There is a spelling mistake in your command that is why you are getting the error. You are using hbase-tabel customers123 instead of hbase-table customers123.
Try this
sqoop import --connect jdbc:mysql://mysqldb.edu.cloudlab.com/retail_db --username labuser --password edureka --table customers - -hbase-table customers123 --hbase-row-key customer_id --column-family cf1 --hbase-create-table -m 1