EDIT : workaround : sudo dnf install -y policycoreutils-python-utils && sudo semanage permissive -a iptables_t

---

Description

Rootless mode doesn’t start on Fedora 32 with SELinux enabled. It works when SELinux is disabled.

(NOTE: “SELinux enabled” in this context just means getenforce = Enforcing, with the system_u:object_r:container_runtime_exec_t:s0 context for running dockerd. This issue is NOT about running dockerd-rootless.sh with --selinux-enabled)

Steps to reproduce the issue:

1. Set up Fedora 32
2. Download moby-snapshot-fedora-32-x86_64-rpm.tbz from https://github.com/AkihiroSuda/moby-snapshot/releases/tag/snapshot-20200717
3. tar xjvf moby-snapshot-fedora-32-x86_64-rpm.tbz
4. sudo dnf install -y *.rpm 5 . dockerd-rootless.sh

Describe the results you received:

[vagrant@localhost ~]$ dockerd-rootless.sh 
+ '[' -w /run/user/1000 ']'
+ '[' -w /home/vagrant ']'
+ rootlesskit=
+ for f in docker-rootlesskit rootlesskit
+ which docker-rootlesskit
+ for f in docker-rootlesskit rootlesskit
+ which rootlesskit
+ rootlesskit=rootlesskit
+ break
+ '[' -z rootlesskit ']'
+ : ''
+ : ''
+ : builtin
+ : auto
+ : auto
+ net=
+ mtu=
+ '[' -z ']'
+ which slirp4netns
+ slirp4netns --help
+ grep -qw -- --netns-type
+ net=slirp4netns
+ '[' -z ']'
+ mtu=65520
+ '[' -z slirp4netns ']'
+ '[' -z 65520 ']'
+ '[' -z ']'
+ _DOCKERD_ROOTLESS_CHILD=1
+ export _DOCKERD_ROOTLESS_CHILD
+ exec rootlesskit --net=slirp4netns --mtu=65520 --slirp4netns-sandbox=auto --slirp4netns-seccomp=auto --disable-host-loopback --port-driver=builtin --copy-up=/etc --copy-up=/run --propagation=rslave /usr/bin/dockerd-rootless.sh
+ '[' -w /run/user/1000 ']'
+ '[' -w /home/vagrant ']'
+ rootlesskit=
+ for f in docker-rootlesskit rootlesskit
+ which docker-rootlesskit
+ for f in docker-rootlesskit rootlesskit
+ which rootlesskit
+ rootlesskit=rootlesskit
+ break
+ '[' -z rootlesskit ']'
+ : ''
+ : ''
+ : builtin
+ : auto
+ : auto
+ net=
+ mtu=
+ '[' -z ']'
+ which slirp4netns
+ slirp4netns --help
+ grep -qw -- --netns-type
+ net=slirp4netns
+ '[' -z ']'
+ mtu=65520
+ '[' -z slirp4netns ']'
+ '[' -z 65520 ']'
+ '[' -z 1 ']'
+ '[' 1 = 1 ']'
+ rm -f /run/docker /run/xtables.lock
+ exec dockerd
INFO[2020-07-18T02:51:29.598987874Z] Starting up                                  
WARN[2020-07-18T02:51:29.599044054Z] Running in rootless mode. This mode has feature limitations. 
INFO[2020-07-18T02:51:29.599049153Z] Running with RootlessKit integration         
INFO[2020-07-18T02:51:29.600299588Z] libcontainerd: started new containerd process  pid=9337
INFO[2020-07-18T02:51:29.600571807Z] parsed scheme: "unix"                         module=grpc
INFO[2020-07-18T02:51:29.600703491Z] scheme "unix" not registered, fallback to default scheme  module=grpc
INFO[2020-07-18T02:51:29.600829684Z] ccResolverWrapper: sending update to cc: {[{unix:///run/user/1000/docker/containerd/containerd.sock  <nil> 0 <nil>}] <nil> <nil>}  module=grpc
INFO[2020-07-18T02:51:29.600998464Z] ClientConn switching balancer to "pick_first"  module=grpc
INFO[2020-07-18T02:51:29.618626058Z] starting containerd                           revision=4feb8c462393ce6834dda9e3464c4fee8ee73232 version="0.20200717.014906~4feb8c4"
INFO[2020-07-18T02:51:29.638162035Z] loading plugin "io.containerd.content.v1.content"...  type=io.containerd.content.v1
INFO[2020-07-18T02:51:29.638216642Z] loading plugin "io.containerd.snapshotter.v1.aufs"...  type=io.containerd.snapshotter.v1
INFO[2020-07-18T02:51:29.639887838Z] skip loading plugin "io.containerd.snapshotter.v1.aufs"...  error="aufs is not supported (modprobe aufs failed: exit status 1 \"modprobe: FATAL: Module aufs not found in directory /lib/modules/5.6.6-300.fc32.x86_64\\n\"): skip plugin" type=io.containerd.snapshotter.v1
