YARN Service API

Bringing a new service on YARN today is not a simple experience. The APIs of existing frameworks are either too low level (native YARN), require writing new code (for frameworks with programmatic APIs) or writing a complex spec (for declarative frameworks).

This simplified REST API can be used to create and manage the lifecycle of YARN services. In most cases, the application owner will not be forced to make any changes to their applications. This is primarily true if the application is packaged with containerization technologies like Docker.

This document describes the API specifications (aka. YarnFile) for deploying/managing containerized services on YARN. The same JSON spec can be used for both REST API and CLI to manage the services.

Version information

Version: 1.0.0

License information

License: Apache 2.0 License URL: http://www.apache.org/licenses/LICENSE-2.0.html

URI scheme

Host: host.mycompany.com

Port: 8088(default RM port)

Schemes: HTTP

Consumes

application/json

Produces

application/json

Paths

Create a service

POST /app/v1/services

Description

Create a service. The request JSON is a service object with details required for creation. If the request is successful it returns 202 Accepted. A success of this API only confirms success in submission of the service creation request. There is no guarantee that the service will actually reach a RUNNING state. Resource availability and several other factors determines if the service will be deployed in the cluster. It is expected that clients would subsequently call the GET API to get details of the service and determine its state.

Parameters

Type	Name	Description	Required	Schema	Default
BodyParameter	Service	Service request object	true	Service

Responses

HTTP Code	Description	Schema
202	The request to create a service is accepted	No Content
400	Invalid service definition provided in the request body	No Content
500	Failed to create a service	No Content
default	Unexpected error	ServiceStatus

(TBD) List of services running in the cluster.

GET /app/v1/services

Description

Get a list of all currently running services (response includes a minimal projection of the service info). For more details do a GET on a specific service name.

Responses

HTTP Code	Description	Schema
200	An array of services	Service array
default	Unexpected error	ServiceStatus

Get current version of the API server.

GET /app/v1/services/version

Description

Get current version of the API server.

Responses

HTTP Code	Description	Schema
200	Successful request	No Content

Update a service or upgrade the binary version of the components of a running service

PUT /app/v1/services/{service_name}

Description

Update the runtime properties of a service. Currently the following operations are supported - update lifetime, stop/start a service. The PUT operation is also used to orchestrate an upgrade of the service containers to a newer version of their artifacts (TBD).

Parameters

Type	Name	Description	Required	Schema	Default
PathParameter	service_name	Service name	true	string
BodyParameter	Service	The updated service definition. It can contain the updated lifetime of a service or the desired state (STOPPED/STARTED) of a service to initiate a start/stop operation against the specified service	true	Service

Responses

HTTP Code	Description	Schema
204	Update or upgrade was successful	No Content
404	Service does not exist	No Content
default	Unexpected error	ServiceStatus

Get details of a service.

GET /app/v1/services/{service_name}

Description

Return the details (including containers) of a running service

Parameters

Type	Name	Description	Required	Schema	Default
PathParameter	service_name	Service name	true	string

Responses

HTTP Code	Description	Schema
200	a service object	object
404	Service does not exist	No Content
default	Unexpected error	ServiceStatus

Destroy a service

DELETE /app/v1/services/{service_name}

Description

Destroy a service and release all resources. This API might have to return JSON data providing location of logs (TBD), etc.

Parameters

Type	Name	Description	Required	Schema	Default
PathParameter	service_name	Service name	true	string

Responses

HTTP Code	Description	Schema
204	Destroy was successful	No Content
404	Service does not exist	No Content
default	Unexpected error	ServiceStatus

Flex a component's number of instances.

PUT /app/v1/services/{service_name}/components/{component_name}

Description

Set a component's desired number of instanes

Parameters

Type	Name	Description	Required	Schema
PathParameter	service_name	Service name	true	string
PathParameter	component_name	Component name	true	string
BodyParameter	Component	The definition of a component which contains the updated number of instances.	true	Component

Responses

HTTP Code	Description	Schema
200	Flex was successful	No Content
404	Service does not exist	No Content
default	Unexpected error	ServiceStatus

Definitions

Artifact

Artifact of a service component. If not specified, component will just run the bare launch command and no artifact will be localized.

