Crowbar is a self-referential barclamp used for enabling other barclamps. By creating a Crowbar proposal, you can modify the default number of threads and workers. This way, you can scale the admin server according to the actual usage or the number of available cores of the admin node.

Figure 16.1: The Crowbar barclamp: Raw Mode #

To change the default settings, create a Crowbar proposal and switch to the Raw view. Adjust then the workers and threads values. The number of threads should be set to the number of available cores. The default number of workers should be increased to 3 if the graphical interface becomes slow. Save and apply the changes using the appropriate buttons.

The NTP service is responsible for keeping the clocks in your cloud servers in sync. Among other things, synchronized clocks ensure that the chef-client works properly. It also makes it easier to read logs from different nodes by correlating timestamps in them. The NTP component is deployed on the Administration Server automatically using the default settings. The NTP barclamp can be used to specify IP addresses of the external NTP servers and assign specific roles to the desired nodes. The following parameter can be configured using the NTP barclamp:

The NTP service consists of two different roles: