) {
            log.info("I am the master and will do my task.");
           //Do your task here.
        } else {
            log.info("I am the slave and will not do anything.");
        }
    }
}