added ping to the entrypoint too

entrypoint.sh

@@ -1,8 +1,11 @@
 set -e
-isConnected="/opt/mssql-tools/bin/sqlcmd -S $1 -U $2 -P $3"
+
+while ! ping -c3 $1 &>/dev/null; do echo "Ping Fail - `date`"; done ; echo "Host Found - `date`";
+
+testConnection="/opt/mssql-tools/bin/sqlcmd -S $1 -U $2 -P $3"
 
-until $isConnected; do
->&2 echo "SQL Server is starting up..."
+until $testConnection; do
+>&2 echo "SQL Server is starting up.."
 sleep 1
 done