add missing IP_PUBLIC variable

opensearch-1.x-node-installer.sh

@@ -21,9 +21,11 @@ MEM_AVAILABLE="$(grep MemTotal /proc/meminfo| grep -o '[0-9]\+')"
 OPNSDIR="/opt/opensearch"
 INDEX_USER="$(tr -dc '[:lower:]' < /dev/urandom | fold -w 24 | head -n1)"
 OPNSREST="$(tr -dc "a-zA-Z0-9" < /dev/urandom | fold -w 32 | head -n1)"
+PUBLIC_IP="$(dig -4 +short myip.opendns.com @resolver1.opendns.com)"
 opens_fts="opensearchproject/opensearch"
 fts_node="fts_os-node"
 max_map_count="512000"
+NL="$(printf '\n  ')"
 
 printwc() {
     printf "%b$2%b" "$1" "${Color_Off}"