Problem

Bundling libraries is generally recognized as harmful.

As a Gentoo user, I have struggled with properly supporting Netdata on my system for almost as long as Netdata has existed. The upstream installer script and netdata-updater introduce too many conflicts with the way things are supposed to be managed on a source distribution, so I have always preferred using ebuilds for installation.

That entails having to research and compensate for changes in Netdata's build system, disabling features I cannot or do not have the time to properly support in an ebuild, simply holding back my installation at a deprecated version containing known issues because the ebuild needs work, or -- most importantly -- (re)discovering how to dereference one of the libraries Netdata bundles (because this keeps changing in frustrating ways). Our distribution philosophy does not allow packages to bundle libraries for which a proper package already exists, and we must avoid multiple copies of a library on the system; one obvious example of this is libbpf.

The area currently in the most transitional state seems to be the eBPF plugin. A proper source build against system libraries required independently checking out all three of the netdata, kernel-collector, and ebpf-co-re repositories while depending on the system to provide a dev-libs/libbpf[static] dependency. Patches were applied to prevent the build system compiling libbpf itself and use system includes. It made the ebuild significantly more bespoke and less maintainable, but it worked until Netdata 1.45.5.

If I want to use the eBPF plugin (in Gentoo, this would be decided by the USE environment variable containing the string bpf when the ebuild looks for it), I must now attempt to understand the changes made to CMakeLists.txt since then, and understand the topological changes pertaining to how libbpf is bundled, and contrive a maintainable patch set that will conveniently unbundle it and replace it with my system's library, and then I get to find out whether Netdata itself will tolerate the difference. Every update to Netdata entails the risk that this kind of work might have to be done because of the bundled libraries.

Such a state of affairs prevents me from meaningfully contributing to the maintenance of the distribution package in a timely fashion; sometimes I can do this faster or better than the official maintainer, but this time I cannot.

Description

CMakeLists.txt already contains build flags such as ENABLE_BUNDLED_JSONC, ENABLE_BUNDLED_YAML, and ENABLE_BUNDLED_PROTOBUF. A similar boolean flag that falls back on the system library when falsy, e.g. ENABLE_BUNDLED_LIBBPF, is all that would be needed to obviate heaps of work and difficult-to-maintain patchsets that slow down or prevent releases on Gentoo.

Netdata should not rely on any changes to its bundled copy of libbpf that have not been upstreamed. If upstream would not accept them, then they don't belong in that library.

Importance

must have

Value proposition

1. Complete feature support and timely release tracking in official Gentoo distribution packages for Netdata, whereas users of the Gentoo distribution currently have no perfect solution.

Proposed implementation

Consider a modular build flag as described above.