AWS EC2 Java SDK: Start an instance with custom instance type

Question

I am trying to start an EC2 instance though Java code. I added this maven dependency in my project:

https://mvnrepository.com/artifact/com.amazonaws/aws-java-sdk-ec2/1.11.308

It provides me with a class, which can be used to request starting an instance. The code is as follows:

StartInstancesRequest startReq = new StartInstancesRequest()
                .withInstanceIds(instanceID);

ec2Client.startInstances(startReq);

But, there is no with* method in StartInstancesRequest class, which takes instance type as input.

Can anyone please tell me how can I specify instance type too?

Answer 1

The startInstances call is really used to start instances that are in the stopped state - that's why it takes instance ids.

I use runInstances when I want to customize the instance. With it you can do things like:

RunInstancesRequest runInstancesRequest = new RunInstancesRequest();

runInstancesRequest.withImageId("ami-4b814f22")
                   .withInstanceType("m1.small")
                   .withMinCount(1)
                   .withMaxCount(1)
                   .withKeyName("my-key-pair")
                   .withSecurityGroups("my-security-group");

(taken directly from Run an Amazon EC2 Instance ).

This has tons of customization that you can use to configure the new instance.

Answer 2

If you don't want to use AMI and use the runInstances, why not change the instance type before you start your instance as follows

// Change the instance type
ModifyInstanceAttributeRequest modReq = new ModifyInstanceAttributeRequest()
.withInstanceType(instanceType)
.withInstanceId(instanceID);

ec2client.modifyInstanceAttribute(modReq);

// Then start your instance
StartInstancesRequest startReq = new StartInstancesRequest()
            .withInstanceIds(instanceID);

ec2Client.startInstances(startReq);