Explicitly specifying platform slows down container start

[rgov]

Issue Description

Starting a container with the --platform option explicitly provided rather than inferred from the container image seems to add a delay to starting the container.

I suspect this is due to unnecessary network requests. When I disconnect my Wi-Fi, the container start time decreases, probably because it skips whatever network request(s) is causing the delay.

Steps to reproduce the issue

$ time podman run --rm -it alpine:3 arch
aarch64
...  0.03s user 0.02s system 11% cpu 0.433 total

$ time podman run --rm -it --platform=linux/arm64 alpine:3 arch
aarch64
...  0.04s user 0.02s system 3% cpu 1.858 total

Describe the results you received

With the --platform flag the time is 4.5x as long in the above example.

Describe the results you expected

There should be no difference in container start time when explicitly specifying the platform.

podman info output

host:
  arch: arm64
  buildahVersion: 1.32.0
  cgroupControllers:
  - cpu
  - io
  - memory
  - pids
  cgroupManager: systemd
  cgroupVersion: v2
  conmon:
    package: conmon-2.1.7-2.fc38.aarch64
    path: /usr/bin/conmon
    version: 'conmon version 2.1.7, commit: '
  cpuUtilization:
    idlePercent: 95.18
    systemPercent: 1.72
    userPercent: 3.1
  cpus: 1
  databaseBackend: boltdb
  distribution:
    distribution: fedora
    variant: coreos
    version: "38"
  eventLogger: journald
  freeLocks: 2038
  hostname: localhost.localdomain
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 100000
      size: 1000000
    uidmap:
    - container_id: 0
      host_id: 501
      size: 1
    - container_id: 1
      host_id: 100000
      size: 1000000
  kernel: 6.5.5-200.fc38.aarch64
  linkmode: dynamic
  logDriver: journald
  memFree: 1407299584
  memTotal: 1980387328
  networkBackend: netavark
  networkBackendInfo:
    backend: netavark
    dns:
      package: aardvark-dns-1.7.0-1.fc38.aarch64
      path: /usr/libexec/podman/aardvark-dns
      version: aardvark-dns 1.7.0
    package: netavark-1.7.0-1.fc38.aarch64
    path: /usr/libexec/podman/netavark
    version: netavark 1.7.0
  ociRuntime:
    name: crun
    package: crun-1.9.2-1.fc38.aarch64
    path: /usr/bin/crun
    version: |-
      crun version 1.9.2
      commit: 35274d346d2e9ffeacb22cc11590b0266a23d634
      rundir: /run/user/501/crun
      spec: 1.0.0
      +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +CRIU +LIBKRUN +WASM:wasmedge +YAJL
  os: linux
  pasta:
    executable: /usr/bin/pasta
    package: passt-0^20230908.g05627dc-1.fc38.aarch64
    version: |
      pasta 0^20230908.g05627dc-1.fc38.aarch64-pasta
      Copyright Red Hat
      GNU General Public License, version 2 or later
        <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
      This is free software: you are free to change and redistribute it.
      There is NO WARRANTY, to the extent permitted by law.
  remoteSocket:
    exists: true
    path: /run/user/501/podman/podman.sock
  security:
    apparmorEnabled: false
    capabilities: 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: true
    seccompEnabled: true
    seccompProfilePath: /usr/share/containers/seccomp.json
    selinuxEnabled: true
  serviceIsRemote: true
  slirp4netns:
    executable: /usr/bin/slirp4netns
    package: slirp4netns-1.2.1-1.fc38.aarch64
    version: |-
      slirp4netns version 1.2.1
      commit: 09e31e92fa3d2a1d3ca261adaeb012c8d75a8194
      libslirp: 4.7.0
      SLIRP_CONFIG_VERSION_MAX: 4
      libseccomp: 2.5.3
  swapFree: 0
  swapTotal: 0
  uptime: 0h 9m 36.00s
plugins:
  authorization: null
  log:
  - k8s-file
  - none
  - passthrough
  - journald
  network:
  - bridge
  - macvlan
  - ipvlan
  volume:
  - local
registries:
  search:
  - docker.io
store:
  configFile: /var/home/core/.config/containers/storage.conf
  containerStore:
    number: 8
    paused: 0
    running: 0
    stopped: 8
  graphDriverName: overlay
  graphOptions: {}
  graphRoot: /var/home/core/.local/share/containers/storage
  graphRootAllocated: 106769133568
  graphRootUsed: 13204803584
  graphStatus:
    Backing Filesystem: xfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Supports shifting: "false"
    Supports volatile: "true"
    Using metacopy: "false"
  imageCopyTmpDir: /var/tmp
  imageStore:
    number: 61
  runRoot: /run/user/501/containers
  transientStore: false
  volumePath: /var/home/core/.local/share/containers/storage/volumes
version:
  APIVersion: 4.7.0
  Built: 1695839065
  BuiltTime: Wed Sep 27 11:24:25 2023
  GitCommit: ""
  GoVersion: go1.20.8
  Os: linux
  OsArch: linux/arm64
  Version: 4.7.0

Podman in a container

No

Privileged Or Rootless

Rootless

Upstream Latest Release

Yes

Additional environment details

No response

Additional information

No response

[vrothberg]

Thanks for reaching out, @rgov.

Please see #17063 for the details on the issue.