Description of problem:
Docker 1.7.0-rc1 fails to create containers with CpuShare outside the kernel allowable range.

Previous versions of Docker allowed container creation below the minimum or above the maximum and the kernel would silently adjust to be within the range (i.e. CpuShare of 1 would become 2 and CpuShare greater than 262144 would become 262144). In this commit libcontainer was changed to return errors rather than silently proceeding. This change in behavior affects all versions of the Docker Remote API, and is effectively breaking for clients who strongly tie to a specific API version.

docker version:

Client version: 1.7.0-rc1
Client API version: 1.19
Go version (client): go1.4.2
Git commit (client): 395cced
OS/Arch (client): linux/amd64
Server version: 1.7.0-rc1
Server API version: 1.19
Go version (server): go1.4.2
Git commit (server): 395cced
OS/Arch (server): linux/amd64

docker info:

Containers: 12
Images: 31
Storage Driver: devicemapper
 Pool Name: docker-202:1-131298-pool
 Pool Blocksize: 65.54 kB
 Backing Filesystem: extfs
 Data file: /dev/loop0
 Metadata file: /dev/loop1
 Data Space Used: 1.015 GB
 Data Space Total: 107.4 GB
 Data Space Available: 28.9 GB
 Metadata Space Used: 2.413 MB
 Metadata Space Total: 2.147 GB
 Metadata Space Available: 2.145 GB
 Udev Sync Supported: true
 Deferred Removal Enabled: false
 Data loop file: /var/lib/docker/devicemapper/devicemapper/data
 Metadata loop file: /var/lib/docker/devicemapper/devicemapper/metadata
 Library Version: 1.02.89-RHEL6 (2014-09-01)
Execution Driver: native-0.2
Logging Driver: json-file
Kernel Version: 3.14.35-28.38.amzn1.x86_64
Operating System: Amazon Linux AMI 2015.03
CPUs: 1
Total Memory: 996.3 MiB
Name: ip-172-31-18-169
ID: XRH7:FJA6:63ZN:AWVH:OMXN:NAV3:TRUX:5JIG:ZRTY:V5OG:GOIC:MII7

uname -a:

Linux ip-172-31-18-169 3.14.35-28.38.amzn1.x86_64 #1 SMP Wed Mar 11 22:50:37 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Environment details (AWS, VirtualBox, physical, etc.): AWS

How reproducible:
Reproduceable everywhere I tested, including an EC2 instance running the Amazon Linux AMI and on a VM on my desktop running Ubuntu.

Steps to Reproduce:

1. Start the Docker 1.7.0-rc1 daemon
2. Attempt to create a container with CpuShare below the minimum with a 1.19
   client and watch it fail: sudo ./docker-1.7.0-rc1 run -c 1 busybox
3. Attempt to create a container with CpuShare below the minimum with an older
   client and watch it fail: sudo docker run -c 1 busybox

Actual Results:
Container fails to run with both a 1.19 client and a client speaking an older
API

Expected Results:
Container fails to run with a >1.19 client but succeeds with a client speaking
an older API

Additional info: