YARN Services API Examples

You can use the YARN Services API for situations such as creating a single-component service and performing various operations on the service.

Create a simple single-component service with most attribute values as defaults

POST URL – http://localhost:8088/app/v1/services

POST Request JSON


{
  "name": "hello-world",
  "version": "1",
  "components": [
    {
      "name": "hello",
      "number_of_containers": 1,
      "artifact": {
        "id": "nginx:latest",
        "type": "DOCKER"
      },
      "launch_command": "./start_nginx.sh",
      "resource": {
        "cpus": 1,
        "memory": "256"
      }
    }
  ]
}

GET Response JSON

GET URL – http://localhost:8088/app/v1/services/hello-world

Note that a lifetime value of -1 means unlimited lifetime.

{
    "name": "hello-world",
    "version": "1",
    "id": "application_1503963985568_0002",
    "lifetime": -1,
    "components": [
        {
            "name": "hello",
            "dependencies": [],
            "resource": {
                "cpus": 1,
                "memory": "256"
            },
            "configuration": {
                "properties": {},
                "env": {},
                "files": []
            },
            "quicklinks": [],
            "containers": [
                {
                    "id": "container_e03_1503963985568_0002_01_000001",
                    "ip": "10.22.8.143",
                    "hostname": "myhost.local",
                    "state": "READY",
                    "launch_time": 1504051512412,
                    "bare_host": "10.22.8.143",
                    "component_name": "hello-0"
                },
                {
                    "id": "container_e03_1503963985568_0002_01_000002",
                    "ip": "10.22.8.143",
                    "hostname": "myhost.local",
                    "state": "READY",
                    "launch_time": 1504051536450,
                    "bare_host": "10.22.8.143",
                    "component_name": "hello-1"
                }
            ],
            "launch_command": "./start_nginx.sh",
            "number_of_containers": 1,
            "run_privileged_container": false
        }
    ],
    "configuration": {
        "properties": {},
        "env": {},
        "files": []
    },
    "quicklinks": {}
}

Update the lifetime of a service
PUT URL – http://localhost:8088/app/v1/services/hello-world
PUT Request JSON
Note that irrespective of what the current lifetime value is, this update request will set the lifetime of the service to 3600 seconds (1 hour) from the time the request is submitted. Therefore, if a service has remaining lifetime of 5 minutes (for example) and would like to extend it to an hour, OR if an application has remaining lifetime of 5 hours (for example) and would like to reduce it down to one hour, then for both scenarios you would need to submit the following request.
```
{
  "lifetime": 3600
}
```
Stop a service
PUT URL – http://localhost:8088/app/v1/services/hello-world
PUT Request JSON
```
{
    "state": "STOPPED"
}
```
Start a service
PUT URL – http://localhost:8088/app/v1/services/hello-world
PUT Request JSON
```
{
    "state": "STARTED"
}
```
Increase or decrease the number of containers (instances) of a component of a service
PUT URL – http://localhost:8088/app/v1/services/hello-world/components/hello
PUT Request JSON
```
{
    "number_of_containers": 3
}
```
Destroy a service
DELETE URL – http://localhost:8088/app/v1/services/hello-world

Create a complicated service – HBase

POST URL - http://localhost:8088/app/v1/services/hbase-app-1


{
  "name": "hbase-app-1",
  "lifetime": "3600",
  "version": "2.0.0.3.0.0.0",
  "artifact": {
    "id": "hbase:2.0.0.3.0.0.0",
    "type": "DOCKER"
  },
  "configuration": {
    "env": {
      "HBASE_LOG_DIR": "<LOG_DIR>"
    },
    "files": [
      {
        "type": "TEMPLATE",
        "dest_file": "/etc/hadoop/conf/core-site.xml",
        "src_file": "core-site.xml"
      },
      {
        "type": "TEMPLATE",
        "dest_file": "/etc/hadoop/conf/hdfs-site.xml",
        "src_file": "hdfs-site.xml"
      },
      {
        "type": "XML",
        "dest_file": "/etc/hbase/conf/hbase-site.xml",
        "properties": {
          "hbase.cluster.distributed": "true",
          "hbase.zookeeper.quorum": "${CLUSTER_ZK_QUORUM}",
          "hbase.rootdir": "${SERVICE_HDFS_DIR}/hbase",
          "zookeeper.znode.parent": "${SERVICE_ZK_PATH}",
          "hbase.master.hostname": "hbasemaster-0.${SERVICE_NAME}.${USER}.${DOMAIN}",
          "hbase.master.info.port": "16010"
        }
      }
    ]
  },
  "components": [
    {
      "name": "hbasemaster",
      "number_of_containers": 1,
      "launch_command": "sleep 15; /usr/hdp/current/hbase-master/bin/hbase master start",
      "resource": {
        "cpus": 1,
        "memory": "2048"
      },
      "configuration": {
        "env": {
          "HBASE_MASTER_OPTS": "-Xmx2048m -Xms1024m"
        }
      }
    },
    {
      "name": "regionserver",
      "number_of_containers": 1,
      "launch_command": "sleep 15; /usr/hdp/current/hbase-regionserver/bin/hbase regionserver start",
      "dependencies": [
        "hbasemaster"
      ],
      "resource": {
        "cpus": 1,
        "memory": "2048"
      },
      "configuration": {
        "files": [
          {
            "type": "XML",
            "dest_file": "/etc/hbase/conf/hbase-site.xml",
            "properties": {
              "hbase.regionserver.hostname": "${COMPONENT_INSTANCE_NAME}.${SERVICE_NAME}.${USER}.${DOMAIN}"
            }
          }
        ],
        "env": {
          "HBASE_REGIONSERVER_OPTS": "-XX:CMSInitiatingOccupancyFraction=70 -Xmx2048m -Xms1024m"
        }
      }
    },
    {
      "name": "hbaseclient",
      "number_of_containers": 1,
      "launch_command": "sleep infinity",
      "resource": {
        "cpus": 1,
        "memory": "1024"
      }
    }
  ],
  "quicklinks": {
    "HBase Master Status UI": "http://hbasemaster-0.${SERVICE_NAME}.${USER}.${DOMAIN}:16010/master-status"
  }
}