Error creating cgroup directory

[GolanTrevize10]

Description

I am running rootful podman in a non-privileged container in Kubernetes. If I try to run a container with podman it works correctly, but when I try to build an image I get this error

sh-4.4# podman build . -t test
STEP 1/2: FROM ubi8
STEP 2/2: RUN echo hello
error running container: error from /usr/bin/crun creating container for [/bin/sh -c echo hello]: creating cgroup directory `/sys/fs/cgroup/pids/buildah-buildah2937778511`: No such file or directory
: exit status 1
Error: error building at STEP "RUN echo hello": error while running runtime: exit status 1

I suspect it has something to do with apparmor, but I cannot see anything in our apparmor profile

Output of rpm -q podman :

podman-4.2.0-6.module+el8.7.0+17498+a7f63b89.x86_64

Output of podman version:

Client:       Podman Engine
Version:      4.2.0
API Version:  4.2.0
Go Version:   go1.18.4
Built:        Mon Dec 12 11:41:56 2022
OS/Arch:      linux/amd64

*Output of `cat /etc/release`:**

NAME="Red Hat Enterprise Linux"
VERSION="8.7 (Ootpa)"
ID="rhel"
ID_LIKE="fedora"
VERSION_ID="8.7"
PLATFORM_ID="platform:el8"
PRETTY_NAME="Red Hat Enterprise Linux 8.7 (Ootpa)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:redhat:enterprise_linux:8::baseos"
HOME_URL="https://www.redhat.com/"
DOCUMENTATION_URL="https://access.redhat.com/documentation/red_hat_enterprise_linux/8/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"

REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 8"
REDHAT_BUGZILLA_PRODUCT_VERSION=8.7
REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
REDHAT_SUPPORT_PRODUCT_VERSION="8.7"
Red Hat Enterprise Linux release 8.7 (Ootpa)
Red Hat Enterprise Linux release 8.7 (Ootpa)

Output of uname -a:

Linux no-priv-rootful 5.4.0-1094-azure #100~18.04.1-Ubuntu SMP Mon Oct 17 11:44:30 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

Output of cat /etc/containers/storage.conf:

Linux no-priv-rootful 5.4.0-1094-azure #100~18.04.1-Ubuntu SMP Mon Oct 17 11:44:30 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
sh-4.4# cat /etc/containers/storage.conf
# This file is is the configuration file for all tools
# that use the containers/storage library. The storage.conf file
# overrides all other storage.conf files. Container engines using the
# container/storage library do not inherit fields from other storage.conf
# files.
#
#  Note: The storage.conf file overrides other storage.conf files based on this precedence:
#      /usr/containers/storage.conf
#      /etc/containers/storage.conf
#      $HOME/.config/containers/storage.conf
#      $XDG_CONFIG_HOME/containers/storage.conf (If XDG_CONFIG_HOME is set)
# See man 5 containers-storage.conf for more information
# The "container storage" table contains all of the server options.
[storage]

# Default Storage Driver, Must be set for proper operation.
driver = "overlay"

# Temporary storage location
runroot = "/run/containers/storage"

# Primary Read/Write location of container storage
# When changing the graphroot location on an SELINUX system, you must
# ensure  the labeling matches the default locations labels with the
# following commands:
# semanage fcontext -a -e /var/lib/containers/storage /NEWSTORAGEPATH
# restorecon -R -v /NEWSTORAGEPATH
graphroot = "/var/lib/containers/storage"

# Storage path for rootless users
#
# rootless_storage_path = "$HOME/.local/share/containers/storage"

[storage.options]
# Storage options to be passed to underlying storage drivers

# AdditionalImageStores is used to pass paths to additional Read/Only image stores
# Must be comma separated list.
additionalimagestores = [
]

# Allows specification of how storage is populated when pulling images. This
# option can speed the pulling process of images compressed with format
# zstd:chunked. Containers/storage looks for files within images that are being
# pulled from a container registry that were previously pulled to the host.  It
# can copy or create a hard link to the existing file when it finds them,
# eliminating the need to pull them from the container registry. These options
# can deduplicate pulling of content, disk storage of content and can allow the
# kernel to use less memory when running containers.

