Here are the notes regarding the setup (migration to): Hetner cloud KVM VPS 4GB RAM + CentOS 6 + OpenVZ 6 + HyperVM beta.
Information is likely relevant only to someone who is setting up new OpenVZ server and already using one.

Install openvz node + hypervm?: https://internetlifeforum.com/virtualisation/2607-script-install-openvz-hypervm-epel-vzdump-centos/
worked! if failed, then:
installed fail2ban
Hetzner floating IP worked immediately on ovz virtual server i created on that cloud VPS, no needed ANY config., HyperVM assigned it when i manually in hyperVM added the IP to a VPS (not by adding hypervm ip pool - as its single ip and i do not know how subnet should look like in this case)
check /etc/vz/vz.conf, add some IPTABLES_MODULES? i had these additional: iptable_nat ip_nat_ftp xt_connlimit
then run: modprobe iptable_nat;modprobe ip_nat_ftp;modprobe xt_connlimit
then on source OVZ node (from which i am migrating virtual servers) i ran vzdump_all_vps2_fix script. It will:
- create dumps (keep vps running)
- copy it to new server and initiate restoring
- run vps and run command that will replace old ip by new one in vps files
Fixes for the script: modify route on the source server to redirect VPS traffic to new server
- Import raw VPS in hyperVM, send an e-mail to VPS owner with new IP (things to note: controlling their nameservers? cloudflare change?), check that services on VPSs running
- copy over /root scripts, .bashrc aliases, cron.d/myjobs ?
- Check vz.conf: https://internetlifeforum.com/virtualisation/4659-how-change-way-hypervm-create-new-openvz-vps/
- Check if any existing VPSs has additional IPs assigned to them to reproduce it on new server
- If using WHMCS billing system, fix WHMCS to HyperVM api: https://internetlifeforum.com/virtualisation/7616-hypervm-2-1-0-dev-beta-how-i-made-use-vswap-fqdn-hostnames-whmcs-fix/

- restore custom /usr/local/lxlabs/hypervm/httpdocs/lib/vps/driver/vps__openvzlib.phps if i customized it
- backup important files, migration scripts on the old server (in new node root)

- Need more dsk space on the host node, check Hetzner console options or setup NFS / SSHFS network filesystem?
- Enable ipset blocking of Firehol Leve1 list.

Some suggested parameters for the /etc/sysctl.conf
net.ipv4.ip_forward = 1
net.ipv6.conf.default.forwarding = 1
net.ipv6.conf.all.forwarding = 1
net.ipv4.conf.default.proxy_arp = 0

# Enables source route verification
net.ipv4.conf.all.rp_filter = 1

# Enables the magic-sysrq key
kernel.sysrq = 1

# We do not want all our interfaces to send redirects
net.ipv4.conf.default.send_redirects = 1
net.ipv4.conf.all.send_redirects = 0