keyskeysand more keys there are three completely different types of keys that are important when dealing with awsa standard username/password combinationwhich you use to log in to the website the ssh key systemwhich is public/private key system implemented with fileswith your public key fileyou can log in to remote machines the aws access key/secret key systemwhich is just form of username/passwordwhich allows you to have multiple users on the same account (including adding different permissions to each onebut we will not cover those advanced features in this bookto look up our access/secret keyswe go back to the aws console and click on our name in the top-right cornerthen select security credentials now at the bottom of the screenthere should be our access key that may look something like aakiit hhf iusn ocaawhich we will use as an example in this now edit the configuration file this is standard ini filea text file where sections start by having their names in brackets and options are specified in the name=value format the first section is the aws info section and you should copy and paste your keys there[aws infoaws_access_key_id aakiit hhf iusn ocaa aws_secret_access_key nowwe come to the fun part that is defining cluster starcluster allows you to define as many different clusters as you wish the starting file has one called smallcluster it is defined in the cluster smallcluster section we will edit it to read as follows[cluster myclusterkeyname mykey cluster_size this changes the number of nodes to instead of the default of two we can additionally specify which type of instance each node will be and what the initial image is (rememberan image is the initial diskwhich defines what operating system you will be running and what software is installedstarcluster has few predefined imagesbut you can also build your own