BUG REPORT INFORMATION
I used to run docker containers with systemd as CMD without having to expose /sys/fs/cgroup as rw; this worked until systemd 248 on the host. Now it fails with
Failed to create /init.scope control group: Read-only file system
Failed to allocate manager object: Read-only file system
[!!!!!!] Failed to allocate manager object.
Exiting PID 1...
I opened a related issue on the systemd github repo: systemd/systemd#19245
Workarounds
- boot host with systemd.unified_cgroup_hierarchy=0
- remove ro flag from docker run arg -v /sys/fs/cgroup:/sys/fs/cgroup:ro but this contaminates the host cgroup, causing e.g. docker top to get confused:
docker top debian-systemd
Error response from daemon: runc did not terminate successfully: container_linux.go:186: getting all container pids from cgroups caused: lstat /sys/fs/cgroup/system.slice/docker-817dfec3facbeb10c64d7b0fae478804b1177ae949e695e111b7c693569dd21a.scope: no such file or directory
: unknown
Steps to reproduce the issue:
Dockerfile:
FROM debian:buster-slim
ENV container docker
ENV LC_ALL C
ENV DEBIAN_FRONTEND noninteractive
USER root
WORKDIR /root
RUN set -x
RUN apt-get update -y \
&& apt-get install --no-install-recommends -y systemd \
&& apt-get clean \
&& rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* \
&& rm -f /var/run/nologin
RUN rm -f /lib/systemd/system/multi-user.target.wants/* \
/etc/systemd/system/*.wants/* \
/lib/systemd/system/local-fs.target.wants/* \
/lib/systemd/system/sockets.target.wants/*udev* \
/lib/systemd/system/sockets.target.wants/*initctl* \
/lib/systemd/system/sysinit.target.wants/systemd-tmpfiles-setup* \
/lib/systemd/system/systemd-update-utmp*
VOLUME [ "/sys/fs/cgroup" ]
CMD ["/lib/systemd/systemd"]
Expected behaviour
systemd 247 (247.4-2-arch)
+PAM +AUDIT -SELINUX -IMA -APPARMOR +SMACK -SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +ZSTD +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN +PCRE2 default-hierarchy=hybrid
$ docker build -t debian-systemd .
$ docker run -t --tmpfs /run --tmpfs /run/lock --tmpfs /tmp -v /sys/fs/cgroup:/sys/fs/cgroup:ro debian-systemd
systemd 241 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN -PCRE2 default-hierarchy=hybrid)
Detected virtualization docker.
Detected architecture x86-64.
Welcome to Debian GNU/Linux 10 (buster)!
Set hostname to <bf431002c7c1>.
Couldn't move remaining userspace processes, ignoring: Input/output error
File /lib/systemd/system/systemd-journald.service:12 configures an IP firewall (IPAddressDeny=any), but the local system does not support BPF/cgroup based firewalling.
Proceeding WITHOUT firewalling in effect! (This warning is only shown for the first loaded unit using IP firewalling.)
[ OK ] Listening on Journal Socket.
...
[ OK ] Reached target Graphical Interface.
Actual behaviour
Since systemd v248
$ /lib/systemd/systemd --version
systemd 248 (248-3-arch)
+PAM +AUDIT -SELINUX -APPARMOR -IMA +SMACK +SECCOMP +GCRYPT +GNUTLS +OPENSSL +ACL +BLKID +CURL +ELFUTILS +FIDO2 +IDN2 -IDN +IPTC +KMOD +LIBCRYPTSETUP +LIBFDISK +PCRE2 -PWQUALITY +P11KIT -QRENCODE +BZIP2 +LZ4 +XZ +ZLIB +ZSTD +XKBCOMMON +UTMP -SYSVINIT default-hierarchy=unified
$ docker build -t debian-systemd .
$ docker run -t --tmpfs /run --tmpfs /run/lock --tmpfs /tmp -v /sys/fs/cgroup:/sys/fs/cgroup:ro debian-systemd
systemd 241 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN -PCRE2 default-hierarchy=hybrid)
Detected virtualization docker.
Detected architecture x86-64.
Welcome to Debian GNU/Linux 10 (buster)!
Set hostname to <fbb4fc19cb95>.
Failed to create /init.scope control group: Read-only file system
Failed to allocate manager object: Read-only file system
[!!!!!!] Failed to allocate manager object.
Exiting PID 1...
Output of docker version:
$ docker version
Client:
Version: 20.10.5
API version: 1.41
Go version: go1.16
Git commit: 55c4c88966
Built: Wed Mar 3 16:51:54 2021
OS/Arch: linux/amd64
Context: default
Experimental: true
Server:
Engine:
Version: 20.10.5
API version: 1.41 (minimum version 1.12)
Go version: go1.16
Git commit: 363e9a88a1
Built: Wed Mar 3 16:51:28 2021
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: v1.4.4
GitCommit: 05f951a3781f4f2c1911b05e61c160e9c30eaa8e.m
runc:
Version: 1.0.0-rc93
GitCommit: 12644e614e25b05da6fd08a38ffa0cfe1903fdec
docker-init:
Version: 0.19.0
GitCommit: de40ad0
Output of docker info:
Client:
Context: default
Debug Mode: false
Plugins:
app: Docker App (Docker Inc., v0.9.1-beta3)
buildx: Build with BuildKit (Docker Inc., v0.5.1-tp-docker)
Server:
Containers: 10
Running: 1
Paused: 0
Stopped: 9
Images: 61
Server Version: 20.10.5
Storage Driver: overlay2
Backing Filesystem: extfs
Supports d_type: true
Native Overlay Diff: false
Logging Driver: json-file
Cgroup Driver: cgroupfs
Cgroup Version: 1
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: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 05f951a3781f4f2c1911b05e61c160e9c30eaa8e.m
runc version: 12644e614e25b05da6fd08a38ffa0cfe1903fdec
init version: de40ad0
Security Options:
seccomp
Profile: default
Kernel Version: 5.11.11-arch1-1
Operating System: Arch Linux
OSType: linux
Architecture: x86_64
CPUs: 8
Total Memory: 7.712GiB
Name: homepc
ID: 67YO:62DZ:3NIF:TZT3:HTXP:BU6I:YBR3:XETA:7YCB:YGNN:MV6Q:QYN4
Docker Root Dir: /var/lib/docker
Debug Mode: false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
127.0.0.0/8
Registry Mirrors:
https://mirror.gcr.io/
Live Restore Enabled: false
Additional environment details (AWS, VirtualBox, physical, etc.):
x86_64 Intel hw, Arch Linux 5.11.11-arch1-1
BUG REPORT INFORMATION
I used to run docker containers with systemd as CMD without having to expose /sys/fs/cgroup as rw; this worked until systemd 248 on the host. Now it fails with
I opened a related issue on the systemd github repo: systemd/systemd#19245
Workarounds
Steps to reproduce the issue:
Dockerfile:
Expected behaviour
Actual behaviour
Since systemd v248
Output of
docker version:Output of
docker info:Additional environment details (AWS, VirtualBox, physical, etc.):
x86_64 Intel hw, Arch Linux 5.11.11-arch1-1