trying to get all comom runtime out of master conf

common.sh

@@ -77,4 +77,46 @@ require_var() {
         echo "Error: Required variable $var is not set."
         exit 1
     fi
-}
+}
+
+# Detect local hostname
+LOCAL_HOSTNAME="$(hostname)"
+if [[ "$LOCAL_HOSTNAME" == "$HOST1" ]]; then
+    LOCAL_SERVER_NAME="$HOST1"
+    REMOTE_SERVER_NAME="$HOST2"
+elif [[ "$LOCAL_HOSTNAME" == "$HOST2" ]]; then
+    LOCAL_SERVER_NAME="$HOST2"
+    REMOTE_SERVER_NAME="$HOST1"
+else
+    echo "Error: Local hostname ($LOCAL_HOSTNAME) not recognized."
+    exit 1
+fi
+echo "Local server: $LOCAL_SERVER_NAME"
+echo "Remote server: $REMOTE_SERVER_NAME"
+
+#-----------------------------------------------------------------------------------------------
+#--------------------------- Remote Server Ip Resolution ----------------------------------------
+#-----------------------------------------------------------------------------------------------
+# Resolve Tailscale IP dynamically
+REMOTE_SERVER=$(tailscale ip -4 "$REMOTE_SERVER_NAME" 2>/dev/null)
+if [[ -z "$REMOTE_SERVER" ]]; then
+    echo "Error: Could not resolve Tailscale IP for $REMOTE_SERVER_NAME"
+    exit 1
+fi
+
+#-----------------------------------------------------------------------------------------------
+#----------------------------- SSH Key Mapping --------------------------------------------------
+#-----------------------------------------------------------------------------------------------
+
+declare -A SSH_KEYS
+SSH_KEYS["$HOST1|$HOST2"]="/root/.ssh/Gmer4Lfe-rsync-key"
+SSH_KEYS["$HOST2|$HOST1"]="/root/.ssh/Jayred365-rsync-key"
+
+KEY_ID="$LOCAL_SERVER_NAME|$REMOTE_SERVER_NAME"
+if [[ -n "${SSH_KEYS[$KEY_ID]}" ]]; then
+    SSH_KEY="${SSH_KEYS[$KEY_ID]}"
+else
+    echo "Error: No SSH key defined for $LOCAL_SERVER_NAME → $REMOTE_SERVER_NAME"
+    exit 1
+fi
+echo "Using SSH key: $SSH_KEY"