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:
A) try this OVZ install tut. https://www.howtoforge.com/installing-and-using-openvz-on-centos-6.0
B) Virtualizor (only $1 per VPS): https://internetlifeforum.com/virtualisation/8351-virtualizor-kvm-openvz-installation-tutorial-centos-6-9-64bit/
Hypervm alternatives:
A) Vz to LXC in proxmox: https://internetlifeforum.com/virtualisation/8529-migrate-openvz-6-vpss-into-lxc-proxmox-server/
B) hypervm panel alrernative free, easy: https://sourceforge.net/projects/fosvm/
C) WebVz, free panel? http://webvz.sourceforge.net/download.html
D) vmmanager (centos6_64+ovz(6?), 2vps free, then $8/mo.: https://docs.ispsystem.com/vmmanager-ovz/setup-and-configuration/hardware-requirements
E) solusvm free trial can convert OVZ6 to OVZ7! : https://solusvm.com/pricing/
F) aventurine 1VPS only, more toooo expensive .iso: https://www.aventurin.net/index.php?page=get-aventurine
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 ***** (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