https://community.cloudera.com/t5/Support-Questions/Database-is-not-connecting-when-trying-to-install-oozie/m-p/243250#M205048 <PRE>2019-06-27 03:39:42,688 - Check db_connection_check was unsuccessful. Exit code: 1. Message: ERROR: Unable to connect to the DB. Please check DB connection properties. com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. Traceback (most recent call last): File "/var/lib/ambari-agent/cache/custom_actions/scripts/check_host.py", line 546, in &lt;module&gt; CheckHost().execute() File "/usr/lib/ambari-agent/lib/resource_management/libraries/script/script.py", line 375, in execute method(env) File "/var/lib/ambari-agent/cache/custom_actions/scripts/check_host.py", line 207, in actionexecute raise Fail(error_message) resource_management.core.exceptions.Fail: Check db_connection_check was unsuccessful. Exit code: 1. Message: ERROR: Unable to connect to the DB. Please check DB connection properties. com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server</PRE> Thu, 27 Jun 2019 12:20:32 GMT vinith_alampall 2019-06-27T12:20:32Z https://community.cloudera.com/t5/Support-Questions/Database-is-not-connecting-when-trying-to-install-oozie/m-p/243250#M205048 <PRE>2019-06-27 03:39:42,688 - Check db_connection_check was unsuccessful. Exit code: 1. Message: ERROR: Unable to connect to the DB. Please check DB connection properties. com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. Traceback (most recent call last): File "/var/lib/ambari-agent/cache/custom_actions/scripts/check_host.py", line 546, in &lt;module&gt; CheckHost().execute() File "/usr/lib/ambari-agent/lib/resource_management/libraries/script/script.py", line 375, in execute method(env) File "/var/lib/ambari-agent/cache/custom_actions/scripts/check_host.py", line 207, in actionexecute raise Fail(error_message) resource_management.core.exceptions.Fail: Check db_connection_check was unsuccessful. Exit code: 1. Message: ERROR: Unable to connect to the DB. Please check DB connection properties. com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server</PRE> Thu, 27 Jun 2019 12:20:32 GMT https://community.cloudera.com/t5/Support-Questions/Database-is-not-connecting-when-trying-to-install-oozie/m-p/243250#M205048 vinith_alampall 2019-06-27T12:20:32Z https://community.cloudera.com/t5/Support-Questions/Database-is-not-connecting-when-trying-to-install-oozie/m-p/243251#M205049 <P><A rel="user" href="https://community.cloudera.com/users/114687/vinithalampally.html">@Alampally Vinith</A><BR /><BR />The error indicates that your MySQL Server seems may not be running healthy. The MYSQl server is not responding to the jdbc call of the driver. </P><PRE>Please check DB connection properties. com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure&nbsp; The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server</PRE><P>.</P><P>Please try to restart your MySQL Server and then verify the mysql connectivity from oozie host.</P><P><BR /></P><P>.</P> Thu, 27 Jun 2019 12:44:15 GMT https://community.cloudera.com/t5/Support-Questions/Database-is-not-connecting-when-trying-to-install-oozie/m-p/243251#M205049 jsensharma 2019-06-27T12:44:15Z