IMPALA-10771: Add Tencent COS support

This patch adds support for COS(Cloud Object Storage). Using the
hadoop-cos, the implementation is similar to other remote FileSystems.

New flags for COS:
- num_cos_io_threads: Number of COS I/O threads. Defaults to be 16.

Follow-up:
- Support for caching COS file handles will be addressed in
   IMPALA-10772.
- test_concurrent_inserts and test_failing_inserts in
   test_acid_stress.py are skipped due to slow file listing on
   COS (IMPALA-10773).

Tests:
 - Upload hdfs test data to a COS bucket. Modify all locations in HMS
   DB to point to the COS bucket. Remove some hdfs caching params.
   Run CORE tests.

Change-Id: Idce135a7591d1b4c74425e365525be3086a39821
Reviewed-on: http://gerrit.cloudera.org:8080/17503
Reviewed-by: Joe McDonnell <joemcdonnell@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>

tests/custom_cluster/test_restart_services.py

@@ -35,7 +35,7 @@ from TCLIService import TCLIService
 from beeswaxd.BeeswaxService import QueryState
 from tests.beeswax.impala_beeswax import ImpalaBeeswaxException
 from tests.common.custom_cluster_test_suite import CustomClusterTestSuite
-from tests.common.skip import SkipIfNotHdfsMinicluster, SkipIfGCS
+from tests.common.skip import SkipIfNotHdfsMinicluster, SkipIfGCS, SkipIfCOS
 from tests.hs2.hs2_test_suite import HS2TestSuite, needs_session
 
 LOG = logging.getLogger(__name__)
@@ -361,6 +361,7 @@ class TestGracefulShutdown(CustomClusterTestSuite, HS2TestSuite):
     return 'functional-query'
 
   @SkipIfGCS.jira(reason="IMPALA-10562")
+  @SkipIfCOS.jira(reason="IMPALA-10562")
   @pytest.mark.execute_serially
   @CustomClusterTestSuite.with_args(
       impalad_args="--shutdown_grace_period_s={grace_period} \