NameNode Health Tests

This is a NameNode health test that checks the NameNode's filesystem checkpoint is no older than some percentage of the Filesystem Checkpoint Period and that the number of transactions that have occurred since the last filesystem checkpoint does not exceed some percentage of the Filesystem Checkpoint Transaction Limit. A failure of this health test may indicate a problem with the active NameNode or its configured checkpointing role, i.e. either a standby NameNode or a SecondaryNameNode. Check the NameNode logs or the logs of the checkpointing role for more details. This test can be configured using the Filesystem Checkpoint Age Monitoring Thresholds and Filesystem Checkpoint Transactions Monitoring Thresholds NameNode monitoring setting.

Short Name: Checkpoint Status

This is a NameNode health test that checks whether the filesystems containing the data directories have sufficient free space. This test can be configured using the Data Directories Free Space Monitoring Absolute Thresholds and Data Directories Free Space Monitoring Percentage Thresholds NameNode monitoring settings.

Short Name: Data Directories Free Space

This NameNode health test checks that the number of file descriptors used does not rise above some percentage of the NameNode file descriptor limit. A failure of this health test may indicate a bug in either Hadoop or Cloudera Manager. Contact Cloudera support. This test can be configured using the File Descriptor Monitoring Thresholds NameNode monitoring setting.

Short Name: File Descriptors

This NameNode health test factors in the health of the host upon which the NameNode is running. A failure of this test means that the host running the NameNode is experiencing some problem. See that host's status page for more details.This test can be enabled or disabled using the NameNode Host Health Test NameNode monitoring setting.

Short Name: Host Health

This is a NameNode health test that checks that the NameNode is not out-of-sync with too many JournalNodes. This test is disabled if Quorum-based storage is not in use.A failure of this health test may indicate a problem with the JournalNodes or a communication problem between the NameNode and the JournalNodes. Check the NameNode and the JournalNode logs for more details.This test can be configured using the NameNode Out-Of-Sync JournalNodes Thresholds NameNode monitoring setting.

Short Name: JournalNode Sync Status

This NameNode health test checks that the filesystem containing the log directory of this NameNode has sufficient free space. This test can be configured using the Log Directory Free Space Monitoring Absolute Thresholds and Log Directory Free Space Monitoring Percentage Thresholds NameNode monitoring settings.

Short Name: Log Directory Free Space

This is a NameNode health test that checks for whether the NameNode has reported any failed data directories. A failure of this health test indicates that there is a problem with one or more data directories on the NameNode. See the NameNode system web UI for more information. Note that unless the configuration dfs.namenode.name.dir.restore is configured to true, the NameNode will require a restart to recognize data directories that have been restored (e.g., after an NFS outage). This test can be configured using the NameNode Directory Failures Thresholds NameNode monitoring setting.

Short Name: Name Directory Status

This NameNode health test checks that the NameNode threads are not experiencing long scheduling pauses. The test uses a pause monitoring thread in the NameNode that tracks scheduling delay by noting if it is run on its requested schedule. If the thread is not run on its requested schedule, the delay is noted and considered pause time. The health test checks that no more than some percentage of recent time is spent paused. A failure of this health test may indicate that the NameNode is not getting enough CPU resources, or that it is spending too much time doing garbage collection. Inspect the NameNode logs for any pause monitor output and check garbage collection metrics exposed by the NameNode. This test can be configured using the Pause Duration Thresholds and Pause Duration Monitoring Period NameNode monitoring settings.

Short Name: Pause Duration

This NameNode health test checks that the Cloudera Manager Agent on the NameNode host is heart beating correctly and that the process associated with the NameNode role is in the state expected by Cloudera Manager. A failure of this health test may indicate a problem with the NameNode process, a lack of connectivity to the Cloudera Manager Agent on the NameNode host, or a problem with the Cloudera Manager Agent. This test can fail either because the NameNode has crashed or because the NameNode will not start or stop in a timely fashion. Check the NameNode logs for more details. If the test fails because of problems communicating with the Cloudera Manager Agent on the NameNode host, check the status of the Cloudera Manager Agent by running /etc/init.d/cloudera-scm-agent status on the NameNode host, or look in the Cloudera Manager Agent logs on the NameNode host for more details. This test can be enabled or disabled using the NameNode Process Health Test NameNode monitoring setting.

Short Name: Process Status

This is a NameNode health test that checks that a moving average of the average time it takes for the NameNode to respond to requests does not exceed some value. A failure of this health test could indicate misconfiguration of the NameNode, that the NameNode is having a problem writing to one of its data directories, or may indicate a capacity planning problem. Check the NameNode's RpcQueueTime_avg_time and if this indicates that the bulk of the RPC latency is spent with requests queued, try increasing the NameNode Handler Count. If the NameNode's RpcProcessingTime_avg_time indicates the bulk of the RPC latency is due to request processing, check to see that each of the directories in which the HDFS metadata is being stored is performing adequately. This test can be configured using the NameNode RPC Latency Thresholds and NameNode RPC Latency Monitoring Window NameNode monitoring settings.

Short Name: RPC Latency

This is a NameNode health test that checks for the presence of an unfinalized HDFS rolling metadata upgrade. If an unfinalized HDFS rolling meatadata upgrade is detected, this test returns "Concerning" health. A failure of this health test indicates that a previously performed rolling metadata upgrade needs to be finalized. This can be done via HDFS Finalize Rolling Metadata Upgrade command. This test can be enabled or disabled using the HDFS Rolling Metadata Upgrade Status Health Test NameNode monitoring setting.

Short Name: Rolling Upgrade Status

This is a NameNode health test that checks that the NameNode is not in safemode. A failure of this health test indicates that the NameNode is in safemode. Look in the NameNode logs for more details. This test can be enabled or disabled using the NameNode Safemode Health Test NameNode monitoring setting. The Health Check Startup Tolerance NameNode monitoring setting also controls the amount of time at NameNode start up to tolerate safemode.

Short Name: Safe Mode Status

This NameNode health test checks that the NameNode has not recently exited unexpectedly. The test returns "Bad" health if the number of unexpected exits goes above a critical threshold. For example, if this test is configured with a critical threshold of 1, this test would return "Good" health if there have been no unexpected exits recently. If there has been 1 or more unexpected exits recently, this test would return "Bad" health. This test can be configured using the Unexpected Exits Thresholds and Unexpected Exits Monitoring Period NameNode monitoring settings.

Short Name: Unexpected Exits

This is a NameNode health test that checks for the presence of an unfinalized HDFS metadata upgrade. If an unfinalized HDFS metadata upgrade is detected, this test returns "Concerning" health. A failure of this health test indicates that a previously performed HDFS upgrade needs to be finalized. This can be done via the Finalize Metadata Upgrade NameNode command linked above. This test can be enabled or disabled using the HDFS Metadata Upgrade Status Health Test NameNode monitoring setting.

Short Name: Upgrade Status

This health test checks that the role's web server is responding quickly to requests by the Cloudera Manager Agent, and that the Cloudera Manager Agent can collect metrics from the web server. Failure of this health test may indicate a problem with the web server of the NameNode, a misconfiguration of the NameNode or a problem with the Cloudera Manager Agent. Consult the Cloudera Manager Agent logs and the logs of the NameNode for more detail. If the test's failure message indicates a communication problem, the Cloudera Manager Agent's HTTP requests to the NameNode's web server are failing or timing out. If the test's failure message indicates an unexpected response, the NameNode's web server responded to the Cloudera Manager Agent's request, but the response could not be interpreted for some reason. This test can be configured using the Web Metric Collection NameNode monitoring setting.

Short Name: Web Server Status