# containers/storage supports four keys
#   * enable_partial_images="true" | "false"
#     Tells containers/storage to look for files previously pulled in storage
#     rather then always pulling them from the container registry.
#   * use_hard_links = "false" | "true"
#     Tells containers/storage to use hard links rather then create new files in
#     the image, if an identical file already existed in storage.
#   * ostree_repos = ""
#     Tells containers/storage where an ostree repository exists that might have
#     previously pulled content which can be used when attempting to avoid
#     pulling content from the container registry
pull_options = {enable_partial_images = "false", use_hard_links = "false", ostree_repos=""}

# Remap-UIDs/GIDs is the mapping from UIDs/GIDs as they should appear inside of
# a container, to the UIDs/GIDs as they should appear outside of the container,
# and the length of the range of UIDs/GIDs.  Additional mapped sets can be
# listed and will be heeded by libraries, but there are limits to the number of
# mappings which the kernel will allow when you later attempt to run a
# container.
#
# remap-uids = 0:1668442479:65536
# remap-gids = 0:1668442479:65536

# Remap-User/Group is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid or /etc/subgid file.  Mappings are set up starting
# with an in-container ID of 0 and then a host-level ID taken from the lowest
# range that matches the specified name, and using the length of that range.
# Additional ranges are then assigned, using the ranges which specify the
# lowest host-level IDs first, to the lowest not-yet-mapped in-container ID,
# until all of the entries have been used for maps.
#
# remap-user = "containers"
# remap-group = "containers"

# Root-auto-userns-user is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid and /etc/subgid file.  These ranges will be partitioned
# to containers configured to create automatically a user namespace.  Containers
# configured to automatically create a user namespace can still overlap with containers
# having an explicit mapping set.
# This setting is ignored when running as rootless.
# root-auto-userns-user = "storage"
#
# Auto-userns-min-size is the minimum size for a user namespace created automatically.
# auto-userns-min-size=1024
#
# Auto-userns-max-size is the minimum size for a user namespace created automatically.
# auto-userns-max-size=65536

[storage.options.overlay]
# ignore_chown_errors can be set to allow a non privileged user running with
# a single UID within a user namespace to run containers. The user can pull
# and use any image even those with multiple uids.  Note multiple UIDs will be
# squashed down to the default uid in the container.  These images will have no
# separation between the users in the container. Only supported for the overlay
# and vfs drivers.
#ignore_chown_errors = "false"

# Inodes is used to set a maximum inodes of the container image.
# inodes = ""

# Path to an helper program to use for mounting the file system instead of mounting it
# directly.
#mount_program = "/usr/bin/fuse-overlayfs"

# mountopt specifies comma separated list of extra mount options
mountopt = "nodev,metacopy=on"

# Set to skip a PRIVATE bind mount on the storage home directory.
# skip_mount_home = "false"

# Size is used to set a maximum size of the container image.
# size = ""

# ForceMask specifies the permissions mask that is used for new files and
# directories.
#
# The values "shared" and "private" are accepted.
# Octal permission masks are also accepted.
#
#  "": No value specified.
#     All files/directories, get set with the permissions identified within the
#     image.
#  "private": it is equivalent to 0700.
#     All files/directories get set with 0700 permissions.  The owner has rwx
#     access to the files. No other users on the system can access the files.
#     This setting could be used with networked based homedirs.
#  "shared": it is equivalent to 0755.
#     The owner has rwx access to the files and everyone else can read, access
#     and execute them. This setting is useful for sharing containers storage
#     with other users.  For instance have a storage owned by root but shared
#     to rootless users as an additional store.
#     NOTE:  All files within the image are made readable and executable by any
#     user on the system. Even /etc/shadow within your image is now readable by
#     any user.
#
#   OCTAL: Users can experiment with other OCTAL Permissions.
#
#  Note: The force_mask Flag is an experimental feature, it could change in the
#  future.  When "force_mask" is set the original permission mask is stored in
#  the "user.containers.override_stat" xattr and the "mount_program" option must
#  be specified. Mount programs like "/usr/bin/fuse-overlayfs" present the
#  extended attribute permissions to processes within containers rather then the
#  "force_mask"  permissions.
#
# force_mask = ""

