We have updated the java minor version and Cassandra version as given below.
Older Java version "1.8.0_144" Newer Java version "1.8.0_261"
Older Cassandra version : 2.1.16 Newer Cassandra version : 3.11.2
Now we are getting below exception :
INFO [main] 2020-08-19 10:55:09,364 YamlConfigurationLoader.java:89 - Configuration
location: file:/etc/cassandra/default.conf/cassandra.yaml
Exception (org.apache.cassandra.exceptions.ConfigurationException) encountered during startup: Invalid yaml: file:/etc/cassandra/default.conf/cassandra.yaml
Error: null; Can't construct a java object for tag:yaml.org,2002:org.apache.cassandra.config.Config; exception=java.lang.reflect.InvocationTargetException; in 'reader', line 1, column 1:
cluster_name: VV Cluster
We did not change "cassandra.yaml". Same yaml is working on other nodes running on older versions.
Sometimes the issue is not with YAML. As suggested in this Datastax post, you can run a tool utlility like cassandra-stress which bypass the parser. This may help in identifying the real reason of failure.
Sometime it happens that YAML exception eats up the main issue and it appears as invalid yaml exception.