Run container in created pod with --share net (default) let application crashs for unknown local hostname

I am using podman-compose and ran into a behaviour, I don't understand yet. Respectively I know how to solve the problem, but I don't get it..I have a compose file, which starts Apache NiFi and some other services like nginx, zookeeper etc. It does not matter if I start all services or only NiFi with podman-compose, all the time I get the same error. And the setting of podman-compose is by default to run all containers in one single pod.

After 10 seconds podman logs this: Received trapped signal, beginning shutdown... for NiFi container. The bootstrap logging of NiFi logs a bit more like this, but enough to understand I think: ERROR [NiFi logging handler] org.apache.nifi.StdErr Error: Exception thrown by the agent : java.net.MalformedURLException: Local host name unknown: java.net.UnknownHostException: 4986270786f1: 4986270786f1: Name or service not known podman-compose creates the pod like this: podman pod create --name=<project-name> --share net -p <some-ports> It uses --share net to only share this specific kernel namespace. It can be found at this line. If I create a pod without --share net , podman shares all kernel namespaces (including net) and the problem is solved. It is also solved, if I run --share ipc,pid,uts (cgroups is automatically shared without specifying, I figured out), so without net.

My first question is, why podman-compose has hard coded this parameter?

And my second question is, why a network error is raised if the pod shares only network namespace and does not raise it, when every namespace is shared, as well as every namespace except net is shared? I would expect that it does not raise an error, if only net namespace is shared and raises one if it does not shared..I hope you get it :-)

btw: it runs with docker-compose without any problem..

$ podman version
Version:            1.9.1
RemoteAPI Version:  1
Go Version:         go1.11.6
OS/Arch:            linux/amd64

$ podman info
host:
  arch: amd64
  buildahVersion: 1.14.8
  cgroupVersion: v1
  conmon:
    package: 'conmon: /usr/libexec/podman/conmon'
    path: /usr/libexec/podman/conmon
    version: 'conmon version 2.0.15, commit: '
  cpus: 12
  distribution:
    distribution: debian
    version: "10"
  eventLogger: file
  hostname: <any-hostname>
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 2662
      size: 1
    - container_id: 1
      host_id: 951968
      size: 65536
    uidmap:
    - container_id: 0
      host_id: 2662
      size: 1
    - container_id: 1
      host_id: 951968
      size: 65536
  kernel: 4.19.0-8-amd64
  memFree: 16260124672
  memTotal: 33731375104
  ociRuntime:
    name: runc
    package: 'runc: /usr/sbin/runc'
    path: /usr/sbin/runc
    version: |-
      runc version 1.0.0~rc6+dfsg1
      commit: 1.0.0~rc6+dfsg1-3
      spec: 1.0.1
  os: linux
  rootless: true
  slirp4netns:
    executable: /usr/bin/slirp4netns
    package: 'slirp4netns: /usr/bin/slirp4netns'
    version: |-
      slirp4netns version 1.0.0
      commit: unknown
      libslirp: 4.2.0
  swapFree: 3938185216
  swapTotal: 4000313344
  uptime: 1106h 57m 27.49s (Approximately 46.08 days)
registries:
  search:
  - docker.io
  - quay.io
store:
  configFile: /home/<rootless-user>/.config/containers/storage.conf
  containerStore:
    number: 7
    paused: 0
    running: 6
    stopped: 1
  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 0.7.6
        FUSE library version 3.4.1
        using FUSE kernel interface version 7.27
  graphRoot: /home/<rootless-user>/.local/share/containers/storage
  graphStatus:
    Backing Filesystem: extfs
    Native Overlay Diff: "false"
    Supports d_type: "true"
    Using metacopy: "false"
  imageStore:
    number: 6
  runRoot: /tmp/run-2662/containers
  volumePath: /home/<rootless-user>/.local/share/containers/storage/volumes

I installed podman-compose via downloading master-branch and install it with pip3 install podman-compose-master.zip because of this issue https://github.com/containers/podman-compose/issues/54

If you need more information, let me know :-)

containers / podman-compose

Run container in created pod with --share net (default) let application crashs for unknown local hostname #173