Marathon tasks example

Marathon API Checks

Marathon is a cluster-aware init system for creating distributed, fault-tolerant applications on to of Apache Mesos.

It features a REST API that provides JSON formatted output.

One way of using the check_http_json script with this API is to verify that the number of tasks running for each application is within a particular threshold. An example is shown below.

Sample Command Definition

# Marathon Task Check #
define command {
   command_name    check_marathon_tasks
   command_line    $USER2$/check_http_json.rb -u 'http://marathon:8080/v2/apps/$ARG1$' -e app.tasksRunning -p app.instances,app.tasksRunning --status_level 404:2 -w '$ARG2$' -c '$ARG3$'
}

The --status_level 404:2 allows the check to return a critical condition if the application has been deleted from Marathon altogether. In this instance Marathon returns a 404 response for the API query.

The -p app.instances,app.tasksRunning allows these values to be included in the performance metrics sent by the check command.

Sample Service Definition

# Check that the correct number of tasks is running.
# Return a warning if it is not exactly 20
# Return a critical if it is less than 15 or more than 25
define service {
    name             myapp-tasks
    description      My Application Tasks
    hosts            marathon
    check_command    check_marathon_tasks!myapp!20:20!15:25
}