docker --ulimit does not support unlimited or large numbers

[vincentwoo]

While trying to get my containers to generate core file dumps, I ran into an issue setting the ulimit high enough. Would love an explanation, as I have no idea why upping to 1000000 doesn't seem to have an effect!

$ docker run --ulimit core=999999 -t ubuntu:12.04 bash -c "ulimit -c"
976
$ docker run --ulimit core=1000000 -t ubuntu:12.04 bash -c "ulimit -c"
0
$ docker run --ulimit core=unlimited -t ubuntu:12.04 bash -c "ulimit -c"
invalid value "core=unlimited" for flag --ulimit: strconv.ParseInt: parsing "unlimited": invalid syntax
See 'docker run --help'.

running on

$ docker --version
Docker version 1.6.0, build 4749651
$ docker info
Containers: 1
Images: 555
Storage Driver: aufs
 Root Dir: /var/lib/docker/aufs
 Backing Filesystem: extfs
 Dirs: 557
 Dirperm1 Supported: false
Execution Driver: native-0.2
Kernel Version: 3.11.0-12-generic
Operating System: Ubuntu 13.10
CPUs: 2
Total Memory: 3.767 GiB
Name: ubuntu
ID: 6LST:RRCU:BKCS:Z73Y:HOMA:UUY7:RHNL:YRDY:52H6:IGID:SL3G:57BR
Registry: [https://index.docker.io/v1/]

[cpuguy83]

Quite strange.
I can confirm I'm seeing the same issue.
However, running the same basic code that Docker/libcontainer are running I cannot repro:

import (
    "log"
    "os"
    "os/exec"
    "syscall"

    "github.com/docker/docker/pkg/ulimit"
)

func main() {
    u, err := ulimit.Parse(os.Args[1])
    if err != nil {
        log.Fatal(err)
    }

    r, err := u.GetRlimit()
    if err != nil {
        log.Fatal(err)
    }

    l := &syscall.Rlimit{Max: r.Hard, Cur: r.Soft}
    if err := syscall.Setrlimit(r.Type, l); err != nil {
        log.Fatal(err)
    }
    cmd := exec.Command("/bin/sh", "-c", "ulimit -c")
    cmd.Stdout = os.Stdout
    cmd.Stderr = os.Stderr

    cmd.Run()
}

unlimited is purposefully not support since it's not a real value, it's just a constant set to a really high number.

[hqhq]

I can't reproduce, the latest master code works fine for me:

$ docker run --ulimit core=999999 -t --rm ubuntu:14.04 bash -c "ulimit -c"
976
$ docker run --ulimit core=1000000 -t --rm ubuntu:14.04 bash -c "ulimit -c"
976
$ docker run --ulimit core=10000000 -t --rm ubuntu:14.04 bash -c "ulimit -c"
9765

[mischief]

rather amusing behavior:

core@coreos_production_qemu-653-0-0-2 ~ $ docker run --ulimit nofile=1000000 -t --rm ubuntu:14.04 bash -c "ulimit -n"
FATA[0000] Error response from daemon: Cannot start container cbeb24aee366292fe9a94b5b481d8fa0c7681eefb546ef982ebaa43b036058a1: [8] System error: open /var/lib/docker/overlay/cbeb24aee366292fe9a94b5b481d8fa0c7681eefb546ef982ebaa43b036058a1/merged/dev/console: too many open files 
core@coreos_production_qemu-653-0-0-2 ~ $ docker info
Containers: 12
Images: 8
Storage Driver: overlay
 Backing Filesystem: extfs
Execution Driver: native-0.2
Kernel Version: 4.0.0
Operating System: CoreOS 653.0.0+2015-04-20-1835
CPUs: 4
Total Memory: 997.5 MiB
Name: coreos_production_qemu-653-0-0-2
ID: YURS:H7BQ:2VVN:DH22:3NUJ:S6TD:P2QT:7OWF:EPEQ:KO2K:ZD2B:CJQ2
core@coreos_production_qemu-653-0-0-2 ~ $ docker version
Client version: 1.6.0
Client API version: 1.18
Go version (client): go1.3.3
Git commit (client): 4749651-dirty
OS/Arch (client): linux/amd64
Server version: 1.6.0
Server API version: 1.18
Go version (server): go1.3.3
Git commit (server): 4749651-dirty
OS/Arch (server): linux/amd64
core@coreos_production_qemu-653-0-0-2 ~ $

[cpuguy83]

Yes, this is really weird... I wonder what commit fixed this... cc @LK4D4 @crosbymichael
If there is a 1.6.1, surely the commit that fixes this needs to be in it.

[josiasmontag]

Issue is not solved with 1.6.1.
Workaround in the meantime: Use magic -1.

$docker run --ulimit core=-1 -t --rm busybox sh -c "ulimit -c"
unlimited

[cpuguy83]

Yes, 1.6.1 only had security fixes.

[cpuguy83]

Closing since this issue is fixed on master.

[nikolai-derzhak-distillery]

-1 trick does not work anymore:

docker: Error response from daemon: json: cannot unmarshal number -1 into Go value of type uint64.

[jorge-trujillo]

Any update on this? docker-compose still returns this error:

ERROR: for elasticsearch  json: cannot unmarshal number -1 into Go value of type uint64

[nikolai-derzhak-distillery]

I use next constant as workaround:

--ulimit memlock=9223372036854775807

Comment from my code:

ulimit -1 throws error as it uint64 now in docker code

so we use 2^63-1 number as equal value

[cpuguy83]

Probably an easy fix here: https://github.com/docker/go-units/blob/master/ulimit.go#L113 to support -1 as unlimited.

[vincentwoo]

For those on this issue, setting -1 does appear to work as of Docker 1.13.