fix: preseed known_hosts for kubeadm SSH operations

nixos/kubeadm/scripts/reset-cluster-nodes.sh

@@ -14,7 +14,7 @@ fi
 source "$INVENTORY_FILE"
 
 SSH_USER="${SSH_USER:-micqdf}"
-SSH_OPTS="${SSH_OPTS:- -o BatchMode=yes -o StrictHostKeyChecking=accept-new }"
+SSH_OPTS="${SSH_OPTS:--o BatchMode=yes -o StrictHostKeyChecking=accept-new}"
 
 declare -A NODE_IPS=()
 
@@ -58,6 +58,15 @@ if [ "${#NODE_IPS[@]}" -eq 0 ]; then
   exit 1
 fi
 
+mkdir -p "$HOME/.ssh"
+chmod 700 "$HOME/.ssh"
+touch "$HOME/.ssh/known_hosts"
+chmod 600 "$HOME/.ssh/known_hosts"
+for node_name in "${!NODE_IPS[@]}"; do
+  ssh-keygen -R "${NODE_IPS[$node_name]}" >/dev/null 2>&1 || true
+  ssh-keyscan -H "${NODE_IPS[$node_name]}" >> "$HOME/.ssh/known_hosts" 2>/dev/null || true
+done
+
 reset_node() {
   local node_name="$1"
   local node_ip="$2"