user_data not working in request_spot_instances (base64 encoding)

When attempting to spin up a spot instance, I get as far as pending evaluation, and once that completes I get a bad-parameters error, related to the user_data not being base64-encoded:

error message:

            <fault>
                <code>Client.InvalidParameterValue</code>
                <message>Invalid BASE64 encoding of user data (400 response code)</message>
            </fault>

If I leave out the user_data, it fulfills the spot request, and I get a spot instance with no issues.

Also, this same user_data string works fine when running create_instances (on-demand).

request_spot_instance call:

ec2.meta.client.request_spot_instances(
                    SpotPrice=max_spot_price,
                    InstanceCount=int(instance_count),
                    LaunchSpecification={
                        'InstanceType': instance_type,
                        'ImageId': ami_id,
                        'KeyName': key_name,
                        'SecurityGroupIds': security_groups,
                        'UserData': user_data,
                        'SubnetId': subnet_id,
                        'IamInstanceProfile': {
                            'Name': instance_profile_name
                        },
                        'Monitoring': {
                            'Enabled': True
                        }
                    }
                )

create_instance call:

ec2.create_instances(
                    ImageId=ami_id,
                    SubnetId=subnet_id,
                    KeyName=key_name,
                    InstanceType=instance_type,
                    SecurityGroupIds=security_groups,
                    MinCount=int(instance_count),
                    MaxCount=int(instance_count),
                    IamInstanceProfile={
                        'Name': instance_profile_name
                    },
                    Monitoring={'Enabled': True},
                    UserData=user_data
                )

Full Error Message:

...
        <item>
            <spotInstanceRequestId>sir-********</spotInstanceRequestId>
            <spotPrice>1.504000</spotPrice>
            <type>one-time</type>
            <state>failed</state>
            <fault>
                <code>Client.InvalidParameterValue</code>
                <message>Invalid BASE64 encoding of user data (400 response code)</message>
            </fault>
            <status>
                <code>bad-parameters</code>
                <updateTime>2015-11-16T14:45:27.000Z</updateTime>
                <message>Your Spot request failed due to bad parameters.</message>
            </status>
            <launchSpecification>
                <imageId>ami-********</imageId>
                <keyName>********</keyName>
                <groupSet>
                    <item>
                        <groupId>sg-41ba1326</groupId>
                        <groupName>aolp-dev-us-east-1-PrivateNetworkSG-X9G897DEU9FD</groupName>
                    </item>
                </groupSet>
                <instanceType>c3.4xlarge</instanceType>
                <placement>
                    <availabilityZone>us-east-1a</availabilityZone>
                </placement>
                <monitoring>
                    <enabled>true</enabled>
                </monitoring>
                <subnetId>subnet-637b4e14</subnetId>
                <iamInstanceProfile>
                    <name>********</name>
                </iamInstanceProfile>
            </launchSpecification>
            <createTime>2015-11-16T14:43:03.000Z</createTime>
            <productDescription>Windows</productDescription>
        </item>
...

Any help would be greatly appreciated.

[maciejjaskowski]

For the record, that’s a way to do this:

base64.b64encode(user_data.encode("ascii")).decode('ascii')

[JacobTaylor-RCC]

Ah, I see, one issue has been hit often enough to get its own pullout to make it apparent, the other has not.