Reputation: 387
I have Airflow jobs, which are running fine on the EMR cluster. what I need is, let's say if I have a 4 airflow jobs which required an EMR cluster for let's say 20 min to complete the task. why not we can create an EMR cluster at DAG run time and once the job is to finish it will terminate the created an EMR cluster.
Upvotes: 6
Views: 11812
Reputation: 31
The best way to do is as below
create EMR cluster >> run spark application >> wait to complete spark application >> terminate EMR cluster
import time
from airflow.operators.python import PythonOperator
from datetime import timedelta
from airflow import DAG
from airflow.providers.amazon.aws.operators.emr_add_steps import EmrAddStepsOperator
from airflow.providers.amazon.aws.operators.emr_create_job_flow import EmrCreateJobFlowOperator
from airflow.providers.amazon.aws.operators.emr_terminate_job_flow import EmrTerminateJobFlowOperator
from airflow.providers.amazon.aws.sensors.emr_step import EmrStepSensor
# Spark-submit command for application
SPARK_APP = [
{
'Name': 'spark_app1',
'ActionOnFailure': 'CONTINUE',
'HadoopJarStep': {
'Jar': 'command-runner.jar',
'Args': [
'spark-submit',
'--deploy-mode',
'cluster',
'--master',
'yarn',
'--class',
'package_path_to_main',
'location_of_jar',
args],
},
}
]
# EMR cluster configurations
JOB_FLOW_OVERRIDES = {
'Name': 'emr_cluster_name',
'ReleaseLabel': 'emr-6.4.0',
'Applications': [{"Name": "Spark"}],
'LogUri': 's3_path_for_log',
'Instances': {
'InstanceGroups': [
{
'Name': 'Master node',
'Market': 'ON_DEMAND',
'InstanceRole': 'MASTER',
'InstanceType': 'r5.8xlarge',
'InstanceCount': 1
},
{
'Name': "Slave nodes",
'Market': 'ON_DEMAND',
'InstanceRole': 'CORE',
'InstanceType': 'r5.8xlarge',
'InstanceCount': 32
}
],
'Ec2SubnetId': 'subnet-id',
'Ec2KeyName': 'KeyPair',
'KeepJobFlowAliveWhenNoSteps': True,
'TerminationProtected': False,
"AdditionalMasterSecurityGroups": [ "security-group" ]
},
'JobFlowRole': 'EMR_EC2_DefaultRole',
'SecurityConfiguration': "SecurityConfig_name",
'ServiceRole': 'EMR_DefaultRole',
'StepConcurrencyLevel': 10,
}
# Airflow Dag defination
with DAG(
dag_id='dag_name',
default_args={
'owner': 'airflow',
'depends_on_past': False,
'email': ['email-address'],
'email_on_failure': True,
'email_on_retry': False,
},
dagrun_timeout=timedelta(hours=4),
start_date=days_ago(1),
schedule_interval='0 * * * *',
catchup=False,
tags=['example'],
) as dag:
# EMR cluster creator
cluster_creator = EmrCreateJobFlowOperator(
task_id='cluster_creator',
job_flow_overrides=JOB_FLOW_OVERRIDES,
aws_conn_id='aws_default',
emr_conn_id='emr_default',
)
# Adding step adder to run spark application
step_adder_1 = EmrAddStepsOperator(
task_id='step_adder_1',
job_flow_id="{{ task_instance.xcom_pull(task_ids='cluster_creator', key='return_value')}}",
aws_conn_id='aws_default',
steps=SPARK_APP,
trigger_rule='all_done',
)
# Adding step sensor to track the completion of step adder
step_checker_1 = EmrStepSensor(
task_id='step_checker_1',
job_flow_id="{{ task_instance.xcom_pull('cluster_creator', key='return_value') }}",
step_id="{{ task_instance.xcom_pull(task_ids='step_adder_1', key='return_value')[0] }}",
aws_conn_id='aws_default',
trigger_rule='all_done',
)
# Terminating EMR cluster if all task are completed which are running on top of cluster_remover task
cluster_remover = EmrTerminateJobFlowOperator(
task_id='cluster_remover',
job_flow_id="{{ task_instance.xcom_pull('cluster_creator', key='return_value') }}",
aws_conn_id='aws_default',
trigger_rule='all_done',
)
# defining the order of task
cluster_creator >> step_adder_1 >> step_checker_1 >> cluster_remover
Upvotes: 2
Reputation: 59
Check my implementation, DAG will create emr cluster and run the spark job against the data in s3 and terminate automatically once done.
https://beyondexperiment.com/vijayravichandran06/aws-emr-orchestrate-with-airflow/
Upvotes: 1
Reputation: 11607
Absolutely, that would be the most efficient use of resources. Let me warn you: there are a lot of details in this; I'll try to list as many as would get you going. I encourage you to add your own comprehensive answer listing any problems that you encountered and the workaround (once you are through this)
Regarding cluster creation / termination
For cluster creation and termination, you have EmrCreateJobFlowOperator
and EmrTerminateJobFlowOperator
respectively
Don't fret if you do not use AWS
SecretAccessKey
(and rely wholly on IAM
Roles); instantiating any AWS
-related hook
or operator
in Airflow
will automatically fall-back to underlying EC2
's attached IAM
Role
If your'e NOT using the EMR-Steps API for job-submission, then you'll also have to manually sense both the above operations using Sensors
. There's already a sensor for polling creation phase called EmrJobFlowSensor
and you can modify it slightly to create a sensor for termination too
You pass your cluster-config JSON in job_flow_extra
. You can also pass configs in a Connection
's (like my_emr_conn
) extra
param, but refrain from it because it often breaks SQLAlchemy
ORM loading (since its a big json
)
Regarding job submission
You either submit jobs to Emr
using EMR-Steps API, which can be done either during cluster creation phase (within the Cluster-Configs JSON) or afterwards using add_job_flow_steps()
. There's even an emr_add_steps_operator()
in Airflow
which also requires an EmrStepSensor
. You can read more about it in AWS
docs and you might also have to use command-runner.jar
For application-specific cases (like Hive
, Livy
), you can use their specific ways. For instance you can use HiveServer2Hook
to submit a Hive
job. Here's a tricky part: The run_job_flow()
call (made during cluster-creation phase) only gives you a job_flow_id
(cluster-id). You'll have to use a describe_cluster()
call using EmrHook
to obtain the private-IP of the master node. Using this you will then be able to programmatically create a Connection
(such as Hive Server 2 Thrift
connection) and use it for submitting your computations to cluster. And don't forget to delete those connections (for elegance) before completing your workflow.
Finally there's the good-old bash for interacting with cluster. For this you should also pass an EC2
key pair during cluster creation phase. Afterwards, you can programmatically create an SSH
connection and use it (with an SSHHook
or SSHOperator
) for running jobs on your cluster. Read more about SSH-stuff in Airflow
here
Particularly for submitting Spark
jobs to remote Emr
cluster, read this discussion
Upvotes: 11
Reputation: 1256
The best way to do this is probably to have a node at the root of your Airflow DAG that creates the EMR cluster, and then another node at the very end of the DAG that spins the cluster down after all of the other nodes have completed.
Upvotes: 1