Transcript Adobe AEM Meet-up Presentation 03/13/2014 Vijay Donthi Detecting CQ/CRX Cluster Slave node or master node Using repository crx.cluster.master  Create Cluster Aware OSGI Service  Topology.

Adobe AEM Meet-up Presentation
03/13/2014
Vijay Donthi
Detecting CQ/CRX Cluster Slave
node or master node
Using repository crx.cluster.master
 Create Cluster Aware OSGI Service
 Topology API starting AEM 5.6.1

Why chose Topology

crx.cluster.master: the value could be
null if clustering is disabled-not much
information about the instance or
clusterrepository.getDescriptor("crx.cluster.master");

Cluster Aware OSGi Service: not
recommended in 5.6.1- uses
ClusterAware interface
Discovery API and Topology
Clustering- multiple instances sharing
one common repository
 discovery-api provides access to the
current topology, and any changes in the
topology.
 Interfaces to know topology events and
information.
 Topology browser - Sling instances and
cluster view

Topology View
Topology browser can be accessed at:
http://localhost:4502/system/console/top
ology
 The discovery API introduces support for
Cluster Leader within each cluster
 The leader can be used to deal with
work that must be executed in one
instance of the cluster

Change events
TOPOLOGY_CHANGING: discovery
service detects that an instance is no
longer responding or has newly joined or
new leader instance
 TOPOLOGY_CHANGED: once the change
is confirmed in the topology
 PROPERTIES_CHANGED:sent when the
one or many properties have changed in
an instance in the current topology
 https://gist.github.com/vdonthi/9533102

Configure Discover Service
/system/console/configMgr/org.apache.s
ling.discovery.impl.Config
 Status updated with HTTP heart beats
 The Discovery Service sends periodic
POST requests (heartbeats) to Topology
Connector services to establish and
maintain connections with the topology

References
http://sling.apache.org/documentation/b
undles/discovery-api-and-impl.html
 http://helpx.adobe.com/experiencemanager/kb/create-cluster-aware-osgiservice.html
 https://dev.day.com/docs/en/cq/current/j
avadoc/org/apache/sling/discovery/pack
age-summary.html
