Container with podman network not receiving UDP traffic #1045
Description
Issue Description
Upon running a simple python server container listening on a UDP socket with an attached podman network, UDP traffic that is being sent to the port does not arrive.
Versions 5.2.0-dev-5d10f77da and 4.9.4-rhel both were tried with the same results.
This is a MRE of the issue we are having in production. Docker is fine, podman+cni is fine, podman+netavark exhibits this issue. Note restarting our UDP devices or changing the source port is very cumbersome and we wish to avoid this.
Steps to reproduce the issue
Steps to reproduce the issue
- Create Dockerfile
FROM python:latest
WORKDIR /usr/local/bin
COPY server.py .
CMD ["chmod", "+x", "server.py"]
CMD ["server.py"]
- The corresponding server script
#!/bin/python3
import socket
server_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
server_socket.bind(('', 17000))
while True:
message, address = server_socket.recvfrom(1024)
print(f"resceived from: {address}: {message}", flush = True)
podman build . -t podman_udp_testpodman network create podman_udp- Start sending UDP traffic to port 17000 etc with nping:
nping -g 17580 -p 17000 -c 1000000 --udp 127.0.0.1 podman run -p 17000:17000/udp --net podman_udp_network podman_udp_testing
Describe the results you received
No output
Describe the results you expected
Output from the server after receiving packets
podman info output
host:
arch: amd64
buildahVersion: 1.33.8
cgroupControllers:
- cpuset
- cpu
- io
- memory
- hugetlb
- pids
- rdma
- misc
cgroupManager: systemd
cgroupVersion: v2
conmon:
package: conmon-2.1.10-1.el9.x86_64
path: /usr/bin/conmon
version: 'conmon version 2.1.10, commit: fb8c4bf50dbc044a338137871b096eea8041a1fa'
cpuUtilization:
idlePercent: 99.38
systemPercent: 0.28
userPercent: 0.35
cpus: 4
databaseBackend: sqlite
distribution:
distribution: rhel
version: "9.4"
eventLogger: journald
freeLocks: 2032
hostname: ccms-pod
idMappings:
gidmap: null
uidmap: null
kernel: 5.14.0-427.18.1.el9_4.x86_64
linkmode: dynamic
logDriver: journald
memFree: 640634880
memTotal: 8058433536
networkBackend: netavark
networkBackendInfo:
backend: netavark
dns:
package: aardvark-dns-1.10.0-3.el9_4.x86_64
path: /usr/libexec/podman/aardvark-dns
version: aardvark-dns 1.10.0
package: netavark-1.10.3-1.el9.x86_64
path: /usr/libexec/podman/netavark
version: netavark 1.10.3
ociRuntime:
name: crun
package: crun-1.14.3-1.el9.x86_64
path: /usr/bin/crun
version: |-
crun version 1.14.3
commit: 1961d211ba98f532ea52d2e80f4c20359f241a98
rundir: /run/user/0/crun
spec: 1.0.0
+SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +CRIU +YAJL
os: linux
pasta:
executable: ""
package: ""
version: ""
remoteSocket:
exists: false
path: /run/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: false
seccompEnabled: true
seccompProfilePath: /usr/share/containers/seccomp.json
selinuxEnabled: true
serviceIsRemote: false
slirp4netns:
executable: /usr/bin/slirp4netns
package: slirp4netns-1.2.3-1.el9.x86_64
version: |-
slirp4netns version 1.2.3
commit: c22fde291bb35b354e6ca44d13be181c76a0a432
libslirp: 4.4.0
SLIRP_CONFIG_VERSION_MAX: 3
libseccomp: 2.5.2
swapFree: 5367644160
swapTotal: 5368705024
uptime: 583h 32m 27.00s (Approximately 24.29 days)
variant: ""
plugins:
authorization: null
log:
- k8s-file
- none
- passthrough
- journald
network:
- bridge
- macvlan
- ipvlan
volume:
- local
registries:
search:
- registry.access.redhat.com
- registry.redhat.io
- docker.io
store:
configFile: /etc/containers/storage.conf
containerStore:
number: 5
paused: 0
running: 5
stopped: 0
graphDriverName: overlay
graphOptions:
overlay.mountopt: nodev,metacopy=on
graphRoot: /var/lib/containers/storage
graphRootAllocated: 47173337088
graphRootUsed: 20552769536
graphStatus:
Backing Filesystem: xfs
Native Overlay Diff: "false"
Supports d_type: "true"
Supports shifting: "false"
Supports volatile: "true"
Using metacopy: "true"
imageCopyTmpDir: /var/tmp
imageStore:
number: 34
runRoot: /run/containers/storage
transientStore: false
volumePath: /var/lib/containers/storage/volumes
version:
APIVersion: 4.9.4-rhel
Built: 1719829634
BuiltTime: Mon Jul 1 18:27:14 2024
GitCommit: ""
GoVersion: go1.21.11 (Red Hat 1.21.11-1.el9_4)
Os: linux
OsArch: linux/amd64
Version: 4.9.4-rhelPodman in a container
No
Privileged Or Rootless
Privileged
Upstream Latest Release
Yes
Additional environment details
There was no difference from running nping on localhost versus running it on a different machine that can access the podman container
Additional information
Starting the python server first and then starting the UDP sender works as expected but this doesn't help our use case.
Stopping and restarting the UDP sender program while the container is running doesn't help. Only by changing the source port of the UDP sender program does traffic start being received, but we cannot easily change the source port of the UDP traffic.