Podman: panic on `podman run --rootfs`

Created on 14 Mar 2019 · 13Comments · Source: containers/podman

Is this a BUG REPORT or FEATURE REQUEST? (leave only one on its own line)

/kind bug

Description

migrating old services from nspawn machines to podman containers.
Trying to use the --rootfs flag.

Steps to reproduce the issue:

podman run -it --rm --rootfs /var/lib/machines/mymachine

Describe the results you received:

[root@knob] /var/lib/machines/bananaboat.usersys# podman run -it --rm --privileged --rootfs $(pwd) 
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x80 pc=0x113876a]

goroutine 1 [running]:
github.com/containers/libpod/libpod.(*Container).setupStorage(0xc000543bc0, 0x1854fa0, 0xc0000be048, 0x0, 0x0)
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/libpod/container_internal.go:340 +0x6fa
github.com/containers/libpod/libpod.(*Runtime).newContainer(0xc000224540, 0x1854fa0, 0xc0000be048, 0xc00058a500, 0xc00058aa80, 0x10, 0x10, 0x0, 0x0, 0x0)
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/libpod/runtime_ctr.go:161 +0x70f
github.com/containers/libpod/libpod.(*Runtime).NewContainer(0xc000224540, 0x1854fa0, 0xc0000be048, 0xc00058a500, 0xc00058aa80, 0x10, 0x10, 0x0, 0x0, 0x0)
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/libpod/runtime_ctr.go:46 +0xe4
main.createContainerFromCreateConfig(0xc000224540, 0xc0000f6580, 0x1854fa0, 0xc0000be048, 0x0, 0x0, 0x0, 0xc0000f6580)
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/cmd/podman/create.go:896 +0x14b
main.createContainer(0x27ca820, 0xc000224540, 0x0, 0x0, 0x0, 0x0)
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/cmd/podman/create.go:172 +0x222
main.runCmd(0x27ca820, 0x0, 0x0)
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/cmd/podman/run.go:68 +0x123
main.glob..func48(0x262b040, 0xc00047f9a0, 0x1, 0x5, 0x0, 0x0)
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/cmd/podman/run.go:32 +0x7f
github.com/containers/libpod/vendor/github.com/spf13/cobra.(*Command).execute(0x262b040, 0xc0000c6020, 0x5, 0x5, 0x262b040, 0xc0000c6020)
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/vendor/github.com/spf13/cobra/command.go:762 +0x473
github.com/containers/libpod/vendor/github.com/spf13/cobra.(*Command).ExecuteC(0x262bc20, 0x6, 0x27f0b80, 0xc0001a6f00)
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/vendor/github.com/spf13/cobra/command.go:852 +0x2fd
github.com/containers/libpod/vendor/github.com/spf13/cobra.(*Command).Execute(0x262bc20, 0xc000146370, 0xc0000ac058)
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/vendor/github.com/spf13/cobra/command.go:800 +0x2b
main.main()
        /builddir/build/BUILD/libpod-0ad9b6bf2aea4ba37e8c9738feabec61343ba175/_build/src/github.com/containers/libpod/cmd/podman/main.go:225 +0x3c

Describe the results you expected:

Really unsure

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

Output of podman version:

Version:            1.1.2
RemoteAPI Version:  1
Go Version:         go1.11.5
Git Commit:         a95a49d3038462d033f84ac314ec8a3064a99cff
Built:              Tue Mar  5 13:10:31 2019
OS/Arch:            linux/amd64

