Healthcheck Service

Command Reference

healthcheck-configure

Usage: asadmin> healthcheck-configure --enabled=true|false --dynamic=true|false

Aim: Enables or disables the health check service. The command updates the domain.xml with the provided configuration but does not apply changes directly to the working service by default.

Command Options:

Option Type Description Default Mandatory
--target String The instance or cluster that will enable or disable its service server no
--dynamic Boolean Whether to apply the changes directly to the server without a reboot false no
--enabled Boolean Whether to enable or disable the service N/A yes

Example:

To enable the Healthcheck service such that it will only activate from the next time the server is restarted, the following command would be used:

asadmin> healthcheck-configure \
    --enabled=true \
    --dynamic=false

healthcheck-list-services

Usage: asadmin> healthcheck-list-services

Aim: Lists the names of all metric services that can be configured for monitoring.

Command Options

There are no options for this command.

Example

Running the command will show output similar to the example below:

Available Health Check Services:

healthcheck-cpool
healthcheck-cpu
healthcheck-gc
healthcheck-heap
healthcheck-threads
healthcheck-machinemem

healthcheck-configure-service

Usage: asadmin> healthcheck-configure-service --serviceName=<service.name> --name=<name> --enabled=true|false --dynamic=true|false --time=<integer.value> --unit=MICROSECONDS|MILLISECONDS|SECONDS|MINUTES|HOURS|DAYS

Aim: Enables or disables the monitoring of an specific metric. If enabling the service for an specific metric, the command also configures the frequency of monitoring for that metric. Command updates the domain.xml with provided configurations but does not apply changes directly to the working service by default. dynamic attribute should be set to true in order to apply the changes directly.

Command Options

Option Type Description Default Mandatory
--target String The instance or cluster that will enable or disable its metric configuration server no
--dynamic Boolean Whether to apply the changes directly to the server without a reboot false no
--enabled Boolean Whether to enable or disable the metric monitoring - yes
--serviceName String The metric service name. Must correspond to one of the values listed before - yes
--name String A user determined name for easy identification. This name is used in the service output, so any useful name can be chosen, though it should be unique among the services you have configured. One of:
CONP
CPUC
GBGC
HEAP
HOGT
MEMM		 no
--time Integer The amount of time units that the service will use to periodically monitor the metric 5 no
--unit TimeUnit The time unit to set the frequency of the metric monitoring. Must correspond to a valid java.util.concurrent.TimeUnit MINUTES no

If this command gets executed before running the healthcheck-configure command, the command will succeed and the configuration will be saved, but the healthcheck service will not be enabled.

Example

A very basic command to simply enable the GC checker and activate it without needing a restart would be as follows:

asadmin> healthcheck-configure-service --enabled=true --serviceName=healthcheck-gc --name=MYAPP-GC --dynamic=true

healthcheck-configure-service-threshold

Usage: asadmin> healthcheck-configure-service-threshold --serviceName=<service.name> --dynamic=true|false --thresholdCritical=90 --thresholdWarning=50 --thresholdGood=0

Aim: Configures CRITICAL, WARNING and GOOD threshold values for a service specified with its name. Command updates the domain.xml with provided configurations but does not apply changes directly to the working service by default. The dynamic attribute should be set to true in order to apply the changes directly.

This command only configures thresholds for the following metrics:

  • CPU Usage
  • JVM Heap Space
  • Host Memory
  • JDBC Connection Pools

Command Options

Option Type Description Default Mandatory
--target String The instance or cluster that will be configured server no
--dynamic Boolean Whether to apply the changes directly to the server without a reboot false no
--serviceName String The metric service name. Must correspond to one of the values listed before - yes
--thresholdCritical Integer The threshold value that this metric must surpass to log a CRITICAL event. A value between WARNING VALUE and 100 must be used 90 no
--thresholdWarning Integer The threshold value that this metric must surpass to log a WARNING event. A value between GOOD VALUE and CRITICAL VALUE must be used 50 no
--thresholdGood Integer The threshold value that this metric must surpass to log a GOOD event. A value between 0 and WARNING VALUE must be used 0 no

In order to execute this command for an specific metric, the healthcheck-configure-service command needs to be executed first.

