Created attachment 691782 [details]
Patch file for the code fix

Description of problem:
AWS EC2 API reference for RunInstances and RegisterImage:

http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-query-RunInstances.html
http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-query-RegisterImage.html

As per the EC2 API reference syntax for the request parameter to suppress a device mapping is BlockDeviceMapping.n.NoDevice. 

Line number 128 in boto script blockdevicemapping.py constructs this request parameter incorrectly. It is of the form BlockDeviceMapping.Ebs.n.NoDevice where the "Ebs." substring is the additional element. EC2 fails to recognize the request parameter constructed by boto and therefore fails the RegisterImage/RunInstances request

Version-Release number of selected component (if applicable):
boto-2.8.0

How reproducible:
always

Steps to Reproduce:
Used ipython to reproduce the issue. Every step is followed by the corresponding ipython operation

1. Create an AWS EC2 account. Using boto scripts establish a connection to EC2. Bump up the debug level.
In [46]: from boto import ec2
In [47]: ec2=ec2.EC2Connection(aws_access_key_id='myaccesskey', aws_secret_access_key='mysecretkey',host='https://ec2.us-east-1.amazonaws.com')

2. Create an instance of "BlockDeviceType" with no_device=True.
In [48]: bdt = BlockDeviceType(no_device=True)

3. Initialize an instance of "BlockDeviceMapping" using the "BlockDeviceType" object created above.
In [49]: bdm = BlockDeviceMapping()
In [50]: bdm['/dev/sda1']=bdt

4. Register a boot from ebs image using the above objects. 
In [51]: ec2.register_image(name='bfebs1',root_device_name='/dev/sda1',block_device_map=bdm)

Dump from the above request, notice the syntax of NoDevice request parameter

send: 'POST / HTTP/1.1\r\nHost: ec2.us-east-1.amazonaws.com\r\nAccept-Encoding: identity\r\nContent-Length: 396\r\nContent-Type: application/x-www-form-urlencoded; charset=UTF-8\r\nUser-Agent: Boto/2.8.0 (linux2)\r\n\r\n'
send: 'AWSAccessKeyId=myaccesskey=RegisterImage&BlockDeviceMapping.1.DeviceName=%2Fdev%2Fsda1&BlockDeviceMapping.1.Ebs.DeleteOnTermination=false&BlockDeviceMapping.1.Ebs.NoDevice=true&Name=bfebs1&RootDeviceName=%2Fdev%2Fsda1&SignatureMethod=HmacSHA256&SignatureVersion=2&Timestamp=2013-02-01T22%3A00%3A54Z&Version=2012-06-01&Signature=somerandomcharacters'

  
Actual results:
EC2 rejects this request as it does not recognize the request parameter "NoDevice". The error response from EC2 is:

EC2ResponseError: 400 Bad Request
<?xml version="1.0" encoding="UTF-8"?>
<Response><Errors><Error><Code>UnknownParameter</Code><Message>The parameter NoDevice is not recognized</Message></Error></Errors><RequestID>71fc7bb5-0ad1-40d0-ab8e-bba853e4ed81</RequestID></Response>


Expected results:

Same operation using ec2 command line tools, notice the syntax of NoDevice request parameter

# ec2-register -n swathibfebs1 --root-device-name /dev/sda1 --block-device-mapping /dev/sda1=none --verbose
Setting User-Agent to [ec2-api-tools 1.6.6.3]
2013-02-01 14:26:00,577 [main] DEBUG org.apache.http.wire  - >> "POST / HTTP/1.1[\r][\n]"
2013-02-01 14:26:00,578 [main] DEBUG org.apache.http.wire  - >> "Host: ec2.us-east-1.amazonaws.com[\r][\n]"
2013-02-01 14:26:00,578 [main] DEBUG org.apache.http.wire  - >> "User-Agent: ec2-api-tools 1.6.6.3[\r][\n]"
2013-02-01 14:26:00,579 [main] DEBUG org.apache.http.wire  - >> "Content-Type: application/x-www-form-urlencoded; charset=utf-8[\r][\n]"
2013-02-01 14:26:00,579 [main] DEBUG org.apache.http.wire  - >> "Content-Length: 351[\r][\n]"
2013-02-01 14:26:00,579 [main] DEBUG org.apache.http.wire  - >> "Connection: Keep-Alive[\r][\n]"
2013-02-01 14:26:00,579 [main] DEBUG org.apache.http.wire  - >> "[\r][\n]"
2013-02-01 14:26:00,579 [main] DEBUG org.apache.http.wire  - >> "Name=swathibfebs1&RootDeviceName=%2Fdev%2Fsda1&Action=RegisterImage&SignatureMethod=HmacSHA256&BlockDeviceMapping.1.DeviceName=%2Fdev%2Fsda1&AWSAccessKeyId=myaccesskey&SignatureVersion=2&BlockDeviceMapping.1.NoDevice=&Version=2012-12-01&Signature=somerandomcharacters&Timestamp=2013-02-01T22%3A25%3A59.899Z"


Additional info:

Submitted a pull request with the code fix.