Output of podman info --debug:

debug:
  compiler: gc
  git commit: a95a49d3038462d033f84ac314ec8a3064a99cff
  go version: go1.11.5
  podman version: 1.1.2
host:
  BuildahVersion: 1.7.1
  Conmon:
    package: podman-1.1.2-1.git0ad9b6b.fc29.x86_64
    path: /usr/libexec/podman/conmon
    version: 'conmon version 1.12.0-dev, commit: a95a49d3038462d033f84ac314ec8a3064a99cff'
  Distribution:
    distribution: fedora
    version: "29"
  MemFree: 3888041984
  MemTotal: 16645263360
  OCIRuntime:
    package: runc-1.0.0-68.dev.git6635b4f.fc29.x86_64
    path: /usr/bin/runc
    version: |-
      runc version 1.0.0-rc6+dev
      commit: ef9132178ccc3d2775d4fb51f1e431f30cac1398-dirty
      spec: 1.0.1-dev
  SwapFree: 8388079616
  SwapTotal: 8392798208
  arch: amd64
  cpus: 12
  hostname: knob.usersys.redhat.com
  kernel: 4.20.14-200.fc29.x86_64
  os: linux
  rootless: false
  uptime: 25h 59m 31.69s (Approximately 1.04 days)
insecure registries:
  registries:
  - localhost:5000
  - docker.usersys.redhat.com
registries:
  registries:
  - docker.io
  - registry.fedoraproject.org
  - quay.io
  - registry.access.redhat.com
  - registry.centos.org
store:
  ConfigFile: /etc/containers/storage.conf
  ContainerStore:
    number: 7
  GraphDriverName: overlay
  GraphOptions:
  - overlay.mountopt=nodev
  GraphRoot: /var/lib/containers/storage
  GraphStatus:
    Backing Filesystem: xfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Using metacopy: "false"
  ImageStore:
    number: 24
  RunRoot: /var/run/containers/storage
  VolumePath: /var/lib/containers/storage/volumes

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

kinbug

Source

vbatts

All 13 comments

Oh dear. I honestly forgot we even implemented that flag.
@rhatdan @giuseppe Do we want to look into just deprecating --rootfs or is it worth supporting?

mheon on 14 Mar 2019

😕1 👎1

I find it useful.

I was playing with containerd and they have exactly the same feature --rootfs for unmanaged images

giuseppe on 14 Mar 2019

👍1

PR here: https://github.com/containers/libpod/pull/2656

giuseppe on 14 Mar 2019

Cool. #2656 fixes the nil pointer.
Perhaps --rootfs= could use more docs. I think it is a very useful, probably not widely known feature.

vbatts on 2 Apr 2019

👍1

Yes I think it could be a cool blog on this. @giuseppe Would you like to write one?

rhatdan on 2 Apr 2019

yes it is already on my TODO list, now just need to prioritize it :-)

giuseppe on 2 Apr 2019

Cheers guys!

Is this flag still supported?

smosciat@simo:~/go/src/github.com/containers/libpod$ ./bin/podman version
ERRO[0000] User-selected graph driver "vfs" overwritten by graph driver "overlay" from database - delete libpod local files to resolve 
Version:            1.7.1-dev
RemoteAPI Version:  1
Go Version:         go1.13.7
Git Commit:         9be64300d46341ab345f8c760b7a79cced7db3f9-dirty
Built:              Thu Jan 30 16:55:28 2020
OS/Arch:            linux/amd64
smosciat@simo:~/go/src/github.com/containers/libpod$ ./bin/podman --rootfs=/home/smosciat/tmp/redis6_rootfs/
Error: unknown flag: --rootfs

We are having some internal discussion and knowing the plan for this specific features would help us.

siscia on 7 Feb 2020

@siscia, it's podman run --rootfs.

vrothberg on 7 Feb 2020

Awww many thanks!

Actually how do I use it?

$ ./bin/podman run --rootfs /home/smosciat/tmp/redis6_rootfs
Error: args must not be empty: OCI runtime error

Where /home/smosciat/tmp/redis6_rootfs is a directory that contains an exploded filesystem generated using Singularity.

