podman sets (& overrides) the HOSTNAME env variable

[paravoid]

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

/kind bug

Description

I'm trying to run an image that made the (questionable) choice to bind the network server to the environment's HOSTNAME. Therefore, I'd like to pass HOSTNAME=0.0.0.0 in the container's environment.

However, it seems that podman sets the HOSTNAME environment variable unconditionally to the container (or pod's) hostname. What's worse is that it's being set, even if one passes -e HOSTNAME=something-else.

Steps to reproduce the issue:

1. podman run -h foo -e HOSTNAME=bar --rm busybox /bin/sh -c 'echo $HOSTNAME'
2. podman run -e HOSTNAME=bar --rm busybox /bin/sh -c 'echo $HOSTNAME'

Describe the results you received:

1. foo
2. ad76a346f1fa

Describe the results you expected:

1. bar
2. bar

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

Output of podman version:

Version:      2.2.1
API Version:  2.1.0
Go Version:   go1.15.6
Built:        Thu Jan  1 02:00:00 1970
OS/Arch:      linux/amd64

Output of podman info --debug:

host:
  arch: amd64
  buildahVersion: 1.18.0
  cgroupManager: systemd
  cgroupVersion: v2
  conmon:
    package: 'conmon: /usr/libexec/podman/conmon'
    path: /usr/libexec/podman/conmon
    version: 'conmon version 2.0.20, commit: unknown'
  cpus: 4
  distribution:
    distribution: debian
    version: "10"
  eventLogger: journald
  hostname: donald
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 493216
      size: 65536
    uidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 493216
      size: 65536
  kernel: 5.10.0-1-amd64
  linkmode: dynamic
  memFree: 2339422208
  memTotal: 12270800896
  ociRuntime:
    name: crun
    package: 'crun: /usr/bin/crun'
    path: /usr/bin/crun
    version: |-
      crun version 0.15.1
      commit: eb0145e5ad4d8207e84a327248af76663d4e50dd
      spec: 1.0.0
      +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +YAJL
  os: linux
  remoteSocket:
    exists: true
    path: /run/user/1000/podman/podman.sock
  rootless: true
  slirp4netns:
    executable: /usr/bin/slirp4netns
    package: 'slirp4netns: /usr/bin/slirp4netns'
    version: |-
      slirp4netns version 1.0.1
      commit: 6a7b16babc95b6a3056b33fb45b74a6f62262dd4
      libslirp: 4.4.0
  swapFree: 0
  swapTotal: 0
  uptime: 50h 22m 20.11s (Approximately 2.08 days)
registries:
  search:
  - docker.io
store:
  configFile: /home/user/.config/containers/storage.conf
  containerStore:
    number: 5
    paused: 0
    running: 3
    stopped: 2
  graphDriverName: overlay
  graphOptions:
    overlay.mount_program:
      Executable: /usr/bin/fuse-overlayfs
      Package: 'fuse-overlayfs: /usr/bin/fuse-overlayfs'
      Version: |-
        fusermount3 version: 3.4.1
        fuse-overlayfs: version 1.1.0
        FUSE library version 3.4.1
        using FUSE kernel interface version 7.27
  graphRoot: /home/user/.local/share/containers/storage
  graphStatus:
    Backing Filesystem: extfs
    Native Overlay Diff: "false"
    Supports d_type: "true"
    Using metacopy: "false"
  imageStore:
    number: 7
  runRoot: /run/user/1000/containers
  volumePath: /home/user/.local/share/containers/storage/volumes
version:
  APIVersion: 2.1.0
  Built: 0
  BuiltTime: Thu Jan  1 02:00:00 1970
  GitCommit: ""
  GoVersion: go1.15.6
  OsArch: linux/amd64
  Version: 2.2.1

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

$ dpkg-query -W podman
podman	2.2.1+dfsg1-1

Have you tested with the latest version of Podman and have you checked the Podman Troubleshooting Guide?

Yes

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

Physical.

[mheon]

I'll take this

[mheon]

Fix in #8892