Network interface down with newly installed LXC Container

[wtfka]

Hello,

I have the problem that the network interface does not start with newly installed LXC containers:

root@k8s-server:~# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host noprefixroute
       valid_lft forever preferred_lft forever
2: eth0@if40: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether bc:24:11:20:f3:d9 brd ff:ff:ff:ff:ff:ff link-netnsid 0
root@k8s-server:~# ifup eth0
Could not find command-not-found database. Run 'sudo apt update' to populate it.
ifup: command not found
root@k8s-server:~#

root@proxmox:~# pct config 301
arch: amd64
cores: 1
hostname: k8s-server
memory: 512
net0: name=eth0,bridge=vmbr0,hwaddr=BC:24:11:20:F3:D9,ip=dhcp,type=veth
ostype: ubuntu
rootfs: local-lvm:vm-301-disk-0,size=8G
swap: 512

IPv4 is set to DHCP and IPv6 is disabled. How can I solve this problem?

Thank you very much!

 

[wtfka]

Update:

dhclient -r
dhclient

With these commands it receives an IP address. Unfortunately, this is gone again after a restart.