[storage.options.thinpool]
# Storage Options for thinpool

# autoextend_percent determines the amount by which pool needs to be
# grown. This is specified in terms of % of pool size. So a value of 20 means
# that when threshold is hit, pool will be grown by 20% of existing
# pool size.
# autoextend_percent = "20"

# autoextend_threshold determines the pool extension threshold in terms
# of percentage of pool size. For example, if threshold is 60, that means when
# pool is 60% full, threshold has been hit.
# autoextend_threshold = "80"

# basesize specifies the size to use when creating the base device, which
# limits the size of images and containers.
# basesize = "10G"

# blocksize specifies a custom blocksize to use for the thin pool.
# blocksize="64k"

# directlvm_device specifies a custom block storage device to use for the
# thin pool. Required if you setup devicemapper.
# directlvm_device = ""

# directlvm_device_force wipes device even if device already has a filesystem.
# directlvm_device_force = "True"

# fs specifies the filesystem type to use for the base device.
# fs="xfs"

# log_level sets the log level of devicemapper.
# 0: LogLevelSuppress 0 (Default)
# 2: LogLevelFatal
# 3: LogLevelErr
# 4: LogLevelWarn
# 5: LogLevelNotice
# 6: LogLevelInfo
# 7: LogLevelDebug
# log_level = "7"

# min_free_space specifies the min free space percent in a thin pool require for
# new device creation to succeed. Valid values are from 0% - 99%.
# Value 0% disables
# min_free_space = "10%"

# mkfsarg specifies extra mkfs arguments to be used when creating the base
# device.
# mkfsarg = ""

# metadata_size is used to set the `pvcreate --metadatasize` options when
# creating thin devices. Default is 128k
# metadata_size = ""

# Size is used to set a maximum size of the container image.
# size = ""

# use_deferred_removal marks devicemapper block device for deferred removal.
# If the thinpool is in use when the driver attempts to remove it, the driver
# tells the kernel to remove it as soon as possible. Note this does not free
# up the disk space, use deferred deletion to fully remove the thinpool.
# use_deferred_removal = "True"

# use_deferred_deletion marks thinpool device for deferred deletion.
# If the device is busy when the driver attempts to delete it, the driver
# will attempt to delete device every 30 seconds until successful.
# If the program using the driver exits, the driver will continue attempting
# to cleanup the next time the driver is used. Deferred deletion permanently
# deletes the device and all data stored in device will be lost.
# use_deferred_deletion = "True"

# xfs_nospace_max_retries specifies the maximum number of retries XFS should
# attempt to complete IO when ENOSPC (no space) error is returned by
# underlying storage device.
# xfs_nospace_max_retries = "0"

Output of podman info:

