Description

Linux containers with additional capabilities fail in windows 10 - 1607 with Docker version 18.09.1, build 4c52b90 . Linux containers which require thread priority scheduling requires SYS_NICE capability. This works fine on linux but fails on windows. This is not resolved even running on privileged mode.

Steps to reproduce the issue:

1. A strip down container testing thread scheduling available @ itsgk92/set_cap_test
2. Run the container on Linux with SYS_NICE capability or privileged mode; behavior as in expected output below
3. Run the same on Windows - fails with both cap-add and privileged.

Describe the results you received:
On Windows 10 - 1607 with Docker version 18.09.1, build 4c52b90

docker run -it itsgk92/set_cap_test
pthread_setschedparam: Operation not permitted

docker run -it --cap-add SYS_NICE itsgk92/set_cap_test
pthread_setschedparam: Operation not permitted

docker run -it --privileged itsgk92/set_cap_test
pthread_setschedparam: Operation not permitted

Describe the results you expected:
On Linux with Docker version 18.09.0, build 4d60db4:

$ docker run -it itsgk92/set_cap_test
pthread_setschedparam: Operation not permitted

$ docker run -it --cap-add SYS_NICE itsgk92/set_cap_test
Scheduler settings of main thread
policy=SCHED_FIFO, priority=10

Scheduler settings in 'attr'
policy=SCHED_RR, priority=20
inheritsched is EXPLICIT

Scheduler attributes of new thread
policy=SCHED_RR, priority=20

Additional information you deem important (e.g. issue happens only occasionally):

Output of docker version:

Docker version 18.09.1, build 4c52b90

Output of docker info:

Server Version: 18.09.1
Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true
 Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host ipvlan macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 9754871865f7fe2f4e74d43e2fc7ccd237edcbce
runc version: 96ec2177ae841256168fcf76954f7177af9446eb
init version: fec3683
Security Options:
 seccomp
  Profile: default
Kernel Version: 4.9.125-linuxkit
Operating System: Docker for Windows
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 1.934GiB
Name: linuxkit-00155d561b07
ID: CIKM:WSST:4QWU:7HKG:BOPS:AYG4:2BSM:YDYT:QXTW:HNOO:5Q4M:7N2A
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): true
 File Descriptors: 23
 Goroutines: 47
 System Time: 2019-01-24T11:52:37.7840477Z
 EventsListeners: 1
Registry: https://index.docker.io/v1/
Labels:
Experimental: true
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false
Product License: Community Engine

Additional environment details (AWS, VirtualBox, physical, etc.):