I am getting the below error when i execute the ./start-appserver.sh for tomcat. i have checked the custom.properties file and and tomcatResource.xml my data source name is same.
2024-04-04 10:38:20 WARNING [main] org.apache.catalina.core.NamingContextListener.addResource Failed to register in JMX: [javax.naming.NamingException: Unexpected exception resolving reference [Root exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failureThe last packet successfully received from the server was 882 milliseconds ago. The last packet sent successfully to the server was 864 milliseconds ago.]]2024-04-04 10:38:24 INFO [main] org.apache.catalina.core.ApplicationContext.log No Spring WebApplicationInitializer types detected on classpathThu Apr 04 10:38:29 GMT 2024 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.2024-04-04 10:38:29 SEVERE [wait-for-component] org.apache.tomcat.jdbc.pool.ConnectionPool.init Unable to create initial connections of pool. com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
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The error suggests a communication problem between Tomcat and MySQL. Check server status, network, configurations, SSL setup, driver compatibility, database health, and enable detailed logging for diagnosis.
If you get a SQLException: Connection refused or Connection timed out or a MySQL specific CommunicationsException: Communications link failure, then it means that the DB isn't reachable at all. This can have one or more of the following causes:
SQLException: Connection refused
Connection timed out
CommunicationsException: Communications link failure
You can also check the database drivers which you are using on Appian to connect the database.
docs.appian.com/.../System_Requirements.html
If the problem were related with drivers, the error would be different
Verify Connectivity: --->Check if the database server is running and accessible from your Appian server (try pinging the database server's IP address) and --->Ensure there's no firewall blocking connections on the database port (usually 3306).
Check Credentials:-->custom.properties: Make sure the database URL, username, and password are correct.-->tomcatResource.xml: Verify the data source name matches custom.properties.
Address SSL Warning:-->Review your MySQL configuration and client settings if SSL is required. You may need to provide a truststore.