Runtime constraints on CPU and memory with docker containers
You cannot change that inside the running container, you would have to do that on your host.
How you do that on the host depends on your host-os, on Linux I suggest to take a look a cgroups, thats how docker internally restricts containers.
On ubuntu you could use the cgroup manager cgm (tried it on ubuntu 15.04).
- create a new cgroup for cpu, move the process (e.g. 28433) to it and set a value
> # cgm create cpu dudecpu > # cgm movepid cpu dudecpu 28433 > # cgm setvalue cpu dudecpu cpu.shares 512
- create a new cgroup for the memory move the process (e.g. 28433) to it and set a value
> cgm create memory dudemem> cgm movepid memory dudemem 28433> cgm setvalue memory dudemem memory.limit_in_bytes 1000000000
- check where your new cgroups are and look into these directories, you'll find all the properties of the cgroup there.
> find /sys/fs/cgroup/ -name "dude*"> /sys/fs/cgroup/memory/user.slice/user-1000.slice/session-c3.scope/dudemem> /sys/fs/cgroup/cpu,cpuacct/user.slice/user-1000.slice/session-c3.scope/dudecpu