Name	Description	Required	Schema	Default
id	Artifact id. Examples are package location uri for tarball based services, image name for docker, name of service, etc.	true	string
type	Artifact type, like docker, tarball, etc. (optional). For TARBALL type, the specified tarball will be localized to the container local working directory under a folder named lib. For SERVICE type, the service specified will be read and its components will be added into this service. The original component with artifact type SERVICE will be removed (any properties specified in the original component will be ignored).	false	enum (DOCKER, TARBALL, SERVICE)	DOCKER
uri	Artifact location to support multiple artifact stores (optional).	false	string

Component

One or more components of the service. If the service is HBase say, then the component can be a simple role like master or regionserver. If the service is a complex business webapp then a component can be other services say Kafka or Storm. Thereby it opens up the support for complex and nested services.

Name	Description	Required	Schema
name	Name of the service component (mandatory). If Registry DNS is enabled, the max length is 63 characters. If unique component support is enabled, the max length is lowered to 44 characters.	true	string
state	The state of the component	false	ComponentState
dependencies	An array of service components which should be in READY state (as defined by readiness check), before this component can be started. The dependencies across all components of a service should be represented as a DAG.	false	string array
readiness_check	Readiness check for this component.	false	ReadinessCheck
artifact	Artifact of the component (optional). If not specified, the service level global artifact takes effect.	false	Artifact
launch_command	The custom launch command of this component (optional for DOCKER component, required otherwise). When specified at the component level, it overrides the value specified at the global level (if any).	false	string
resource	Resource of this component (optional). If not specified, the service level global resource takes effect.	false	Resource
number_of_containers	Number of containers for this component (optional). If not specified, the service level global number_of_containers takes effect.	false	integer (int64)
containers	Containers of a started component. Specifying a value for this attribute for the POST payload raises a validation error. This blob is available only in the GET response of a started service.	false	Container array
run_privileged_container	Run all containers of this component in privileged mode (YARN-4262).	false	boolean
placement_policy	Advanced scheduling and placement policies for all containers of this component.	false	PlacementPolicy
configuration	Config properties for this component.	false	Configuration
quicklinks	A list of quicklink keys defined at the service level, and to be resolved by this component.	false	string array

ComponentState

The state of the component

Name	Description	Required	Schema	Default
state	enum of the state of the component	false	enum (FLEXING, STABLE)

ConfigFile

A config file that needs to be created and made available as a volume in a service component container.

Name	Description	Required	Schema
type	Config file in the standard format like xml, properties, json, yaml, template.	false	enum (XML, PROPERTIES, JSON, YAML, TEMPLATE, HADOOP_XML)
dest_file	The path that this configuration file should be created as. If it is an absolute path, it will be mounted into the DOCKER container. Absolute paths are only allowed for DOCKER containers. If it is a relative path, only the file name should be provided, and the file will be created in the container local working directory under a folder named conf.	false	string
src_file	This provides the source location of the configuration file, the content of which is dumped to dest_file post property substitutions, in the format as specified in type. Typically the src_file would point to a source controlled network accessible file maintained by tools like puppet, chef, or hdfs etc. Currently, only hdfs is supported.	false	string
properties	A blob of key value pairs that will be dumped in the dest_file in the format as specified in type. If src_file is specified, src_file content are dumped in the dest_file and these properties will overwrite, if any, existing properties in src_file or be added as new properties in src_file.	false	object

Configuration

Set of configuration properties that can be injected into the service components via envs, files and custom pluggable helper docker containers. Files of several standard formats like xml, properties, json, yaml and templates will be supported.

Name	Description	Required	Schema
properties	A blob of key-value pairs for configuring YARN service AM.	false	object
env	A blob of key-value pairs which will be appended to the default system properties and handed off to the service at start time. All placeholder references to properties will be substituted before injection.	false	object
files	Array of list of files that needs to be created and made available as volumes in the service component containers.	false	ConfigFile array

Container

An instance of a running service container.

