Description
I don't think this is actually a bug, on many respects it is an improvement. But it introduces silent changes that may break some workflows (talking from experience).
With v29 also containerd 2.1.5 was released (previously I had 1.7). It is installed with different ulimit settings for the allowed number of open files (see containerd/containerd@3ca39ef).
This is inherited down the way and changes the default settings of running containers.
Reproduce
Tested on ubuntu 24.
- Usual docker installation procedure, but pin containerd.io:
sudo apt install docker-ce docker-ce-cli **containerd.io=1.7.29-1~ubuntu.24.04~noble** docker-buildx-plugin docker-compose-plugin -y
sudo docker run ubuntu bash -c 'ulimit -n' returns 1048576 (the number may be different depending on th host)sudo apt install containerd.io=2.1.5-1~ubuntu.24.04~noblesudo docker run ubuntu bash -c 'ulimit -n' returns 1024
Expected behavior
No response
docker version
Client: Docker Engine - Community
Version: 29.0.0
API version: 1.52
Go version: go1.25.4
Git commit: 3d4129b
Built: Mon Nov 10 21:46:31 2025
OS/Arch: linux/amd64
Context: default
Server: Docker Engine - Community
Engine:
Version: 29.0.0
API version: 1.52 (minimum version 1.44)
Go version: go1.25.4
Git commit: d105562
Built: Mon Nov 10 21:46:31 2025
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: v2.1.5
GitCommit: fcd43222d6b07379a4be9786bda52438f0dd16a1
runc:
Version: 1.2.5
GitCommit: v1.2.5-0-g59923ef1
docker-init:
Version: 0.19.0
GitCommit: de40ad0
docker info
Client: Docker Engine - Community
Version: 29.0.0
Context: default
Debug Mode: false
Plugins:
buildx: Docker Buildx (Docker Inc.)
Version: v0.29.1
Path: /usr/libexec/docker/cli-plugins/docker-buildx
compose: Docker Compose (Docker Inc.)
Version: v2.40.3
Path: /usr/libexec/docker/cli-plugins/docker-compose
Server:
Containers: 2
Running: 0
Paused: 0
Stopped: 2
Images: 1
Server Version: 29.0.0
Storage Driver: overlayfs
driver-type: io.containerd.snapshotter.v1
Logging Driver: json-file
Cgroup Driver: systemd
Cgroup Version: 2
Plugins:
Volume: local
Network: bridge host ipvlan macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
CDI spec directories:
/etc/cdi
/var/run/cdi
Swarm: inactive
Runtimes: io.containerd.runc.v2 runc
Default Runtime: runc
Init Binary: docker-init
containerd version: fcd43222d6b07379a4be9786bda52438f0dd16a1
runc version: v1.3.3-0-gd842d771
init version: de40ad0
Security Options:
apparmor
seccomp
Profile: builtin
cgroupns
Kernel Version: 6.14.0-1015-aws
Operating System: Ubuntu 24.04.3 LTS
OSType: linux
Architecture: x86_64
CPUs: 16
Total Memory: 40.24GiB
Name: doc
ID: 842c7ac8-17f3-49d4-8807-249e8a1fc755
Docker Root Dir: /var/lib/docker
Debug Mode: false
Experimental: false
Insecure Registries:
::1/128
127.0.0.0/8
Live Restore Enabled: false
Firewall Backend: iptablesAdditional Info
No response
Description
I don't think this is actually a bug, on many respects it is an improvement. But it introduces silent changes that may break some workflows (talking from experience).
With v29 also containerd 2.1.5 was released (previously I had 1.7). It is installed with different ulimit settings for the allowed number of open files (see containerd/containerd@3ca39ef).
This is inherited down the way and changes the default settings of running containers.
Reproduce
Tested on ubuntu 24.
sudo apt install docker-ce docker-ce-cli **containerd.io=1.7.29-1~ubuntu.24.04~noble** docker-buildx-plugin docker-compose-plugin -ysudo docker run ubuntu bash -c 'ulimit -n'returns 1048576 (the number may be different depending on th host)sudo apt install containerd.io=2.1.5-1~ubuntu.24.04~noblesudo docker run ubuntu bash -c 'ulimit -n'returns 1024Expected behavior
No response
docker version
Client: Docker Engine - Community Version: 29.0.0 API version: 1.52 Go version: go1.25.4 Git commit: 3d4129b Built: Mon Nov 10 21:46:31 2025 OS/Arch: linux/amd64 Context: default Server: Docker Engine - Community Engine: Version: 29.0.0 API version: 1.52 (minimum version 1.44) Go version: go1.25.4 Git commit: d105562 Built: Mon Nov 10 21:46:31 2025 OS/Arch: linux/amd64 Experimental: false containerd: Version: v2.1.5 GitCommit: fcd43222d6b07379a4be9786bda52438f0dd16a1 runc: Version: 1.2.5 GitCommit: v1.2.5-0-g59923ef1 docker-init: Version: 0.19.0 GitCommit: de40ad0docker info
Additional Info
No response