proxmox issue

Follow this base proxmox install
https://pve.proxmox.com/wiki/Install_Proxmox_VE_on_Debian_Jessie

Follow https://wiki.hetzner.de/index.php/Proxmox_VE/en to setup (do exactly what the tutorial want, including ipv6 subnet)
- sysctl
- Network configuration host system KVM/Routed
- Network configuration guest system KVM/Routed

Follow https://www.kiloroot.com/proxmox-kimsufi-ovh-soyoustart-ipv6-host-multiple-containers-and-virtual-machines-on-a-single-kimsufi-server-using-ipv6-and-proxmox/ to make internal networking (bonus session)

Current issue:
- LXC
    - Ubuntu 16.04: ipv4 public and local works, ipv6 work, container with private ip only cannot connect internet
    - centos 7: cannot add 2 interface, eth0 and eth1. ipv4 public works, if I add private IP, it was not work, even there is route config
- KVM
    - centos 7: public ipv4 work, local doesnt