Name	Description	Required	Schema
id	Unique container id of a running service, e.g. container_e3751_1458061340047_0008_01_000002.	false	string
launch_time	The time when the container was created, e.g. 2016-03-16T01:01:49.000Z. This will most likely be different from cluster launch time.	false	string (date)
ip	IP address of a running container, e.g. 172.31.42.141. The IP address and hostname attribute values are dependent on the cluster/docker network setup as per YARN-4007.	false	string
hostname	Fully qualified hostname of a running container, e.g. ctr-e3751-1458061340047-0008-01-000002.examplestg.site. The IP address and hostname attribute values are dependent on the cluster/docker network setup as per YARN-4007.	false	string
bare_host	The bare node or host in which the container is running, e.g. cn008.example.com.	false	string
state	State of the container of a service.	false	ContainerState
component_instance_name	Name of the component instance that this container instance belongs to. Component instance name is named as $COMPONENT_NAME-i, where i is a monotonically increasing integer. E.g. A componet called nginx can have multiple component instances named as nginx-0, nginx-1 etc. Each component instance is backed by a container instance.	false	string
resource	Resource used for this container.	false	Resource
artifact	Artifact used for this container.	false	Artifact
privileged_container	Container running in privileged mode or not.	false	boolean

ContainerState

The current state of the container of a service.

Name	Description	Required	Schema	Default
state	enum of the state of the container	false	enum (INIT, STARTED, READY)

KerberosPrincipal

The kerberos principal info of the user who launches the service.

Name	Description	Required	Schema	Default
principal_name	The principal name of the user who launches the service.	false	string
keytab	The URI of the kerberos keytab. It supports two modes, URI starts with “hdfs://”: A path on hdfs where the keytab is stored. The keytab will be localized by YARN to each host; URI starts with “file://”: A path on the local host where the keytab is stored. It is assumed that the keytabs are pre-installed by admins before AM launches.	false	string

PlacementConstraint

Placement constraint details.

Name	Description	Required	Schema
name	An optional name associated to this constraint.	false	string
type	The type of placement.	true	PlacementType
scope	The scope of placement.	true	PlacementScope
target_tags	The name of the components that this component‘s placement policy is depending upon are added as target tags. So for affinity say, this component’s containers are requesting to be placed on hosts where containers of the target tag component(s) are running on. Target tags can also contain the name of this component, in which case it implies that for anti-affinity say, no more than one container of this component can be placed on a host. Similarly, for cardinality, it would mean that containers of this component is requesting to be placed on hosts where at least minCardinality but no more than maxCardinality containers of the target tag component(s) are running.	false	string array
node_attributes	Node attributes are a set of key:value(s) pairs associated with nodes.	false	object
node_partitions	Node partitions where the containers of this component can run.	false	string array
min_cardinality	When placement type is cardinality, the minimum number of containers of the depending component that a host should have, where containers of this component can be allocated on.	false	integer (int64)
max_cardinality	When placement type is cardinality, the maximum number of containers of the depending component that a host should have, where containers of this component can be allocated on.	false	integer (int64)

PlacementPolicy

Advanced placement policy of the components of a service.

Name	Description	Required	Schema	Default
constraints	Placement constraint details.	true	PlacementConstraint array

PlacementScope

The scope of placement for the containers of a component.

Name	Description	Required	Schema	Default
type		false	enum (NODE, RACK)

PlacementType

The type of placement - affinity/anti-affinity/affinity-with-cardinality with containers of another component or containers of the same component (self).

Name	Description	Required	Schema	Default
type		false	enum (AFFINITY, ANTI_AFFINITY, AFFINITY_WITH_CARDINALITY)

ReadinessCheck

A check to be performed to determine the readiness of a component instance (a container). If no readiness check is specified, the default readiness check will be used unless the yarn.service.default-readiness-check.enabled configuration property is set to false at the component or global level. The artifact field is currently unsupported but may be implemented in the future, enabling a pluggable helper container to support advanced use cases.

