REST APIv2 - rootless - hostname not added to /etc/hosts

[psakar]

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

/kind bug

Description

Container created via REST APIv2 is unable to resolve its hostname because the assigned hostname is missing in container /etc/hosts

Steps to reproduce the issue:

# start podman REST API
podman --log-level=debug system service -t 0 tcp:localhost:8880 2>&1>/tmp/podman-rest.log &

curl -X POST -H "Content-Type: application/json" 'http://127.0.0.1:8880/containers/create?name=test' --data '{"name":"test","Image":"localhost/test:latest", "Cmd":["/bin/sh", "-c", "tail -2 /etc/hosts"]}'
curl -X POST -H "Content-Type: application/json" 'http://127.0.0.1:8880/containers/test/start'
curl --output - -H "Content-Type: application/json" "http://127.0.0.1:8880/containers/test/logs?stdout=true&stderr=true"

Describe the results you received:
Last two lines from file /etc/hosts from my laptop

Describe the results you expected:

# used by slirp4netns
10.0.2.100	3ff0b3519d00 test

(Value 3ff0b3519d00 would be different ...)

Additional information you deem important (e.g. issue happens only occasionally):
May be because netmode is not set ? Applying following patch fixes the issue (most probably wrong, just to test)

diff --git a/pkg/api/handlers/compat/containers_create.go b/pkg/api/handlers/compat/containers_create.go
index 0579da8de..6b92935b9 100644
--- a/pkg/api/handlers/compat/containers_create.go
+++ b/pkg/api/handlers/compat/containers_create.go
@@ -144,7 +144,7 @@ func makeCreateConfig(ctx context.Context, containerConfig *config.Config, input
 		IPAddress:    "",
 		LinkLocalIP:  nil, // docker-only
 		MacAddress:   input.MacAddress,
-		// NetMode:      nil,
+		NetMode:      namespaces.NetworkMode("slirp4netns"),
 		Network:      input.HostConfig.NetworkMode.NetworkName(),
 		NetworkAlias: nil, // docker-only now
 		PortBindings: input.HostConfig.PortBindings,

Output of podman version:

Version:      2.1.1
API Version:  2.0.0
Go Version:   go1.13.15
Built:        Wed Sep 30 21:51:15 2020
OS/Arch:      linux/amd64

Output of podman info --debug:

host:
  arch: amd64
  buildahVersion: 1.16.1
  cgroupManager: systemd
  cgroupVersion: v2
  conmon:
    package: conmon-2.0.21-2.fc31.x86_64
    path: /usr/bin/conmon
    version: 'conmon version 2.0.21, commit: d9f047cb413248e30a1ec560547d9b203396c31b'
  cpus: 8
  distribution:
    distribution: fedora
    version: "31"
  eventLogger: journald
  hostname: localhost
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 21528
      size: 1
    - container_id: 1
      host_id: 100000
      size: 65536
    uidmap:
    - container_id: 0
      host_id: 21528
      size: 1
    - container_id: 1
      host_id: 100000
      size: 65536
  kernel: 5.8.11-100.fc31.x86_64
  linkmode: dynamic
  memFree: 1259569152
  memTotal: 16381120512
  ociRuntime:
    name: crun
    package: crun-0.15-5.fc31.x86_64
    path: /usr/bin/crun
    version: |-
      crun version 0.15
      commit: 56ca95e61639510c7dbd39ff512f80f626404969
      spec: 1.0.0
      +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +YAJL
  os: linux
  remoteSocket:
    path: /run/user/21528/podman/podman.sock
  rootless: true
  slirp4netns:
    executable: /bin/slirp4netns
    package: slirp4netns-1.1.4-1.fc31.x86_64
    version: |-
      slirp4netns version 1.1.4
      commit: b66ffa8e262507e37fca689822d23430f3357fe8
      libslirp: 4.1.0
      SLIRP_CONFIG_VERSION_MAX: 1
  swapFree: 8252289024
  swapTotal: 8252289024
  uptime: 7h 55m 36.8s (Approximately 0.29 days)
registries:
  search:
  - registry.fedoraproject.org
  - registry.access.redhat.com
  - registry.centos.org
  - docker.io
store:
  configFile: /home/psakar/.config/containers/storage.conf
  containerStore:
    number: 3
    paused: 0
    running: 0
    stopped: 3
  graphDriverName: vfs
  graphOptions: {}
  graphRoot: /home/psakar/.local/share/containers/storage
  graphStatus: {}
  imageStore:
    number: 67
  runRoot: /run/user/21528/run
  volumePath: /home/psakar/.local/share/containers/storage/volumes
version:
  APIVersion: 2.0.0
  Built: 1601495475
  BuiltTime: Wed Sep 30 21:51:15 2020
  GitCommit: ""
  GoVersion: go1.13.15
  OsArch: linux/amd64
  Version: 2.1.1

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

podman-2.1.1-3.fc31.x86_64

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

Yes (not tested with master)

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

[psakar]

related to testcontainers/testcontainers-java#2088 and #7235

[baude]

@psakar could you confirm if you are running the service as rootfull or rootless?

[baude]

@psakar im asking because i just ran your reproducer with upstream main branch and it ran correctly as rootful.

[psakar]

@baude rootless (as noted in title)

[baude]

@psakar ty! i cannot believe i missed that. The # instead of $ was probably confusing me. I'll take another peek.

[baude]

Ok, I can reproduce this.