When the DA or DC is started, it fails to synchronise and come online and instead throws an error similar to the following in the log file - <HOME_IMDataAggregator>/apache-karaf-2.4.3/data/karaf.out;
Unable to update instance pid: Unable to find root instance in /opt/CA/IMDataAggregator/apache-karaf-2.4.3/instances/instance.properties
DX NetOps CAPM 20.2 and later
This error indicates that the configuration that the DA is trying to start with conflicts with configuration of a previous running instance that was not cleared properly when it was shutdown.
First shutdown any running instances of the DA and the ActiveMQ;
service dadaemon stop
service activemq stop
Then, delete the DA data sub-directory under the apache-karaf directory:
rm -rf /opt/CA/IMDataAggregator/apache-karaf-2.4.3/data
Then restart the dadaemon. Activemq will automatically get started when dadaemon starts
NOTE: Use the rm -r command with caution as this will recursively delete all directories specified and their contents.