Name	Description	Required	Schema
type	DEFAULT (AM checks whether the container has an IP and optionally performs a DNS lookup for the container hostname), HTTP (AM performs default checks, plus sends a REST call to the container and expects a response code between 200 and 299), or PORT (AM performs default checks, plus attempts to open a socket connection to the container on a specified port).	true	enum (DEFAULT, HTTP, PORT)
properties	A blob of key value pairs that will be used to configure the check.	false	object
artifact	Artifact of the pluggable readiness check helper container (optional). If specified, this helper container typically hosts the http uri and encapsulates the complex scripts required to perform actual container readiness check. At the end it is expected to respond a 204 No content just like the simplified use case. This pluggable framework benefits service owners who can run services without any packaging modifications. Note, artifacts of type docker only is supported for now. NOT IMPLEMENTED YET	false	Artifact

Resource

Resource determines the amount of resources (vcores, memory, network, etc.) usable by a container. This field determines the resource to be applied for all the containers of a component or service. The resource specified at the service (or global) level can be overriden at the component level. Only one of profile OR cpu & memory are expected. It raises a validation exception otherwise.

Name	Description	Required	Schema
profile	Each resource profile has a unique id which is associated with a cluster-level predefined memory, cpus, etc.	false	string
cpus	Amount of vcores allocated to each container (optional but overrides cpus in profile if specified).	false	integer (int32)
memory	Amount of memory allocated to each container (optional but overrides memory in profile if specified). Currently accepts only an integer value and default unit is in MB.	false	string
additional	A map of resource type name to resource type information. Including value (integer), and unit (string). This will be used to specify resource other than cpu and memory. Please refer to example below.	false	object

ResourceInformation

ResourceInformation determines unit/value of resource types in addition to memory and vcores. It will be part of Resource object.

Name	Description	Required	Schema	Default
value	Integer value of the resource.	false	integer (int64)
unit	Unit of the resource, acceptable values are - p/n/u/m/k/M/G/T/P/Ki/Mi/Gi/Ti/Pi. By default it is empty means no unit.	false	string

Service

a service resource has the following attributes.

Name	Description	Required	Schema
name	A unique service name. If Registry DNS is enabled, the max length is 63 characters.	true	string
version	Version of the service.	true	string
description	Description of the service.	false	string
id	A unique service id.	false	string
artifact	The default artifact for all components of the service except the components which has Artifact type set to SERVICE (optional).	false	Artifact
resource	The default resource for all components of the service (optional).	false	Resource
launch_time	The time when the service was created, e.g. 2016-03-16T01:01:49.000Z.	false	string (date)
number_of_running_containers	In get response this provides the total number of running containers for this service (across all components) at the time of request. Note, a subsequent request can return a different number as and when more containers get allocated until it reaches the total number of containers or if a flex request has been made between the two requests.	false	integer (int64)
lifetime	Life time (in seconds) of the service from the time it reaches the STARTED state (after which it is automatically destroyed by YARN). For unlimited lifetime do not set a lifetime value.	false	integer (int64)
components	Components of a service.	false	Component array
configuration	Config properties of a service. Configurations provided at the service/global level are available to all the components. Specific properties can be overridden at the component level.	false	Configuration
state	State of the service. Specifying a value for this attribute for the PUT payload means update the service to this desired state.	false	ServiceState
quicklinks	A blob of key-value pairs of quicklinks to be exported for a service.	false	object
queue	The YARN queue that this service should be submitted to.	false	string
kerberos_principal	The principal info of the user who launches the service	false	KerberosPrincipal
docker_client_config	URI of the file containing the docker client configuration (e.g. hdfs:///tmp/config.json)	false	string

ServiceState

The current state of a service.

Name	Description	Required	Schema	Default
state	enum of the state of the service	false	enum (ACCEPTED, STARTED, STABLE, STOPPED, FAILED, FLEX)

ServiceStatus

The current status of a submitted service, returned as a response to the GET API.

Name	Description	Required	Schema
diagnostics	Diagnostic information (if any) for the reason of the current state of the service. It typically has a non-null value, if the service is in a non-running state.	false	string
state	Service state.	false	ServiceState
code	An error code specific to a scenario which service owners should be able to use to understand the failure in addition to the diagnostic information.	false	integer (int32)

Examples

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": "1.0.0",
  "description": "hello world example",
  "components" :
    [
      {
        "name": "hello",
        "number_of_containers": 2,
        "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, lifetime value of -1 means unlimited lifetime.

