Error creating ElasticSearch domain: ValidationException: EBS storage must be selected for t2.small.elasticsearch

Trying to fix this error but I can't really find anything in the docs on how to create one. Can someone point me in the right direction?

can you post the code you have at the moment?

Sorry, this is the code!

import * as pulumi from "@pulumi/pulumi";
import * as aws from "@pulumi/aws";
import { vpc } from './vpc';

const config = new pulumi.Config();

const domain = config.get("domain") || "tf-test";
const currentRegion = config.get("aws:region")

const currentCallerIdentity = pulumi.output(aws.getCallerIdentity({ async: true }));
const esSecurityGroup = new aws.ec2.SecurityGroup("es", {
    description: "Managed by Pulumi",
    ingress: [{
        cidrBlocks: [vpc.vpc.cidrBlock],
        fromPort: 443,
        protocol: "tcp",
        toPort: 443,
    }],
    vpcId: vpc.id,
});
// const esServiceLinkedRole = new aws.iam.ServiceLinkedRole("es", {
//     awsServiceName: "<http://es.amazonaws.com|es.amazonaws.com>",
// });

export const esDomain = new aws.elasticsearch.Domain("es", {
    accessPolicies: pulumi.interpolate`{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": "es:*",
            "Principal": "*",
            "Effect": "Allow",
            "Resource": "arn:aws:es:${currentRegion}:${currentCallerIdentity.accountId}:domain/${domain}/*"
        }
    ]
}
`,
    advancedOptions: {
        "rest.action.multi.allow_explicit_index": "true",
    },
    clusterConfig: {
        instanceType: "t2.small.elasticsearch", // "c5.large.elasticsearch",
    },
    elasticsearchVersion: "5.6",
    snapshotOptions: {
        automatedSnapshotStartHour: 23,
    },
    tags: {
        Domain: "TestDomain",
    },
    vpcOptions: {
        securityGroupIds: [vpc.id],
        subnetIds: vpc.privateSubnetIds,
    },
    ebsOptions: ???.
}, { 
    // dependsOn: [esServiceLinkedRole]
});