Hi,
I’m pretty new to docker and was trying to install it and run the hello-world container on a new Ubuntu 25.10 machine.
I followed the steps listed here: Ubuntu | Docker Docs and used the “apt” install method (I am not using docker desktop). Here is the result of docker --version and uname -a as I’m writing this post:
$ docker --version
Docker version 29.1.5, build 0e6fee6
$ uname -a
Linux desktop 6.17.0-8-generic #8-Ubuntu SMP PREEMPT_DYNAMIC Fri Nov 14 21:44:46 UTC 2025 x86_64 GNU/Linux
Everything went well, and the docker system service is running:
sudo systemctl status docker
● docker.service - Docker Application Container Engine
Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; preset: enabled)
Active: active (running) since Sun 2026-01-18 10:47:09 CET; 2h 7min ago
Invocation: a4de63628ab54215a43cfc6be6709c29
TriggeredBy: ● docker.socket
Docs: https://docs.docker.com
Main PID: 10158 (dockerd)
Tasks: 23
Memory: 45.1M (peak: 190.8M)
CPU: 24.629s
CGroup: /system.slice/docker.service
└─10158 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
Jan 18 12:47:06 desktop dockerd[10158]: time="2026-01-18T12:47:06.439408084+01:00" level=error msg="copy stream failed" error="reading from a closed fifo" stream=stdout
Jan 18 12:47:06 desktop dockerd[10158]: time="2026-01-18T12:47:06.439464771+01:00" level=error msg="copy stream failed" error="reading from a closed fifo" stream=stderr
I then tried to run the test container as root (so it is not the classic user-not-in-docker-group error) and got this error:
$ sudo su -
$ docker run hello-world
.............
.............
docker: Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: unable to start init: fork/exec /proc/self/fd/6: permission denied
Run 'docker run --help' for more information
And in /etc/syslog:
2026-01-18T12:50:11.864759+01:00 desktop systemd[1]: tmp-containerd\x2dmount1436078743.mount: Deactivated successfully.
2026-01-18T12:50:11.957393+01:00 desktop containerd[9841]: time="2026-01-18T12:50:11.956529707+01:00" level=info msg="connecting to shim 90a229c2b094a3417ca4f54184b7f965d736f68cc34c5308af9f49ae1f6c8265" address="unix:///run/containerd/s/c2708cbe956af7ef60d9dca64cf58fb52c8fa4ff6f4ecaac3155caaf0ee70a6a" namespace=moby protocol=ttrpc version=3
2026-01-18T12:50:11.978506+01:00 desktop containerd[9841]: time="2026-01-18T12:50:11.978455477+01:00" level=error msg="failed to delete task" error="rpc error: code = NotFound desc = container not created: not found" id=90a229c2b094a3417ca4f54184b7f965d736f68cc34c5308af9f49ae1f6c8265
2026-01-18T12:50:11.978633+01:00 desktop containerd[9841]: time="2026-01-18T12:50:11.978611768+01:00" level=info msg="shim disconnected" id=90a229c2b094a3417ca4f54184b7f965d736f68cc34c5308af9f49ae1f6c8265 namespace=moby
2026-01-18T12:50:11.978675+01:00 desktop containerd[9841]: time="2026-01-18T12:50:11.978626621+01:00" level=info msg="cleaning up after shim disconnected" id=90a229c2b094a3417ca4f54184b7f965d736f68cc34c5308af9f49ae1f6c8265 namespace=moby
2026-01-18T12:50:11.978690+01:00 desktop containerd[9841]: time="2026-01-18T12:50:11.978632468+01:00" level=info msg="cleaning up dead shim" id=90a229c2b094a3417ca4f54184b7f965d736f68cc34c5308af9f49ae1f6c8265 namespace=moby
2026-01-18T12:50:11.983515+01:00 desktop containerd[9841]: time="2026-01-18T12:50:11.983462014+01:00" level=warning msg="warnings while cleaning up dead shim" id=90a229c2b094a3417ca4f54184b7f965d736f68cc34c5308af9f49ae1f6c8265 namespace=moby warnings="time=\"2026-01-18T12:50:11+01:00\" level=warning msg=\"failed to read init pid file\" error=\"open /run/containerd/io.containerd.runtime.v2.task/moby/90a229c2b094a3417ca4f54184b7f965d736f68cc34c5308af9f49ae1f6c8265/init.pid: no such file or directory\" runtime=io.containerd.runc.v2\n"
2026-01-18T12:50:11.983729+01:00 desktop containerd[9841]: time="2026-01-18T12:50:11.983711227+01:00" level=error msg="copy shim log" error="read /proc/self/fd/13: file already closed" namespace=moby
2026-01-18T12:50:11.984242+01:00 desktop dockerd[10158]: time="2026-01-18T12:50:11.984035219+01:00" level=error msg="copy stream failed" error="reading from a closed fifo" stream=stdout
2026-01-18T12:50:11.984322+01:00 desktop dockerd[10158]: time="2026-01-18T12:50:11.984033264+01:00" level=error msg="copy stream failed" error="reading from a closed fifo" stream=stderr
2026-01-18T12:50:12.856456+01:00 desktop systemd[1]: var-lib-docker-rootfs-overlayfs-90a229c2b094a3417ca4f54184b7f965d736f68cc34c5308af9f49ae1f6c8265.mount: Deactivated successfully.
It seems docker is unable to create a fd in /proc/self, but I can’t figure out why. I get the exact same error when running another container I need to work with, so this i not limited to the test container.
I have apparmor installed, but it is not an apparmor error, as:
- there is no auditd log related to docker;
systemctl stop apparmordoes not change the outcome;docker run --security-opt seccomp=unconfined --security-opt apparmor=unconfined hello-worldgives the same output
Using strace (I’m even newer to strace than docker), I found these lines that might correspond to my problem:
$ sudo strace docker run hello-world
..............
readlinkat(AT_FDCWD, "/proc/self/exe", "/usr/bin/docker", 128) = 15
openat(AT_FDCWD, "/usr/bin/docker", O_RDONLY|O_CLOEXEC) = 3
fcntl(3, F_GETFL) = 0x8000 (flags O_RDONLY|O_LARGEFILE)
fcntl(3, F_SETFL, O_RDONLY|O_NONBLOCK|O_LARGEFILE) = 0
epoll_create1(EPOLL_CLOEXEC) = 4
eventfd2(0, EFD_CLOEXEC|EFD_NONBLOCK) = 5
epoll_ctl(4, EPOLL_CTL_ADD, 5, {events=EPOLLIN, data=0x614ae0ee30a8}) = 0
epoll_ctl(4, EPOLL_CTL_ADD, 3, {events=EPOLLIN|EPOLLOUT|EPOLLRDHUP|EPOLLET, data=0x3d81328247000001}) = -1 EPERM (Operation not permitted)
..............
But i have no clue what to do with that information, or even if it’s relevant to my problem.
If anyone could show me what I did wrong, i would be grateful.
EDIT:
By uninstalling every docker-related packages and installing Docker Desktop, everything works fine.
This is not ideal and I would still love to understand what the problem is, but I can work with that.