{
    "name": "hello-world",
    "version": "1.0.0",
    "description": "hello world example",
    "id": "application_1503963985568_0002",
    "lifetime": -1,
    "state": "STABLE",
    "components": [
        {
            "name": "hello",
            "dependencies": [],
            "state": "STABLE",
            "resource": {
                "cpus": 1,
                "memory": "256"
            },
            "configuration": {
                "properties": {},
                "env": {},
                "files": []
            },
            "quicklinks": [],
            "containers": [
                {
                    "id": "container_e03_1503963985568_0002_01_000002",
                    "ip": "10.22.8.143",
                    "hostname": "ctr-e03-1503963985568-0002-01-000002.example.site",
                    "state": "READY",
                    "launch_time": 1504051512412,
                    "bare_host": "host100.cloud.com",
                    "component_instance_name": "hello-0"
                },
                {
                    "id": "container_e03_1503963985568_0002_01_000003",
                    "ip": "10.22.8.144",
                    "hostname": "ctr-e03-1503963985568-0002-01-000003.example.site",
                    "state": "READY",
                    "launch_time": 1504051536450,
                    "bare_host": "host100.cloud.com",
                    "component_instance_name": "hello-1"
                }
            ],
            "launch_command": "./start_nginx.sh",
            "number_of_containers": 1,
            "run_privileged_container": false
        }
    ],
    "configuration": {
        "properties": {},
        "env": {},
        "files": []
    },
    "quicklinks": {}
}

Update to modify the lifetime of a service

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

PUT Request JSON

Note, irrespective of what the current lifetime value is, this update request will set the lifetime of the service to be 3600 seconds (1 hour) from the time the request is submitted. Hence, if a a service has remaining lifetime of 5 mins (say) and would like to extend it to an hour OR if an application has remaining lifetime of 5 hours (say) and would like to reduce it down to an hour, then for both scenarios you need to submit the same request below.

{
  "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"
}

Update to flex up/down the no 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

POST Request JSON

{
  "name": "hbase-app-1",
  "version": "1.0.0",
  "description": "hbase service",
  "lifetime": "3600",
  "components": [
    {
      "name": "hbasemaster",
      "number_of_containers": 1,
      "artifact": {
        "id": "hbase:latest",
        "type": "DOCKER"
      },
      "launch_command": "/usr/hdp/current/hbase-master/bin/hbase master start",
      "resource": {
        "cpus": 1,
        "memory": "2048"
      },
      "configuration": {
        "env": {
          "HBASE_LOG_DIR": "<LOG_DIR>"
        },
        "files": [
          {
            "type": "XML",
            "dest_file": "/etc/hadoop/conf/core-site.xml",
            "properties": {
              "fs.defaultFS": "${CLUSTER_FS_URI}"
            }
          },
          {
            "type": "XML",
            "dest_file": "/etc/hbase/conf/hbase-site.xml",
            "properties": {
              "hbase.cluster.distributed": "true",
              "hbase.zookeeper.quorum": "${CLUSTER_ZK_QUORUM}",
              "hbase.rootdir": "${SERVICE_HDFS_DIR}/hbase",
              "zookeeper.znode.parent": "${SERVICE_ZK_PATH}",
              "hbase.master.hostname": "hbasemaster.${SERVICE_NAME}.${USER}.${DOMAIN}",
              "hbase.master.info.port": "16010"
            }
          }
        ]
      }
    },
    {
      "name": "regionserver",
      "number_of_containers": 3,
      "unique_component_support": "true",
      "artifact": {
        "id": "hbase:latest",
        "type": "DOCKER"
      },
      "launch_command": "/usr/hdp/current/hbase-regionserver/bin/hbase regionserver start",
      "resource": {
        "cpus": 1,
        "memory": "2048"
      },
      "configuration": {
        "env": {
          "HBASE_LOG_DIR": "<LOG_DIR>"
        },
        "files": [
          {
            "type": "XML",
            "dest_file": "/etc/hadoop/conf/core-site.xml",
            "properties": {
              "fs.defaultFS": "${CLUSTER_FS_URI}"
            }
          },
          {
            "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": "${SERVICE_ZK_PATH}",
              "hbase.master.hostname": "hbasemaster.${SERVICE_NAME}.${USER}.${DOMAIN}",
              "hbase.master.info.port": "16010",
              "hbase.regionserver.hostname": "${COMPONENT_INSTANCE_NAME}.${SERVICE_NAME}.${USER}.${DOMAIN}"
            }
          }
        ]
      }
    }
  ],
  "quicklinks": {
    "HBase Master Status UI": "http://hbasemaster0.${SERVICE_NAME}.${USER}.${DOMAIN}:16010/master-status",
    "Proxied HBase Master Status UI": "http://app-proxy/${DOMAIN}/${USER}/${SERVICE_NAME}/hbasemaster/16010/"
  }
}

