在AWS EMR中,可以使用AWS Step Functions来解决多个作业之间的依赖竞争。AWS Step Functions是一种服务器无状态的工作流服务,可以协调和管理多个作业之间的依赖关系。
以下是一个使用AWS Step Functions来解决多个作业之间的依赖竞争的代码示例:
首先,创建一个Step Functions状态机定义,定义作业之间的依赖关系和执行顺序。例如,以下是一个包含三个作业的状态机定义:
{
"Comment": "EMR Job Dependency Competition",
"StartAt": "Job1",
"States": {
"Job1": {
"Type": "Task",
"Resource": "arn:aws:states:::elasticmapreduce:createCluster.sync",
"Parameters": {
"Name": "Job1",
"Instances": {
"InstanceGroups": [
{
"Name": "Master",
"InstanceRole": "MASTER",
"InstanceType": "m5.xlarge",
"InstanceCount": 1
}
]
},
"Applications": [
{
"Name": "Spark"
}
],
"Steps": [
{
"Name": "Job1Step",
"ActionOnFailure": "TERMINATE_CLUSTER",
"HadoopJarStep": {
"Jar": "s3://path/to/job1.jar",
"Args": [
"arg1",
"arg2"
]
}
}
]
},
"Next": "Job2"
},
"Job2": {
"Type": "Task",
"Resource": "arn:aws:states:::elasticmapreduce:createCluster.sync",
"Parameters": {
"Name": "Job2",
"Instances": {
"InstanceGroups": [
{
"Name": "Master",
"InstanceRole": "MASTER",
"InstanceType": "m5.xlarge",
"InstanceCount": 1
}
]
},
"Applications": [
{
"Name": "Spark"
}
],
"Steps": [
{
"Name": "Job2Step",
"ActionOnFailure": "TERMINATE_CLUSTER",
"HadoopJarStep": {
"Jar": "s3://path/to/job2.jar",
"Args": [
"arg1",
"arg2"
]
}
}
]
},
"Next": "Job3"
},
"Job3": {
"Type": "Task",
"Resource": "arn:aws:states:::elasticmapreduce:createCluster.sync",
"Parameters": {
"Name": "Job3",
"Instances": {
"InstanceGroups": [
{
"Name": "Master",
"InstanceRole": "MASTER",
"InstanceType": "m5.xlarge",
"InstanceCount": 1
}
]
},
"Applications": [
{
"Name": "Spark"
}
],
"Steps": [
{
"Name": "Job3Step",
"ActionOnFailure": "TERMINATE_CLUSTER",
"HadoopJarStep": {
"Jar": "s3://path/to/job3.jar",
"Args": [
"arg1",
"arg2"
]
}
}
]
},
"End": true
}
}
}
然后,使用AWS Step Functions的Java SDK将状态机定义作为输入创建一个状态机:
import software.amazon.awssdk.services.sfn.SfnClient;
import software.amazon.awssdk.services.sfn.model.CreateStateMachineRequest;
import software.amazon.awssdk.services.sfn.model.CreateStateMachineResponse;
public class CreateStateMachine {
public static void main(String[] args) {
SfnClient sfnClient = SfnClient.builder().build();
String stateMachineDefinition = "{...}";
CreateStateMachineRequest createStateMachineRequest = CreateStateMachineRequest.builder()
.name("EMRJobDependency")
.definition(stateMachineDefinition)
.roleArn("arn:aws:iam::123456789012:role/service-role/EMRJobDependencyRole")
.type("STANDARD")
.build();
CreateStateMachineResponse createStateMachineResponse = sfnClient.createStateMachine(createStateMachineRequest);
String stateMachineArn = createStateMachineResponse.stateMachineArn();
System.out.println("State machine created with ARN: " + stateMachineArn);
}
}
``