In the Hadoop cluster, I am running Spark 2.0 on a Client node, separately from Hive services.

If I would like to connect to Hive Metastore using spark-sql, hive-hcatalog-core-0.13.0.jar has to be added to the jars folder in Spark home directory.

Step into $SPARK_HOME/jars folder and run the following

sudo -u spark wget http://central.maven.org/maven2/org/apache/hive/hcatalog/hive-hcatalog-core/0.13.0/hive-hcatalog-core-0.13.0.jar

Now I can run spark-sql and queries on the tables in the databases.

If the jar file is missing, and by running for example

desc table_name

the following error message is displayed

ERROR hive.log: error in initSerDe: java.lang.ClassNotFoundException Class org.apache.hive.hcatalog.data.JsonSerDe not found
java.lang.ClassNotFoundException: Class org.apache.hive.hcatalog.data.JsonSerDe not found
        at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:2101)
        at org.apache.hadoop.hive.metastore.MetaStoreUtils.getDeserializer(MetaStoreUtils.java:385)
        at org.apache.hadoop.hive.ql.metadata.Table.getDeserializerFromMetaStore(Table.java:276)
        at org.apache.hadoop.hive.ql.metadata.Table.getDeserializer(Table.java:258)
        at org.apache.hadoop.hive.ql.metadata.Table.getCols(Table.java:605)
        at org.apache.spark.sql.hive.client.HiveClientImpl$$anonfun$getTableOption$1$$anonfun$apply$8.apply(HiveClientImpl.scala:339)
        at org.apache.spark.sql.hive.client.HiveClientImpl$$anonfun$getTableOption$1$$anonfun$apply$8.apply(HiveClientImpl.scala:335)
        at scala.Option.map(Option.scala:146)
        at org.apache.spark.sql.hive.client.HiveClientImpl$$anonfun$getTableOption$1.apply(HiveClientImpl.scala:335)
        at org.apache.spark.sql.hive.client.HiveClientImpl$$anonfun$getTableOption$1.apply(HiveClientImpl.scala:333)
        at org.apache.spark.sql.hive.client.HiveClientImpl$$anonfun$withHiveState$1.apply(HiveClientImpl.scala:262)
        at org.apache.spark.sql.hive.client.HiveClientImpl.liftedTree1$1(HiveClientImpl.scala:209)
        at org.apache.spark.sql.hive.client.HiveClientImpl.retryLocked(HiveClientImpl.scala:208)
        at org.apache.spark.sql.hive.client.HiveClientImpl.withHiveState(HiveClientImpl.scala:251)
        at org.apache.spark.sql.hive.client.HiveClientImpl.getTableOption(HiveClientImpl.scala:333)
        at org.apache.spark.sql.hive.HiveExternalCatalog$$anonfun$tableExists$1.apply$mcZ$sp(HiveExternalCatalog.scala:228)
        at org.apache.spark.sql.hive.HiveExternalCatalog$$anonfun$tableExists$1.apply(HiveExternalCatalog.scala:228)
        at org.apache.spark.sql.hive.HiveExternalCatalog$$anonfun$tableExists$1.apply(HiveExternalCatalog.scala:228)
        at org.apache.spark.sql.hive.HiveExternalCatalog.withClient(HiveExternalCatalog.scala:72)
        at org.apache.spark.sql.hive.HiveExternalCatalog.tableExists(HiveExternalCatalog.scala:227)
        at org.apache.spark.sql.catalyst.catalog.SessionCatalog.tableExists(SessionCatalog.scala:456)
        at org.apache.spark.sql.catalyst.catalog.SessionCatalog.requireTableExists(SessionCatalog.scala:126)
        at org.apache.spark.sql.catalyst.catalog.SessionCatalog.getTableMetadata(SessionCatalog.scala:274)
        at org.apache.spark.sql.execution.command.DescribeTableCommand.run(tables.scala:414)
        at org.apache.spark.sql.execution.command.ExecutedCommandExec.sideEffectResult$lzycompute(commands.scala:60)
        at org.apache.spark.sql.execution.command.ExecutedCommandExec.sideEffectResult(commands.scala:58)
        at org.apache.spark.sql.execution.command.ExecutedCommandExec.doExecute(commands.scala:74)
        at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$1.apply(SparkPlan.scala:115)
        at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$1.apply(SparkPlan.scala:115)
        at org.apache.spark.sql.execution.SparkPlan$$anonfun$executeQuery$1.apply(SparkPlan.scala:136)
        at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:151)
        at org.apache.spark.sql.execution.SparkPlan.executeQuery(SparkPlan.scala:133)
        at org.apache.spark.sql.execution.SparkPlan.execute(SparkPlan.scala:114)
        at org.apache.spark.sql.execution.QueryExecution.toRdd$lzycompute(QueryExecution.scala:86)
        at org.apache.spark.sql.execution.QueryExecution.toRdd(QueryExecution.scala:86)
        at org.apache.spark.sql.Dataset.<init>(Dataset.scala:186)
        at org.apache.spark.sql.Dataset.<init>(Dataset.scala:167)
        at org.apache.spark.sql.Dataset$.ofRows(Dataset.scala:65)
        at org.apache.spark.sql.SparkSession.sql(SparkSession.scala:582)
        at org.apache.spark.sql.SQLContext.sql(SQLContext.scala:682)
        at org.apache.spark.sql.hive.thriftserver.SparkSQLDriver.run(SparkSQLDriver.scala:62)
        at org.apache.spark.sql.hive.thriftserver.SparkSQLCLIDriver.processCmd(SparkSQLCLIDriver.scala:331)
        at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:376)
        at org.apache.spark.sql.hive.thriftserver.SparkSQLCLIDriver$.main(SparkSQLCLIDriver.scala:247)
        at org.apache.spark.sql.hive.thriftserver.SparkSQLCLIDriver.main(SparkSQLCLIDriver.scala)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:497)
        at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:729)
        at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:185)
        at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:210)
        at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:124)
        at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)

Since all my clusters have Hive services running on separate nodes than Spark services, I would not know if this is needed in cases when Hive services and Spark services are on the same node.