INFO[2020-07-18T02:51:29.639969108Z] loading plugin "io.containerd.snapshotter.v1.devmapper"...  type=io.containerd.snapshotter.v1
WARN[2020-07-18T02:51:29.640017186Z] failed to load plugin io.containerd.snapshotter.v1.devmapper  error="devmapper not configured"
INFO[2020-07-18T02:51:29.640032709Z] loading plugin "io.containerd.snapshotter.v1.native"...  type=io.containerd.snapshotter.v1
INFO[2020-07-18T02:51:29.640056787Z] loading plugin "io.containerd.snapshotter.v1.overlayfs"...  type=io.containerd.snapshotter.v1
INFO[2020-07-18T02:51:29.640128945Z] loading plugin "io.containerd.snapshotter.v1.zfs"...  type=io.containerd.snapshotter.v1
INFO[2020-07-18T02:51:29.640252839Z] skip loading plugin "io.containerd.snapshotter.v1.zfs"...  error="path /home/vagrant/.local/share/docker/containerd/daemon/io.containerd.snapshotter.v1.zfs must be a zfs filesystem to be used with the zfs snapshotter: skip plugin" type=io.containerd.snapshotter.v1
INFO[2020-07-18T02:51:29.640268957Z] loading plugin "io.containerd.metadata.v1.bolt"...  type=io.containerd.metadata.v1
WARN[2020-07-18T02:51:29.640284172Z] could not use snapshotter devmapper in metadata plugin  error="devmapper not configured"
INFO[2020-07-18T02:51:29.640291902Z] metadata content store policy set             policy=shared
INFO[2020-07-18T02:51:29.640441355Z] loading plugin "io.containerd.differ.v1.walking"...  type=io.containerd.differ.v1
INFO[2020-07-18T02:51:29.640672100Z] loading plugin "io.containerd.gc.v1.scheduler"...  type=io.containerd.gc.v1
INFO[2020-07-18T02:51:29.640856727Z] loading plugin "io.containerd.service.v1.introspection-service"...  type=io.containerd.service.v1
INFO[2020-07-18T02:51:29.640884286Z] loading plugin "io.containerd.service.v1.containers-service"...  type=io.containerd.service.v1
INFO[2020-07-18T02:51:29.640894221Z] loading plugin "io.containerd.service.v1.content-service"...  type=io.containerd.service.v1
INFO[2020-07-18T02:51:29.640906814Z] loading plugin "io.containerd.service.v1.diff-service"...  type=io.containerd.service.v1
INFO[2020-07-18T02:51:29.640916268Z] loading plugin "io.containerd.service.v1.images-service"...  type=io.containerd.service.v1
INFO[2020-07-18T02:51:29.640928865Z] loading plugin "io.containerd.service.v1.leases-service"...  type=io.containerd.service.v1
INFO[2020-07-18T02:51:29.640938611Z] loading plugin "io.containerd.service.v1.namespaces-service"...  type=io.containerd.service.v1
INFO[2020-07-18T02:51:29.640950067Z] loading plugin "io.containerd.service.v1.snapshots-service"...  type=io.containerd.service.v1
INFO[2020-07-18T02:51:29.640972084Z] loading plugin "io.containerd.runtime.v1.linux"...  type=io.containerd.runtime.v1
INFO[2020-07-18T02:51:29.641032736Z] loading plugin "io.containerd.runtime.v2.task"...  type=io.containerd.runtime.v2
INFO[2020-07-18T02:51:29.641104258Z] loading plugin "io.containerd.monitor.v1.cgroups"...  type=io.containerd.monitor.v1
INFO[2020-07-18T02:51:29.641486265Z] loading plugin "io.containerd.service.v1.tasks-service"...  type=io.containerd.service.v1
INFO[2020-07-18T02:51:29.641536295Z] loading plugin "io.containerd.internal.v1.restart"...  type=io.containerd.internal.v1
INFO[2020-07-18T02:51:29.641599367Z] loading plugin "io.containerd.grpc.v1.containers"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641619825Z] loading plugin "io.containerd.grpc.v1.content"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641634736Z] loading plugin "io.containerd.grpc.v1.diff"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641643317Z] loading plugin "io.containerd.grpc.v1.events"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641657485Z] loading plugin "io.containerd.grpc.v1.healthcheck"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641686643Z] loading plugin "io.containerd.grpc.v1.images"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641697750Z] loading plugin "io.containerd.grpc.v1.leases"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641709417Z] loading plugin "io.containerd.grpc.v1.namespaces"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641717946Z] loading plugin "io.containerd.internal.v1.opt"...  type=io.containerd.internal.v1