Create a service requesting GPUs in addition to CPUs and RAM

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

POST Request JSON

{
  "name": "hello-world",
  "version": "1.0.0",
  "description": "hello world example with GPUs",
  "components" :
    [
      {
        "name": "hello",
        "number_of_containers": 2,
        "artifact": {
          "id": "nginx:latest",
          "type": "DOCKER"
        },
        "launch_command": "./start_nginx.sh",
        "resource": {
          "cpus": 1,
          "memory": "256",
          "additional" : {
            "yarn.io/gpu" : {
              "value" : 4,
              "unit" : ""
            }
          }
        }
      }
    ]
}

Create a service with a component requesting anti-affinity placement policy

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

POST Request JSON

{
  "name": "hello-world",
  "version": "1.0.0",
  "description": "hello world example with anti-affinity",
  "components" :
    [
      {
        "name": "hello",
        "number_of_containers": 3,
        "artifact": {
          "id": "nginx:latest",
          "type": "DOCKER"
        },
        "launch_command": "./start_nginx.sh",
        "resource": {
          "cpus": 1,
          "memory": "256"
        },
        "placement_policy": {
          "constraints": [
            {
              "type": "ANTI_AFFINITY",
              "scope": "NODE",
              "target_tags": [
                "hello"
              ]
            }
          ]
        }
      }
    ]
}

GET Response JSON

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

Note, that the 3 containers will come up on 3 different nodes. If there are less than 3 NMs running in the cluster, then all 3 container requests will not be fulfilled and the service will be in non-STABLE state.

{
    "name": "hello-world",
    "version": "1.0.0",
    "description": "hello world example with anti-affinity",
    "id": "application_1503963985568_0003",
    "lifetime": -1,
    "state": "STABLE",
    "components": [
        {
            "name": "hello",
            "dependencies": [],
            "state": "STABLE",
            "resource": {
                "cpus": 1,
                "memory": "256"
            },
            "placement_policy": {
              "constraints": [
                {
                  "type": "ANTI_AFFINITY",
                  "scope": "NODE",
                  "node_attributes": {},
                  "node_partitions": [],
                  "target_tags": [
                    "hello"
                  ]
                }
              ]
            },
            "configuration": {
                "properties": {},
                "env": {},
                "files": []
            },
            "quicklinks": [],
            "containers": [
                {
                    "id": "container_e03_1503963985568_0003_01_000002",
                    "ip": "10.22.8.143",
                    "hostname": "ctr-e03-1503963985568-0003-01-000002.example.site",
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                    "component_instance_name": "hello-0"
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                    "hostname": "ctr-e03-1503963985568-0003-01-000003.example.site",
                    "state": "READY",
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                    "bare_host": "host101.cloud.com",
                    "component_instance_name": "hello-1"
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                {
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                    "ip": "10.22.8.145",
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                    "state": "READY",
                    "launch_time": 1504051536450,
                    "bare_host": "host102.cloud.com",
                    "component_instance_name": "hello-2"
                }
            ],
            "launch_command": "./start_nginx.sh",
            "number_of_containers": 1,
            "run_privileged_container": false
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    ],
    "configuration": {
        "properties": {},
        "env": {},
        "files": []
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    "quicklinks": {}
}