code: def activate_host(self, host):
          '''
          Flag a host as active.
          '''
  
          logger.debug('Activating host: {0}'.format(host))
  
          # Add to *both* activated and active - active will reduce as hosts fail
          # but connected will not, enabling us to track failed %.
          self.activated_hosts.add(host)
          self.active_hosts.add(hostf activate_host(self, host):
          '''
          Flag a host as active.
          '''
  
          logger.debug('Activating host: {0}'.format(host))
  
          # Add to *both* activated and active - active will reduce as hosts fail
          # but connected will not, enabling us to track failed %.
          self.activated_hosts.add(host)
          self.active_hosts.add(host)
docs: Flag a host as active.