spotty.sh

#!/usr/bin/env bash
AWS_CLI="aws --region $AWS_REGION"

PRICE=0.2
USER_NAME=#USERNAME#
KEY_NAME=#KEY NAME#
SECURITY_GROUP_ID=#SECURITY GROUP#
SUBNET_ID=#SUBNET#
VOLUME_SIZE=40
INSTANCE_TYPE=t2.2xlarge
BLOCK_DURATION_MINUTES=300

# Ubuntu (ubuntu-bionic-18.04-amd64-server-20180912)
IMAGE_ID=ami-0bdf93799014acdc4
SNAPSHOT_ID=snap-0607841ca97e79815

SPEC=$(cat <<EOF
{
  "ImageId": "$IMAGE_ID",
  "InstanceType": "$INSTANCE_TYPE",
  "SubnetId": "$SUBNET_ID",
  "KeyName": "$KEY_NAME",
  "BlockDeviceMappings": [
    {
      "DeviceName": "/dev/sda1",
      "Ebs": {
        "DeleteOnTermination": true,
        "VolumeType": "gp2",
        "VolumeSize": $VOLUME_SIZE,
        "SnapshotId": "$SNAPSHOT_ID"
      }
    }
  ],
  "SecurityGroupIds": [
    "$SECURITY_GROUP_ID"
  ]
}
EOF
)

VALID_UNTIL=$(date -v +10M +%s)

OUTPUT=$($AWS_CLI ec2 request-spot-instances --valid-until $VALID_UNTIL --instance-count 1 --block-duration-minutes $BLOCK_DURATION_MINUTES --type "one-time" --spot-price $PRICE --launch-specification "$SPEC")
if [ $? -ne 0 ]; then
    echo "Could not request spot instance: $OUTPUT"
    exit;
fi

SPOT_INSTANCE_REQUEST_ID=$(echo $OUTPUT|jq -r '.SpotInstanceRequests[0].SpotInstanceRequestId')

while true; do
    OUTPUT=$($AWS_CLI ec2 describe-spot-instance-requests --query "SpotInstanceRequests[?SpotInstanceRequestId=='$SPOT_INSTANCE_REQUEST_ID']")
    if [ $? -ne 0 ]; then
        echo "Error retrieving spot instance requests: $OUTPUT"
        exit;
    fi

    STATUS=$(echo $OUTPUT| jq -r '.[0].Status.Code')
    if [[ "$STATUS" == 'fulfilled' ]]; then
        INSTANCE_ID=$(echo $OUTPUT| jq -r '.[0].InstanceId')
        break
    fi

    echo "Waiting for fullfillment: $STATUS"
    sleep 1
done

OUTPUT=$($AWS_CLI ec2 create-tags --resources $SPOT_INSTANCE_REQUEST_ID $INSTANCE_ID --tags 'Key=SPOT,Value=SPOT')
if [ $? -ne 0 ]; then
    echo "Error tagging instance ($INSTANCE_ID) for spot request ($SPOT_INSTANCE_REQUEST_ID): $OUTPUT"
    exit;
fi

OUTPUT=$($AWS_CLI ec2 describe-instances --instance-id $INSTANCE_ID)
if [ $? -ne 0 ]; then
    echo "Error retrieving instance information: $OUTPUT"
    exit;
fi

PUBLIC_IP=$(echo $OUTPUT | jq -r '.Reservations[].Instances[0].NetworkInterfaces[0].Association.PublicIp')

echo "Spot instance ready, connect using: ssh $USER_NAME@$PUBLIC_IP"