dhcpcd creates and deletes veth* interfaces in thousands

Question

I run a RPi4 (4GB) with Raspbian 10 (buster) from a SSD. It's running docker containters with nginx, nextcloud, pihole and some others.

The RPi crashes from time to time. I found out it runs out of inodes on /run. In /run/dhcpcd it creates tenthousands of files named ntp.conf.veth*.

/etc/syslog shows

Jun 24 09:56:20 tsht2 systemd[15436]: run-docker-runtime\x2drunc-moby-b10ec62cf0cda36d219d61dc0dfd363fbef69eb7a9570669abc5a1ac01a6b29b-runc.qcYBjl.mount: Succeeded.
Jun 24 09:56:20 tsht2 systemd[1]: run-docker-runtime\x2drunc-moby-b10ec62cf0cda36d219d61dc0dfd363fbef69eb7a9570669abc5a1ac01a6b29b-runc.qcYBjl.mount: Succeeded.
Jun 24 09:56:26 tsht2 kernel: [2548602.562955] br-a728ad951bf0: port 1(vethde83d77) entered blocking state
Jun 24 09:56:26 tsht2 kernel: [2548602.562976] br-a728ad951bf0: port 1(vethde83d77) entered disabled state
Jun 24 09:56:26 tsht2 kernel: [2548602.564254] device vethde83d77 entered promiscuous mode
Jun 24 09:56:26 tsht2 dhcpcd[569]: veth1346966: waiting for carrier
Jun 24 09:56:26 tsht2 kernel: [2548602.644517] IPv6: ADDRCONF(NETDEV_CHANGE): veth1346966: link becomes ready
Jun 24 09:56:26 tsht2 kernel: [2548602.644648] IPv6: ADDRCONF(NETDEV_CHANGE): vethde83d77: link becomes ready
Jun 24 09:56:26 tsht2 kernel: [2548602.644739] br-a728ad951bf0: port 1(vethde83d77) entered blocking state
Jun 24 09:56:26 tsht2 kernel: [2548602.644747] br-a728ad951bf0: port 1(vethde83d77) entered forwarding state
Jun 24 09:56:26 tsht2 dhcpcd[569]: vethde83d77: IAID b7:de:df:86
Jun 24 09:56:26 tsht2 dhcpcd[569]: vethde83d77: adding address fe80::2e78:c676:b588:f7f3
Jun 24 09:56:26 tsht2 dhcpcd[569]: veth1346966: carrier acquired
Jun 24 09:56:26 tsht2 avahi-daemon[354]: Joining mDNS multicast group on interface vethde83d77.IPv6 with address fe80::2e78:c676:b588:f7f3.
Jun 24 09:56:26 tsht2 avahi-daemon[354]: New relevant interface vethde83d77.IPv6 for mDNS.
Jun 24 09:56:26 tsht2 avahi-daemon[354]: Registering new address record for fe80::2e78:c676:b588:f7f3 on vethde83d77.*.
Jun 24 09:56:26 tsht2 dhcpcd[569]: veth1346966: IAID bd:e1:94:fa
Jun 24 09:56:26 tsht2 dhcpcd[569]: veth1346966: adding address fe80::f815:8b2d:3cb9:304e
Jun 24 09:56:26 tsht2 avahi-daemon[354]: Joining mDNS multicast group on interface veth1346966.IPv6 with address fe80::f815:8b2d:3cb9:304e.
Jun 24 09:56:26 tsht2 avahi-daemon[354]: New relevant interface veth1346966.IPv6 for mDNS.
Jun 24 09:56:26 tsht2 avahi-daemon[354]: Registering new address record for fe80::f815:8b2d:3cb9:304e on veth1346966.*.
Jun 24 09:56:26 tsht2 dockerd[604]: time="2022-06-24T09:56:26.195173647+02:00" level=warning msg="path in container /dev/ttyACM0 already exists in privileged mode" container=7a181a217e7877be9e952f693218dbecb8db8593896895b309610431e5c77ba6
Jun 24 09:56:26 tsht2 dockerd[604]: time="2022-06-24T09:56:26.195252202+02:00" level=warning msg="path in container /dev/ttyACM1 already exists in privileged mode" container=7a181a217e7877be9e952f693218dbecb8db8593896895b309610431e5c77ba6
Jun 24 09:56:26 tsht2 containerd[586]: time="2022-06-24T09:56:26.245789719+02:00" level=info msg="loading plugin \"io.containerd.event.v1.publisher\"..." runtime=io.containerd.runc.v2 type=io.containerd.event.v1
Jun 24 09:56:26 tsht2 containerd[586]: time="2022-06-24T09:56:26.246220528+02:00" level=info msg="loading plugin \"io.containerd.internal.v1.shutdown\"..." runtime=io.containerd.runc.v2 type=io.containerd.internal.v1
Jun 24 09:56:26 tsht2 containerd[586]: time="2022-06-24T09:56:26.246278935+02:00" level=info msg="loading plugin \"io.containerd.ttrpc.v1.task\"..." runtime=io.containerd.runc.v2 type=io.containerd.ttrpc.v1
