Hello.

I have tried Podman in Fedora 31. Not a rootless setup.

Software versions:

podman-1.6.2-2.fc31.x86_64
containernetworking-plugins-0.8.2-2.1.dev.git485be65.fc31.x86_64

I have created two containers:

# podman container run -d --name nginx_1 -p 80:80 nginx
# podman container run -d --name nginx_2 -p 81:80 nginx

Then I wanted to make sure that they start on boot.

According to RHEL 7 documentation,
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux_atomic_host/7/html/managing_containers/running_containers_as_systemd_services_with_podman
, I am supposed to create systemd units. OK, let's take the documented
form of the unit and turn it into a template:

[Unit]
Description=Container %i

[Service]
ExecStart=/usr/bin/podman start -a %i
ExecStop=/usr/bin/podman stop -t 2 %i

[Install]
WantedBy=multi-user.target

This doesn't work if there is more than one container. The error
is:

Nov 04 21:35:57 podman[2268]: time="2019-11-04T21:35:57+05:00"
level=error msg="Error adding network: failed to allocate for range 0:
10.88.0.19 has been allocated to
ace2de4405205a9a7674a2524cd67c1f0e395a9234b0456c55881a1a4add6019,
duplicate allocation is not allowed"
Nov 04 21:35:57 podman[2268]: time="2019-11-04T21:35:57+05:00"
level=error msg="Error while adding pod to CNI network \"podman\":
failed to allocate for range 0: 10.88.0.19 has been allocated to
ace2de4405205a9a7674a2524cd67c1f0e395a9234b0456c55881a1a4add6019,
duplicate allocation is not allowed"
Nov 04 21:35:57 podman[2268]: Error: unable to start container
ace2de4405205a9a7674a2524cd67c1f0e395a9234b0456c55881a1a4add6019:
error configuring network namespace for container
ace2de4405205a9a7674a2524cd67c1f0e395a9234b0456c55881a1a4add6019:
failed to allocate for range 0: 10.88.0.19 has been allocated to
ace2de4405205a9a7674a2524cd67c1f0e395a9234b0456c55881a1a4add6019,
duplicate allocation is not allowed

(as you can see, the conflict is against the container itself)

Apparently different runs of podman need to be serialized against each
other. This works:

[Unit]
Description=Container %i
Wants=network-online.target
After=network-online.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=flock /run/lock/subsys/container.lck /usr/bin/podman start %i
ExecStop=/usr/bin/podman stop -t 2 %i

[Install]
WantedBy=multi-user.target

Questions:

a) Why isn't some equivalent of this unit shipped with podman? Or, am
I missing some package that ships it?
b) Why isn't the necessary locking built into podman itself? Or, is it
a bug in containernetworking-plugins?

--
Alexander E. Patrakov
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