The `$EXISTING_CLUSTER_NODE_HOST_NAME` (examples: `nevaroo`, `jakku` not the FQDN) represent an existing cluster node, via which the new node will join to the cluster.
This node's ssh key (`cat ~/.ssh/id_rsa.pub`) must be added to the `$EXISTING_CLUSTER_NODE_HOST_NAME` under `~/.ssh/authorized_keys`.
Then the node can join the cluster using:
```
pvecm add $EXISTING_CLUSTER_NODE_HOST_NAME --link0 $(tailscale ip -4) --link1 $(tailscale ip -6)
```
### 4. Configure Firewall.
```
# Disable Web Portal on public IP
iptables -A INPUT -p tcp -i vmbr0 --dport 8006 -j DROP
```
### 5. Disable RPC Bind
```
systemctl disable --now rpcbind.target
systemctl disable --now rpcbind.socket
systemctl disable --now rpcbind.service
```
### 5. Disable SSH Access from public internet and enable public key auth.
Make sure to copy your public key using `ssh-copy-id root@proxmox.ip.address`.