Rubber Capistrano Task to create/delete users across your cluster.

cap_rubber_user_manage.rb

# This will create a user with a default password of #{username}123 
# then the first time they connect they are prompted to change their password

# once the user is created in your local ./tmp directory you'll have the 
# private and public keys for the new user

    desc "Create a user on the servers"
    require "cocaine"
    task :create_server_user do
      set(:user_to_add, Capistrano::CLI.ui.ask("USERNAME you'd like to add: ") )
      key_file = File.join(File.dirname(__FILE__), '../../tmp', user_to_add)
      puts key_file
      line = Cocaine::CommandLine.new('ssh-keygen',"-q -t dsa -N '' -f :file", :file => key_file);
      puts line.command
      line.run
      key_path = "/home/#{user_to_add}/.ssh"
      
      rubber.sudo_script 'create_server_user', <<-ENDSCRIPT
        # add the user for running app server with
        if ! id #{user_to_add} &> /dev/null; then useradd -m #{user_to_add}; fi
        mkdir -p #{key_path}
        # add ssh keys for user
        if [[ ! -f /home/#{user_to_add}/.ssh/id_dsa ]]; then ssh-keygen -q -t dsa -N '' -f /home/#{user_to_add}/.ssh/id_dsa; fi
        echo #{user_to_add}:#{user_to_add}123 | chpasswd 
        chage -d 0 #{user_to_add}
      ENDSCRIPT
     upload("#{key_file}.pub","#{key_path}/authorized_keys")
    end

    desc "Delete a user on the server"
    task :delete_server_user do
      set(:user_to_del, Capistrano::CLI.ui.ask("USERNAME you'd like to delete: ") )
      rubber.sudo_script 'delete_server_user', <<-ENDSCRIPT
        if id #{user_to_del}  &> /dev/null; then userdel -f  #{user_to_del}; fi
      ENDSCRIPT
    end