​
Set your AWS region 

REGION="us-west-2"

​
Creating the subnet

First, we need to know what VPC to create the subnet on, so let’s describe the VPCs in the region where we want to create the Omni machines. 
aws ec2 describe-vpcs --region $REGION
Output: 

{
    "Vpcs": [
        {
            "CidrBlock": "172.31.0.0/16",
            "DhcpOptionsId": "dopt-0238fea7541672af0",
            "State": "available",
            "VpcId": "vpc-04ea926270c55d724",
            "OwnerId": "753518523373",
            "InstanceTenancy": "default",
            "CidrBlockAssociationSet": [
                {
                    "AssociationId": "vpc-cidr-assoc-0e518f7ac9d02907d",
                    "CidrBlock": "172.31.0.0/16",
                    "CidrBlockState": {
                        "State": "associated"
                    }
                }
            ],
            "IsDefault": true
        }
    ]
}
Note the VpcId (vpc-04ea926270c55d724). Now, create a subnet on that VPC with a CIDR block that is within the CIDR block of the VPC. In the above example, as the VPC has a CIDR block of 172.31.0.0/16, we can use 172.31.128.0/20. 
$ aws ec2 create-subnet \
    --vpc-id vpc-04ea926270c55d724 \
    --region us-west-2 \
    --cidr-block 172.31.128.0/20
Output: 
{
    "Subnet": {
        "AvailabilityZone": "us-west-2c",
        "AvailabilityZoneId": "usw2-az3",
        "AvailableIpAddressCount": 4091,
        "CidrBlock": "172.31.192.0/20",
        "DefaultForAz": false,
        "MapPublicIpOnLaunch": false,
        "State": "available",
        "SubnetId": "subnet-04f4d6708a2c2fb0d",
        "VpcId": "vpc-04ea926270c55d724",
        "OwnerId": "753518523373",
        "AssignIpv6AddressOnCreation": false,
        "Ipv6CidrBlockAssociationSet": [],
        "SubnetArn": "arn:aws:ec2:us-west-2:753518523373:subnet/subnet-04f4d6708a2c2fb0d",
        "EnableDns64": false,
        "Ipv6Native": false,
        "PrivateDnsNameOptionsOnLaunch": {
            "HostnameType": "ip-name",
            "EnableResourceNameDnsARecord": false,
            "EnableResourceNameDnsAAAARecord": false
        }
    }
}
Note the SubnetID (subnet-04f4d6708a2c2fb0d).

​
Create the Security Group 

aws ec2 create-security-group \
    --region $REGION \
    --group-name omni-aws-sg \
    --description "Security Group for Omni EC2 instances"
Output 
{   
     "GroupId": "sg-0b2073b72a3ca4b03"
}
Note the GroupId (sg-0b2073b72a3ca4b03). Allow all internal traffic within the same security group, so that Kubernetes applications can talk to each other on different machines: 
aws ec2 authorize-security-group-ingress \
    --region $REGION \
    --group-name omni-aws-sg \
    --protocol all \
    --port 0 \
    --source-group omni-aws-sg

​
Creating the bootable AMI

To do so, log in to your Omni account, and, from the Omni overview page, select “Download Installation Media”. Select “AWS AMI (amd64)” or “AWS AMI (arm64)”, as appropriate for your desired EC2 instances. (Most are amd64.) Click “Download”, and the AMI will be downloaded to you local machine. Extract the downloaded aws-amd64.tar.gz Then copy the disk.raw file to S3. We need to create a bucket, copy the image file to it, import it as a snapshot, then register an AMI image from it.

​
Create S3 bucket 

REGION="us-west-2"
aws s3api create-bucket \
    --bucket <bucket name> \
    --create-bucket-configuration LocationConstraint=$REGION \
    --acl private

​
Copy image file to the bucket 

aws s3 cp disk.raw s3://<bucket name>/omni-aws.raw

​
Import the image as a snapshot 

aws ec2 import-snapshot \
    --region $REGION \
    --description "Omni AWS" \
    --disk-container "Format=raw,UserBucket={S3Bucket=<bucket name>,S3Key=omni-aws.raw}"
Output: 
{
    "Description": "Omni AWS",
    "ImportTaskId": "import-snap-1234567890abcdef0",
    "SnapshotTaskDetail": {
        "Description": "Omni AWS",
        "DiskImageSize": "0.0",
        "Format": "RAW",
        "Progress": "3",
        "Status": "active",
        "StatusMessage": "pending"
        "UserBucket": {
            "S3Bucket": "<bucket name>",
            "S3Key": "omni-aws.raw"
        }
    }
}
Check the status of the import with: 
aws ec2 describe-import-snapshot-tasks \
    --region $REGION \
    --import-task-ids
Output: 
While the import is in progress:
{
    "ImportSnapshotTasks": [
        {
            "Description": "Omni AWS",
            "ImportTaskId": "import-snap-1234567890abcdef0",
            "SnapshotTaskDetail": {
                "Description": "Omni AWS",
                "DiskImageSize": "705638400.0",
                "Format": "RAW",
                "Progress": "42",
                "Status": "active",
                "StatusMessage": "downloading/converting",
                "UserBucket": {
                    "S3Bucket": "<bucket name>",
                    "S3Key": "omni-aws.raw"
                }
            }
        }
    ]
}

Once completed:
{
    "ImportSnapshotTasks": [
        {
            "Description": "Omni AWS",
            "ImportTaskId": "import-snap-1234567890abcdef0",
            "SnapshotTaskDetail": {
                "DiskImageSize": 8589934592.0,
                "Format": "raw",
                "SnapshotId": "snap-056a7e086ecf7b452",
                "Status": "completed",
                "UserBucket": {
                    "S3Bucket": "<bucket name>",
                    "S3Key": "omni-aws.raw"
                }
            },
            "Tags": []
        }
    ]
}
Once the Status is completed note the SnapshotId (snap-056a7e086ecf7b452).

​
Register the Image 

aws ec2 register-image \
    --region $REGION \
    --block-device-mappings "DeviceName=/dev/xvda,VirtualName=talos,Ebs={DeleteOnTermination=true,SnapshotId=$SNAPSHOT,VolumeSize=8,VolumeType=gp2}" \
    --root-device-name /dev/xvda \
    --virtualization-type hvm \
    --architecture x86_64 \
    --ena-support \
    --name omni-aws-ami
Output: 
{
    "ImageId": "ami-07961b424e87e827f"
}
Note the ImageId (ami-07961b424e87e827f).

​
Create EC2 instances from the AMI

Now, using the AMI we created, along with the security group created above, provision EC2 instances: 
 aws ec2 run-instances \
    --region  $REGION \
    --image-id ami-07961b424e87e827f \
    --count 1 \
    --instance-type t3.small   \
    --subnet-id subnet-0a7f5f87f62c301ea \
    --security-group-ids $SECURITY_GROUP   \
    --associate-public-ip-address \
    --tag-specifications "ResourceType=instance,Tags=[{Key=Name,Value=omni-aws-ami}]" \
    --instance-market-options '{"MarketType":"spot"}'