INFO[2020-07-18T02:51:29.641744782Z] loading plugin "io.containerd.grpc.v1.snapshots"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641755111Z] loading plugin "io.containerd.grpc.v1.tasks"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641764533Z] loading plugin "io.containerd.grpc.v1.version"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.641778388Z] loading plugin "io.containerd.grpc.v1.introspection"...  type=io.containerd.grpc.v1
INFO[2020-07-18T02:51:29.642519423Z] serving...                                    address=/run/user/1000/docker/containerd/containerd-debug.sock
INFO[2020-07-18T02:51:29.642649591Z] serving...                                    address=/run/user/1000/docker/containerd/containerd.sock.ttrpc
INFO[2020-07-18T02:51:29.642724411Z] serving...                                    address=/run/user/1000/docker/containerd/containerd.sock
INFO[2020-07-18T02:51:29.642740391Z] containerd successfully booted in 0.024729s  
INFO[2020-07-18T02:51:29.648118109Z] parsed scheme: "unix"                         module=grpc
INFO[2020-07-18T02:51:29.648142231Z] scheme "unix" not registered, fallback to default scheme  module=grpc
INFO[2020-07-18T02:51:29.648157728Z] ccResolverWrapper: sending update to cc: {[{unix:///run/user/1000/docker/containerd/containerd.sock  <nil> 0 <nil>}] <nil> <nil>}  module=grpc
INFO[2020-07-18T02:51:29.648165737Z] ClientConn switching balancer to "pick_first"  module=grpc
INFO[2020-07-18T02:51:29.649079074Z] parsed scheme: "unix"                         module=grpc
INFO[2020-07-18T02:51:29.649142022Z] scheme "unix" not registered, fallback to default scheme  module=grpc
INFO[2020-07-18T02:51:29.649156372Z] ccResolverWrapper: sending update to cc: {[{unix:///run/user/1000/docker/containerd/containerd.sock  <nil> 0 <nil>}] <nil> <nil>}  module=grpc
INFO[2020-07-18T02:51:29.649161973Z] ClientConn switching balancer to "pick_first"  module=grpc
INFO[2020-07-18T02:51:29.649994007Z] [graphdriver] using prior storage driver: fuse-overlayfs 
WARN[2020-07-18T02:51:29.652815432Z] Unable to find cpu controller                
WARN[2020-07-18T02:51:29.653025241Z] Unable to find io controller                 
WARN[2020-07-18T02:51:29.653155342Z] Unable to find cpuset controller             
INFO[2020-07-18T02:51:29.653690214Z] Loading containers: start.                   
WARN[2020-07-18T02:51:29.655152150Z] Running iptables --wait -t nat -L -n failed with message: `Fatal: can't open lock file /run/xtables.lock: Permission denied`, error: exit status 4 
INFO[2020-07-18T02:51:29.672504396Z] stopping event stream following graceful shutdown  error="context canceled" module=libcontainerd namespace=plugins.moby
INFO[2020-07-18T02:51:29.672563671Z] stopping healthcheck following graceful shutdown  module=libcontainerd
INFO[2020-07-18T02:51:29.672613758Z] stopping event stream following graceful shutdown  error="context canceled" module=libcontainerd namespace=moby
failed to start daemon: Error initializing network controller: error obtaining controller instance: failed to create NAT chain DOCKER: iptables failed: iptables -t nat -N DOCKER: Fatal: can't open lock file /run/xtables.lock: Permission denied
 (exit status 4)
[rootlesskit:child ] error: command [/usr/bin/dockerd-rootless.sh] exited: exit status 1
[rootlesskit:parent] error: child exited: exit status 1

Describe the results you expected:

It should work

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

It works by allowing iptables_t to do everything (sudo semanage permissive -a iptables_t) or by just disabling SELinux (sudo setenforce 0).

dockerd-rootless.sh --iptables=false also works. (But not really useful.)

Output of docker version:

$ DOCKER_HOST=unix:///run/user/1000/docker.sock docker version
Client: Moby Engine
 Version:           0.0.0-20200716165816-bece8cc41c
 API version:       1.41
 Go version:        go1.13.10
 Git commit:        bece8cc41c
 Built:             Fri Jul 17 07:07:23 2020
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      false

Server: Moby Engine
 Engine:
  Version:          0.0.0-20200716165816-bece8cc41c
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.13.10
  Git commit:       260c26b7be
  Built:            Fri Jul 17 08:29:21 2020
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          0.20200717.014906~4feb8c4
  GitCommit:        4feb8c462393ce6834dda9e3464c4fee8ee73232
 runc:
  Version:          1.0.0-rc91+dev
  GitCommit:        f9850afa9153b48b654b5c901ae20cabaa4089f8
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683

Output of docker info:

$ DOCKER_HOST=unix:///run/user/1000/docker.sock docker info
Client:
 Context:    default
 Debug Mode: false

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 1
 Server Version: 0.0.0-20200716165816-bece8cc41c
 Storage Driver: fuse-overlayfs
 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 logentries splunk syslog
 Swarm: inactive
 Runtimes: runc io.containerd.runc.v2 io.containerd.runtime.v1.linux
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 4feb8c462393ce6834dda9e3464c4fee8ee73232
 runc version: f9850afa9153b48b654b5c901ae20cabaa4089f8
 init version: fec3683
 Security Options:
  seccomp
   Profile: default
  rootless
  cgroupns
 Kernel Version: 5.6.6-300.fc32.x86_64
 Operating System: Fedora 32 (Cloud Edition)
 OSType: linux
 Architecture: x86_64
 CPUs: 2
 Total Memory: 1.933GiB
 Name: localhost.localdomain
 ID: RKTZ:KLY6:LPTN:TXJ2:3LWP:6YBW:KXQX:XSMG:OO7V:JXR5:TDM7:ZHNN
 Docker Root Dir: /home/vagrant/.local/share/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: No kernel memory limit support
WARNING: No kernel memory TCP limit support
WARNING: No oom kill disable support
WARNING: No cpu cfs quota support
WARNING: No cpu cfs period support
WARNING: No cpu shares support
WARNING: No cpuset support
WARNING: Support for cgroup v2 is experimental
WARNING: No blkio weight support
WARNING: No blkio weight_device support
WARNING: No blkio throttle.read_bps_device support
WARNING: No blkio throttle.write_bps_device support
WARNING: No blkio throttle.read_iops_device support
WARNING: No blkio throttle.write_iops_device support

Additional environment details (AWS, VirtualBox, physical, etc.): container-selinux-2.132.0-1.fc32.noarch kernel-core-5.6.6-300.fc32.x86_64