PCP is a capable and expansive framework for system performance and
Marius and Andreas have done some really nice work using PCP for metrics
and loading of archived metric data.
However in order to make use if it, attention to and grooming of PCP is
necessary. Details below.
A bunch of us discussed this yesterday, and came to the conclusion that
having PCP required by default goes against the principles  of
Cockpit. In particular:
* Cockpit should work out of the box. In particular the graphs should
work out of the box.
* Installing Cockpit should not fundamentally alter the server, via
dependencies, additional running services ... and the footprint
should be small.
Cockpit isn't perfect on the latter point yet. We do drag in runtime
dependencies that should be optional (such as accountsservice and
realmd), but with each release we're removing those. The end goal is
that Cockpit is a UI for the OS, and the software that comes with it.
Yes, I do realize this is a fuzzy goal, but never the less, we want to
be heading in the right direction.
Outstanding PCP issues:
None of these issues are unsolvable. In fact during brainstorming and
discussion with Frank and the PCP team there have been possible
solutions to each of the issues.
Once the outstanding issues have been resolved, it would be probably be
appropriate for Cockpit to have a default dependency on pcp-libs and the
But it is premature for us to have a PCP dependency out of the box, and
doubly so when that dependency is on the entire PCP stack.
So we're doing a bit of work to make PCP optional:
On Fedora 22, folks who want to use PCP and view archived data in the
graphs, or folks who already have PCP on their server, will be able to
install the optional cockpit-pcp sub-package.