Jun 24 09:56:26 tsht2 containerd[586]: time="2022-06-24T09:56:26.246754078+02:00" level=info msg="starting signal loop" namespace=moby path=/run/containerd/io.containerd.runtime.v2.task/moby/7a181a217e7877be9e952f693218dbecb8db8593896895b309610431e5c77ba6 pid=23770 runtime=io.containerd.runc.v2
Jun 24 09:56:26 tsht2 dhcpcd[569]: veth1346966: soliciting a DHCP lease
Jun 24 09:56:26 tsht2 avahi-daemon[354]: Interface veth1346966.IPv6 no longer relevant for mDNS.
Jun 24 09:56:26 tsht2 avahi-daemon[354]: Leaving mDNS multicast group on interface veth1346966.IPv6 with address fe80::f815:8b2d:3cb9:304e.
Jun 24 09:56:26 tsht2 dhcpcd[569]: veth1346966: carrier lost
Jun 24 09:56:26 tsht2 avahi-daemon[354]: Withdrawing address record for fe80::f815:8b2d:3cb9:304e on veth1346966.
Jun 24 09:56:26 tsht2 dhcpcd[569]: veth1346966: deleting address fe80::f815:8b2d:3cb9:304e
Jun 24 09:56:26 tsht2 kernel: [2548603.429722] br-a728ad951bf0: port 1(vethde83d77) entered disabled state
Jun 24 09:56:26 tsht2 kernel: [2548603.431409] eth0: renamed from veth1346966
Jun 24 09:56:26 tsht2 kernel: [2548603.480479] br-a728ad951bf0: port 1(vethde83d77) entered blocking state
Jun 24 09:56:26 tsht2 kernel: [2548603.480489] br-a728ad951bf0: port 1(vethde83d77) entered forwarding state
Jun 24 09:56:27 tsht2 dhcpcd[569]: vethde83d77: soliciting a DHCP lease
Jun 24 09:56:27 tsht2 containerd[586]: time="2022-06-24T09:56:27.039926533+02:00" level=error msg="add cg to OOM monitor" error="cgroups: memory cgroup not supported on this system"
Jun 24 09:56:27 tsht2 dhcpcd[569]: vethde83d77: soliciting an IPv6 router
Jun 24 09:56:27 tsht2 dhcpcd[569]: veth1346966: removing interface
Jun 24 09:56:27 tsht2 dhcpcd[569]: vethde83d77: carrier lost
Jun 24 09:56:27 tsht2 dhcpcd[569]: vethde83d77: deleting address fe80::2e78:c676:b588:f7f3
Jun 24 09:56:27 tsht2 avahi-daemon[354]: Withdrawing address record for fe80::2e78:c676:b588:f7f3 on vethde83d77.
Jun 24 09:56:27 tsht2 avahi-daemon[354]: Leaving mDNS multicast group on interface vethde83d77.IPv6 with address fe80::2e78:c676:b588:f7f3.
Jun 24 09:56:27 tsht2 avahi-daemon[354]: Interface vethde83d77.IPv6 no longer relevant for mDNS.
Jun 24 09:56:27 tsht2 dhcpcd[569]: vethde83d77: carrier acquired
Jun 24 09:56:27 tsht2 dhcpcd[569]: vethde83d77: IAID b7:de:df:86
Jun 24 09:56:27 tsht2 dhcpcd[569]: vethde83d77: adding address fe80::2e78:c676:b588:f7f3
Jun 24 09:56:27 tsht2 avahi-daemon[354]: Joining mDNS multicast group on interface vethde83d77.IPv6 with address fe80::2e78:c676:b588:f7f3.
Jun 24 09:56:27 tsht2 avahi-daemon[354]: New relevant interface vethde83d77.IPv6 for mDNS.
Jun 24 09:56:27 tsht2 avahi-daemon[354]: Registering new address record for fe80::2e78:c676:b588:f7f3 on vethde83d77.*.
Jun 24 09:56:27 tsht2 avahi-daemon[354]: Registering new address record for fe80::403f:b7ff:fede:df86 on vethde83d77.*.
Jun 24 09:56:27 tsht2 dhcpcd[569]: vethde83d77: soliciting a DHCP lease
Jun 24 09:56:27 tsht2 dhcpcd[569]: vethde83d77: soliciting an IPv6 router
Jun 24 09:56:29 tsht2 ntpd[587]: Listen normally on 76549 vethde83d77 [fe80::2e78:c676:b588:f7f3%77716]:123
Jun 24 09:56:29 tsht2 ntpd[587]: Listen normally on 76550 vethde83d77 [fe80::403f:b7ff:fede:df86%77716]:123
Jun 24 09:56:29 tsht2 ntpd[587]: new interface(s) found: waking up resolver

Is this a docker problem? Is it a dhcpcd problem? Where can I start to investigate further?

I haven't changed the default config of dhcpcd. If it's needed, I can post it here. I pinned the IP in my Fritz!Box, so I don't have to set a static IP. I saw this, but that doesn't seem to be related, since I assume I have a newer version of the dhcpcd (8.1.2-1) and my problem isn't the log-spam, but the file-spam.