Host Health Tests

This is a host health test that checks that the filesystem containing the Cloudera Manager Agent's log directory has sufficient free space. This test can be configured using the Cloudera Manager Agent Log Directory Free Space Monitoring Absolute Thresholds and Cloudera Manager Agent Log Directory Free Space Monitoring Percentage Thresholds host monitoring settings.

Short Name: Agent Log Directory

This is a host health test that checks whether the filesystem containing the Cloudera Manager Agent's parcel directory has sufficient free space. This test can be configured using the Cloudera Manager Agent Parcel Directory Free Space Monitoring Absolute Thresholds and Cloudera Manager Agent Parcel Directory Free Space Monitoring Percentage Thresholds host monitoring settings.

Short Name: Agent Parcel Directory

This is a host health test that checks that the filesystem containing the Cloudera Manager Agent's process directory has sufficient free space. The process directory contains the configuration files for the processes which the Cloudera Manager Agent starts. This test can be configured using the Cloudera Manager Agent Process Directory Free Space Monitoring Absolute Thresholds and Cloudera Manager Agent Process Directory Free Space Monitoring Percentage Thresholds host monitoring settings.

Short Name: Agent Process Directory

This is a host health test that checks that the host's Cloudera Manager Agent is heart beating correctly and has the correct software version. A failure of this health test may indicate a lack of connectivity with the host's Cloudera Manager Agent, a problem with the Cloudera Manager Agent, or that the Cloudera Manager Agent or Host Monitor software is out of date. Check the status of the Cloudera Manager Agent by running /etc/init.d/cloudera-scm-agent status on the host, or look in the host's Cloudera Manager Agent logs for more details. If this test reports a software version mismatch between the Cloudera Manager Agent and the Host Monitor, check the version of each component by consulting the appropriate logs or the appropriate status web pages. This test can be enabled or disabled using the Host Process Health Test host configuration setting.

Short Name: Agent Status

This is a host health test that checks if the host's system clock appears to be out-of-sync with its NTP server. The test checks that the absolute value of the host's clock offset as reported by 'ntpdc -c loopinfo' command is not too large. If the command fails, or the host's NTP daemon is not running the test will return "Bad" health. If NTP is not in use on the host, this check should be disabled for the host using the configuration options mentioned below. Cloudera recommends using NTP for time synchronization of Hadoop clusters. A failure of this health test may indicate a problem with the host's NTP service or configuration. This test can be configured using the Host Clock Offset Thresholds host configuration setting.

Short Name: Clock Offset

This is a host health test that checks that the host's hostname and canonical name are consistent when checked from a Java process. A failure of this health test may indicate that the host's DNS configuration is not correct. Check the Cloudera Manager Agent log for the names that were detected by this test. The hostname and canonical name are considered to be consistent if the hostname or the hostname plus a domain name is the same as the canonical name. This health test uses domain names from the domain and search lines in /etc/resolv.conf. This health test does not consult /etc/nsswitch.conf and may give incorrect results if /etc/resolv.conf is not used by the host. There may be a delay of up to 5 minutes before this health test picks up changes to /etc/resolv.conf. This test can be configured using the Hostname and Canonical Name Health Check host configuration setting.

Short Name: DNS Resolution

This is a host health test that checks that the host's DNS resolution completes in a timely manner. The DNS resolution duration is calculated by measuring the time that a call to getLocalHost in a Java process takes on this host. Please note that DNS information may be cached on the host and this caching may affect the reported resolution duration. A failure of this health test may indicate that the host's DNS configuration is set incorrectly or the hosts's DNS server is responding slowly. This test can be configured using the Host DNS Resolution Duration Thresholds host configuration setting.

Short Name: DNS Resolution Duration

This is a host health test that checks for network frame errors across all network interfaces. A failure of this health test may indicate a problem with network hardware (e.g. switches) and can potentially cause other service or role-level performance problems. Check the host and network hardware logs for more details. This test can be configured using the Host Network Frame Error Percentage Thresholds, Host Network Frame Error Check Window, Host Network Frame Error Test Minimum Required Packets host configuration settings.

Short Name: Frame Errors

This is a host health test that checks for network interfaces that appear to be operating at less than full speed. A failure of this health test may indicate that network interface(s) may be configured incorrectly and may be causing performance problems. Use the ethtool command to check and configure the host's network interfaces to use the fastest available link speed and duplex mode. This test can be configured using the Host's Network Interfaces Slow Link Modes Thresholds, Network Interface Expected Link Speed and Network Interface Expected Duplex Mode host configuration settings.

Short Name: Network Interface Speed

This is a health test that checks that the host has not swapped out more than a certain number of pages over the last fifteen minutes. A failure of this health test may indicate misconfiguration of the host operating system, or too many processes running on the host. Try reducing vm.swappiness, or add more memory to the host. This test can be configured using the Host Memory Swapping Thresholds, Host Memory Swapping Check Window host configuration settings.

Short Name: Swapping