host:
  arch: amd64
  buildahVersion: 1.27.3
  cgroupControllers:
  - cpuset
  - cpu
  - cpuacct
  - blkio
  - memory
  - devices
  - freezer
  - net_cls
  - perf_event
  - net_prio
  - hugetlb
  - pids
  - rdma
  cgroupManager: cgroupfs
  cgroupVersion: v1
  conmon:
    package: conmon-2.1.4-1.module+el8.7.0+17498+a7f63b89.x86_64
    path: /usr/bin/conmon
    version: 'conmon version 2.1.4, commit: 419a7c7817d7da098aa7648abddea5014f593ac6'
  cpuUtilization:
    idlePercent: 99.66
    systemPercent: 0.14
    userPercent: 0.2
  cpus: 32
  distribution:
    distribution: '"rhel"'
    version: "8.7"
  eventLogger: file
  hostname: no-priv-rootful
  idMappings:
    gidmap: null
    uidmap: null
  kernel: 5.4.0-1094-azure
  linkmode: dynamic
  logDriver: k8s-file
  memFree: 105784659968
  memTotal: 135184982016
  networkBackend: cni
  ociRuntime:
    name: crun
    package: crun-1.5-1.module+el8.7.0+17498+a7f63b89.x86_64
    path: /usr/bin/crun
    version: |-
      crun version 1.5
      commit: 54ebb8ca8bf7e6ddae2eb919f5b82d1d96863dea
      spec: 1.0.0
      +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +YAJL
  os: linux
  remoteSocket:
    path: /run/podman/podman.sock
  security:
    apparmorEnabled: false
    capabilities: CAP_NET_RAW,CAP_CHOWN,CAP_DAC_OVERRIDE,CAP_FOWNER,CAP_FSETID,CAP_KILL,CAP_NET_BIND_SERVICE,CAP_SETFCAP,CAP_SETGID,CAP_SETPCAP,CAP_SETUID,CAP_SYS_CHROOT
    rootless: false
    seccompEnabled: true
    seccompProfilePath: /usr/share/containers/seccomp.json
    selinuxEnabled: false
  serviceIsRemote: false
  slirp4netns:
    executable: /usr/bin/slirp4netns
    package: slirp4netns-1.2.0-2.module+el8.7.0+17498+a7f63b89.x86_64
    version: |-
      slirp4netns version 1.2.0
      commit: 656041d45cfca7a4176f6b7eed9e4fe6c11e8383
      libslirp: 4.4.0
      SLIRP_CONFIG_VERSION_MAX: 3
      libseccomp: 2.5.2
  swapFree: 0
  swapTotal: 0
  uptime: 1558h 22m 20.00s (Approximately 64.92 days)
plugins:
  authorization: null
  log:
  - k8s-file
  - none
  - passthrough
  - journald
  network:
  - bridge
  - macvlan
  - ipvlan
  volume:
  - local
registries:
  search:
  - registry.access.redhat.com
  - registry.redhat.io
  - docker.io
store:
  configFile: /etc/containers/storage.conf
  containerStore:
    number: 0
    paused: 0
    running: 0
    stopped: 0
  graphDriverName: overlay
  graphOptions:
    overlay.mountopt: nodev,metacopy=on
  graphRoot: /var/lib/containers/storage
  graphRootAllocated: 416055988224
  graphRootUsed: 46537732096
  graphStatus:
    Backing Filesystem: extfs
    Native Overlay Diff: "false"
    Supports d_type: "true"
    Using metacopy: "true"
  imageCopyTmpDir: /var/tmp
  imageStore:
    number: 1
  runRoot: /run/containers/storage
  volumePath: /var/lib/containers/storage/volumes
version:
  APIVersion: 4.2.0
  Built: 1670845316
  BuiltTime: Mon Dec 12 11:41:56 2022
  GitCommit: ""
  GoVersion: go1.18.4
  Os: linux
  OsArch: linux/amd64
  Version: 4.2.0

[rhatdan]

Try to break it down into individual commands.

ctr=$(buildah from ubi8) buildah run $ctr echo hello

[GolanTrevize10]

I am using podman not buildah directly. And I am building a Dockerfile

[rhatdan]

Ok it is a non-privileged container, so you will not work. Please read https://www.redhat.com/sysadmin/podman-inside-kubernetes

[GolanTrevize10]

@rhatdan there is a section in that document you shared explaning how to run podman in a non-privileged container. So it is possible.

After investigating a bit I found out the problem is the cgroup mount in /sys/fs/cgroup/pids is read only. Any idea why?

sh-4.4# mount |grep pids cgroup on /sys/fs/cgroup/pids type cgroup (ro,nosuid,nodev,noexec,relatime,pids)

[rhatdan]

Nope. I am not a k8s expert. @umohnani8 PTAL

[GolanTrevize10]

I found the issue. I was not using isolation chroot