Important!

There is no asadmin command to configure the Garbage Collection metric, since the service calculates and prints out how many times garbage collections were executed within the time elapsed since the last check. The service will determine the severity of the messages based on how much the CPU time is being taken by the GC when measuring.

Example

Monitoring the health of JDBC connection pools is a common need. In that scenario, it is very unlikely that on-the-fly configuration changes would be made, so a very high CRITICAL threshold can be set. Likewise, a nonzero GOOD threshold is needed because an empty or unused connection pool may not be healthy either. (The actual GOOD threshold would need to be arrived at following testing).

The following command would apply these settings to the connection pool checker:

asadmin> healthcheck-configure-service-threshold \
    --serviceName=healthcheck-cpool \
    --dynamic=true \
    --thresholdCritical=95 \
    --thresholdWarning=70 \
    --thresholdGood=30

healthcheck-hoggingthreads-configure

Usage: asadmin> healthcheck-hoggingthreads-configure --dynamic=true|false --threshold-percentage=50 --retry-count=3

Aim: Configures the healthcheck service to scan for threads hogging the CPU. The service will determine which threads fullfill this conditions by calculating a parcentage of usage with the ratio of elapsed time to the checker service execution interval. If this percentage exceeds the threshold-percentage, the thread will be marked as a hogging thread.

You can also use this command to enable this metric checking and also configure the frequency of monitoring combining the functions of the healthcheck-configure and healthcheck-configure-service commands.

Command Options

Option Type Description Default Mandatory
--target String The instance or cluster that will be configured server no
--enabled Boolean Whether to enable or disable the service true no
--dynamic Boolean Whether to apply the changes directly to the server without a reboot false no
--threshold-percentage Integer The threshold value that this metric will be compared to mark threads as hogging-threads 95 no
--retry-count Integer The number of retries that the checker service will execute in order to identify a hogging thread 3 no
--time Integer The periodic amount of time units the checker service will use to monitor hogging threads 1 no
--unit TimeUnit The time unit to set the frequency of the metric monitoring. Must correspond to a valid java.util.concurrent.TimeUnit SECONDS no

Example

Monitoring which threads hog the CPU is extremely important since this can lead to performance degradation, deadlocks and extreme bottlenecks issues that web applications can incur. In some cases the defaults are all that is needed, but imagine that in a critical system you want to set the threshold percentage to 90%, and you want to make sure that the healthcheck service guarantees the state of such threads with a retry count of 5. Additionally, you want to set the frequency of this check for every 20 seconds.

The following command would apply these settings to the connection pool checker:

asadmin> healthcheck-hoggingthreads-configure \
    --dynamic=true \
    --threshold-percentage=90 \
    --retry-count=5 \
    --time=20 \
    --unit=SECONDS

get-healthcheck-configuration

Usage: asadmin> get-healthcheck-configuration
 
Aim: Lists the current configuration for the health check service and for the configured metrics in a tabular format.

Command Options

There are no options for this command.

Example

A sample output is as follows:

Health Check Service Configuration is enabled?: true

Below are the list of configuration details of each checker listed by its name.

Name    Enabled    Time    Unit
GC      false      10      SECONDS

Name    Enabled    Time    Unit     Threshold Percentage    Retry Count
HT      true       10      SECONDS  95                      3

Name    Enabled    Time    Unit     Critical Threshold      Warning Threshold      Good Threshold
CONP    true       5       MINUTES  70                      40                     20
CPU     false      10      SECONDS  40                      20                     2
HP      false      8       SECONDS  -                       -                      -
MM      false      7       SECONDS  -                       -                      -

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