10. What is sc_pack?

sc_pack is a “pack” of programs that helps manage edge servers running ShimmerCat Accelerator. It includes and configures the following programs:

  • ShimmerCat QS: the program actually serving files

  • sc_logsagent: a small program that sends ShimmerCat’s logs to the mothership (our cloud service)

  • redis: used by ShimmerCat, and usually included right with it

  • supervisord: A utility that helps manage stacks of programs

  • A Celery worker, that takes instructions from the cloud service.

  • An update daemon, that can upon instructions download a new version of sc_pack and install it.

  • An image optimization service (usher) that, when enabled, submits image optimization jobs to our cloud service.

  • Several utilities for synchronizing the configuration of a site across multiple deployment sites.

10.1. How everything runs

You can understand more easily what’s going on if you compare the programs in this list to a well-coordinated sports team whose captain is supervisord, while sc-pack itself is its coach or manager.

In Unix, each process has a parent, and here is how it looks for sc_pack:

   <system process manager>
     -- sc_pack's supervisord
           -- redis-server
           -- sc_logs_agent
           -- shimmercat
           -- celery worker
     -- sc_pack's update

To learn more about how to setup your sc_pack configuration, see setup sc_pack

10.2. Install sc_pack

To install sc_pack, please see the information on Install sc_pack.