Container gets private network when pod is created with --network=host

[mskarbek]

Is this a BUG REPORT or FEATURE REQUEST? (leave only one on its own line)

/kind bug

Description

Steps to reproduce the issue:

1. podman pod create --network=host --name=net-test

2. podman run -d --pod=net-test ubi8/ubi:8.5 sleep 300

Describe the results you received:

# podman inspect 40625a49989e-infra | jq .[].NetworkSettings
{
  "EndpointID": "",
  "Gateway": "",
  "IPAddress": "",
  "IPPrefixLen": 0,
  "IPv6Gateway": "",
  "GlobalIPv6Address": "",
  "GlobalIPv6PrefixLen": 0,
  "MacAddress": "",
  "Bridge": "",
  "SandboxID": "",
  "HairpinMode": false,
  "LinkLocalIPv6Address": "",
  "LinkLocalIPv6PrefixLen": 0,
  "Ports": {},
  "SandboxKey": ""
}
# podman inspect boring_grothendieck | jq .[].NetworkSettings
{
  "EndpointID": "",
  "Gateway": "10.88.0.1",
  "IPAddress": "10.88.0.2",
  "IPPrefixLen": 16,
  "IPv6Gateway": "",
  "GlobalIPv6Address": "",
  "GlobalIPv6PrefixLen": 0,
  "MacAddress": "c6:12:25:1c:c1:bd",
  "Bridge": "",
  "SandboxID": "",
  "HairpinMode": false,
  "LinkLocalIPv6Address": "",
  "LinkLocalIPv6PrefixLen": 0,
  "Ports": {},
  "SandboxKey": "/run/netns/netns-cd354ff6-27b8-c6a7-1c8e-70af40e457bb",
  "Networks": {
    "podman": {
      "EndpointID": "",
      "Gateway": "10.88.0.1",
      "IPAddress": "10.88.0.2",
      "IPPrefixLen": 16,
      "IPv6Gateway": "",
      "GlobalIPv6Address": "",
      "GlobalIPv6PrefixLen": 0,
      "MacAddress": "c6:12:25:1c:c1:bd",
      "NetworkID": "podman",
      "DriverOpts": null,
      "IPAMConfig": null,
      "Links": null,
      "Aliases": [
        "75ac3dca28c4"
      ]
    }
  }
}

Describe the results you expected:
Container should also get host network.

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

Output of podman version:

Client:       Podman Engine
Version:      4.0.0
API Version:  4.0.0
Go Version:   go1.17.7

Built:      Mon Feb 21 21:35:55 2022
OS/Arch:    linux/amd64

Output of podman info --debug:

host:
  arch: amd64
  buildahVersion: 1.24.1
  cgroupControllers:
  - cpuset
  - cpu
  - io
  - memory
  - hugetlb
  - pids
  - rdma
  cgroupManager: systemd
  cgroupVersion: v2
  conmon:
    package: conmon-2.1.0-1.module+el8.6.0+14131+b9baa4cc.x86_64
    path: /usr/bin/conmon
    version: 'conmon version 2.1.0, commit: 69671bb13ee783c4924db64b241139d61db07321'
  cpus: 4
  distribution:
    distribution: '"rhel"'
    version: "8.6"
  eventLogger: journald
  hostname: cn01
  idMappings:
    gidmap: null
    uidmap: null
  kernel: 4.18.0-369.el8.x86_64
  linkmode: dynamic
  logDriver: journald
  memFree: 6740848640
  memTotal: 8232390656
  networkBackend: cni
  ociRuntime:
    name: crun
    package: crun-1.4.2-1.module+el8.6.0+14131+b9baa4cc.x86_64
    path: /usr/bin/crun
    version: |-
      crun version 1.4.2
      commit: f6fbc8f840df1a414f31a60953ae514fa497c748
      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: true
  serviceIsRemote: false
  slirp4netns:
    executable: /bin/slirp4netns
    package: slirp4netns-1.1.8-2.module+el8.6.0+14272+4d6325e6.x86_64
    version: |-
      slirp4netns version 1.1.8
      commit: d361001f495417b880f20329121e3aa431a8f90f
      libslirp: 4.4.0
      SLIRP_CONFIG_VERSION_MAX: 3
      libseccomp: 2.5.2
  swapFree: 0
  swapTotal: 0
  uptime: 1h 36m 15.2s (Approximately 0.04 days)
plugins:
  log:
  - k8s-file
  - none
  - passthrough
  - journald
  network:
  - bridge
  - macvlan
  - ipvlan
  volume:
  - local
registries:
  search:
  - registry.fedoraproject.org
  - registry.access.redhat.com
  - registry.centos.org
  - docker.io
store:
  configFile: /etc/containers/storage.conf
  containerStore:
    number: 3
    paused: 0
    running: 1
    stopped: 2
  graphDriverName: overlay
  graphOptions:
    overlay.mountopt: nodev,metacopy=on
  graphRoot: /var/lib/containers/storage
  graphStatus:
    Backing Filesystem: xfs
    Native Overlay Diff: "false"
    Supports d_type: "true"
    Using metacopy: "true"
  imageCopyTmpDir: /var/tmp
  imageStore:
    number: 5
  runRoot: /run/containers/storage
  volumePath: /var/lib/volumes/storage
version:
  APIVersion: 4.0.0
  Built: 1645479355
  BuiltTime: Mon Feb 21 21:35:55 2022
  GitCommit: ""
  GoVersion: go1.17.7
  OsArch: linux/amd64
  Version: 4.0.0

Package info (e.g. output of rpm -q podman or apt list podman):

podman-4.0.0-3.module+el8.6.0+14305+6b14f34e.x86_64

Have you tested with the latest version of Podman and have you checked the Podman Troubleshooting Guide? (https://github.com/containers/podman/blob/main/troubleshooting.md)

Yes/No

Additional environment details (AWS, VirtualBox, physical, etc.):

Physical, RHEL 8.5, RHEL 8.6 Beta.

[mheon]

Reproduces locally on main, this seems pretty significant. @cdoern @Luap99 PTAL

[Luap99]

The infra container looks fine but the shared namespaces are not, I only see that uts and ipc are shared.

[Luap99]

Problems seems to be here: https://github.com/containers/podman/blame/main/pkg/specgen/generate/namespaces.go#L486-L490
git blame says 221b1ad

I don't understand why this was added but it is definitely broken in v3.4 as well.

[Luap99]

The problem is that we cannot join the infra namespaces as rootless when the infra already runs in the host namesapce. The oci runtime will fail with eperm on setns. I think we should catch this in podman and set the container to the host ns when the infra already uses the host ns.

I would think the other namespace options have the same problem.

[github-actions]

A friendly reminder that this issue had no activity for 30 days.

[cdoern]

I will tackle this one

[cdoern]

@Luap99 are you working on this? seeing a bunch of commits

[Luap99]

No see the commit description, this is just related to the other issue.