I have a functioning HDP cluster that seems to be working perfectly except for Hive and Oozie,
which will not start. The problems with these two cropped up at install time,
but I (chose to) ignore them at the time as I did not need / want to use them
immediately (all I needed at first were basic Hadoop things like HDFS, Sqoop
and Flume, Map-Reduce, and so forth) so I installed these and left the problems
for later. I am now revisiting these ‘components’ as I need to find (and
fix) whatever is going wrong. I have started with Hive, and worked my way up
the problem chain, starting with the Hive Metastore failing to start and
working backward. To cut a long story very short, the step in the chain that is
failing is the schema-tool initialization of the Hive meta-store database
schema, and here the underlying (root) cause seems to be a jdbc problem – it fails
to load the drivers for some reason (relevant pats of the error message are): /usr/hdp/current/hive-client/bin/schematool -initSchema -dbType mysql
Metastore
connection URL:jdbc:mysql://hdata2.edi.local/hive
Metastore
Connection Driver :com.mysql.jdbc.Driver
Metastore
connection User:hive
org.apache.hadoop.hive.metastore.HiveMetaException:
Failed to load driver
Underlying
cause: java.lang.ClassNotFoundException : com.mysql.jdbc.Driver
***
schemaTool failed ***
Other programs - like sqoop for example - can connect to this
MySQL database over jdbc, so I cannot figure out why the Hive schema-tool
cannot. The errors messages suggest that it does not find the jdbc jar file,
but the right symlink is in /usr/share/java and everybody else seems to find it
without problem. I have v5.1.28 of the Oracle mysql-connector-java jar file which
is the current version, so it’s not a problem with back-level files either. I have MySQL installed on the ‘master’ node of the cluster; Ambari
is happily using it, I can drive it from the CLI, can read and write data to it
with flume, etc. So I know that it is installed correctly and working, that I
can connect to it from all the nodes in my cluster, and that it also has a
(empty) database for Hive to use, has users created and permission grants in
place, etc. So, I cannot figure out what the underlying problem is, and
I could use suggestions as to possible causes/solutions. Does Hive (well, the
Hive schema tool) need to have jdbc somewhere special? Regards, and thanks in advance to all, Rick
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