$ ll /home/smosciat/tmp/redis6_rootfs
total 92
drwxr-xr-x 23 smosciat smosciat 4096 Feb  7 10:10 ./
drwxr-xr-x 10 smosciat smosciat 4096 Feb  7 10:10 ../
drwxr-xr-x  2 smosciat smosciat 4096 Jan 30 01:00 bin/
drwxr-xr-x  2 smosciat smosciat 4096 Nov 10 13:17 boot/
drwxr-xr-x  2 smosciat smosciat 4096 Feb  1 20:18 data/
drwxr-xr-x  2 smosciat smosciat 4096 Jan 30 01:00 dev/
lrwxrwxrwx  1 smosciat smosciat   36 Feb  7 10:10 environment -> .singularity.d/env/90-environment.sh*
drwxr-xr-x 28 smosciat smosciat 4096 Feb  7 10:10 etc/
lrwxrwxrwx  1 smosciat smosciat   27 Feb  7 10:10 .exec -> .singularity.d/actions/exec*
drwxr-xr-x  2 smosciat smosciat 4096 Nov 10 13:17 home/
drwxr-xr-x  8 smosciat smosciat 4096 Feb  1 20:18 lib/
drwxr-xr-x  2 smosciat smosciat 4096 Jan 30 01:00 lib64/
drwxr-xr-x  2 smosciat smosciat 4096 Jan 30 01:00 media/
drwxr-xr-x  2 smosciat smosciat 4096 Jan 30 01:00 mnt/
drwxr-xr-x  2 smosciat smosciat 4096 Jan 30 01:00 opt/
drwxr-xr-x  2 smosciat smosciat 4096 Nov 10 13:17 proc/
drwx------  2 smosciat smosciat 4096 Feb  1 20:15 root/
drwxr-xr-x  3 smosciat smosciat 4096 Jan 30 01:00 run/
lrwxrwxrwx  1 smosciat smosciat   26 Feb  7 10:10 .run -> .singularity.d/actions/run*
drwxr-xr-x  2 smosciat smosciat 4096 Jan 30 01:00 sbin/
lrwxrwxrwx  1 smosciat smosciat   28 Feb  7 10:10 .shell -> .singularity.d/actions/shell*
lrwxrwxrwx  1 smosciat smosciat   24 Feb  7 10:10 singularity -> .singularity.d/runscript*
drwxr-xr-x  5 smosciat smosciat 4096 Feb  7 10:10 .singularity.d/
drwxr-xr-x  2 smosciat smosciat 4096 Jan 30 01:00 srv/
drwxr-xr-x  2 smosciat smosciat 4096 Nov 10 13:17 sys/
lrwxrwxrwx  1 smosciat smosciat   27 Feb  7 10:10 .test -> .singularity.d/actions/test*
drwxrwxrwt  2 smosciat smosciat 4096 Feb  1 20:18 tmp/
drwxr-xr-x 10 smosciat smosciat 4096 Jan 30 01:00 usr/
drwxr-xr-x 11 smosciat smosciat 4096 Jan 30 01:00 var/

siscia on 7 Feb 2020

Error: args must not be empty: OCI runtime error

I assume that runc/crun are complaining because they do not know what do execute, so we need to specify a command:
$ ./bin/podman run --rootfs /home/smosciat/tmp/redis6_rootfs /usr/bin/ls for instance

vrothberg on 7 Feb 2020

❤1

Wonderful! We could kinda improve the error message!

Anyway this is very interesting for us!

siscia on 7 Feb 2020

Wonderful! We could kinda improve the error message!

Glad that it's working for you!

vrothberg on 7 Feb 2020

please do not remove --rootfs, It is because of it I changed from docker and nspawn² to podman.

here is a quick guide if needed for new comers:
create an OS

debootstrap --arch=amd64 --include=dbus,apt-transport-https,wget,curl,locales,tzdata,man-db,manpages,dialog,procps,sudo,nano,ifupdown,iproute2,apt-utils,less --components=main,contrib,non-free buster /busterr http://deb.debian.org/debian

change/create the root password:

podman run --rm -it  --rootfs /busterr bash -c "echo 'root:bbbbbbnn' | chpasswd"

run a full OS with systemd (like a vm):

podman run --rm -it --systemd=always --rootfs /busterr /sbin/init

² nspawn was slow compared to podman , podman is as quick as docker (using privileged containers). I could not make nspawn do some funcions in python as quick as podman/docker