Fix handling of installation prefix so that we don’t use /usr under the prefix.

[Ferroin]

Summary

If installing to a prefix, we should not be using /usr inside that prefix. Doing so causes all kinds of problems and makes things behave in ways users do not expect them to.

Test Plan

This needs verification for both installs and updates on a variety of systems.

Additional Information

Fixes: #13242

This requires special handling around the merge as it is technically a breaking change.

[Dim-P]

Should this:

netdata/netdata-installer.sh

Lines 914 to 915 in 5319b43

	if [ -x "${NETDATA_PREFIX}/usr/libexec/netdata-switch-dashboard.sh" ]; then
	"${NETDATA_PREFIX}/usr/libexec/netdata-switch-dashboard.sh" classic

and also this:

netdata/netdata-installer.sh

Lines 1456 to 1458 in 5319b43

	if [ -f "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/go.d.plugin" ]; then
	if command -v setcap 1>/dev/null 2>&1; then
	run setcap "cap_net_admin+epi cap_net_raw=eip" "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/go.d.plugin"

be changed to NETDATA_LIBEXECDIR as well?

It generally works OK so far, but I want to do some more testing before approving it.

[Ferroin]

Should this:

netdata/netdata-installer.sh

Lines 914 to 915 in 5319b43

	if [ -x "${NETDATA_PREFIX}/usr/libexec/netdata-switch-dashboard.sh" ]; then
	"${NETDATA_PREFIX}/usr/libexec/netdata-switch-dashboard.sh" classic

and also this:

netdata/netdata-installer.sh

Lines 1456 to 1458 in 5319b43

	if [ -f "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/go.d.plugin" ]; then
	if command -v setcap 1>/dev/null 2>&1; then
	run setcap "cap_net_admin+epi cap_net_raw=eip" "${NETDATA_PREFIX}/usr/libexec/netdata/plugins.d/go.d.plugin"

be changed to NETDATA_LIBEXECDIR as well?

The first case needs to stay as-is (it’s there as a compatibility hack, though it can probably be removed at some point in the near future).

The second case does actually need updated though, not sure how I missed it.

[Ferroin]

Rebased to pick up CI changes.

[Ferroin]

Converting this to a draft because it still needs more work.

[Dim-P]

@Ferroin How are you planning to handle existing installs?

[Ferroin]

@Ferroin How are you planning to handle existing installs?

Handling of that is part of the reason this got switched to be a draft again. I’m trying to come up with a good solution for preserving the existing paths there (and ideally also a migration path for static installs, but that will probably be a separate PR from this one).

[Ferroin]

Rebased to pick up CI fixes.

[Ferroin]

Rebased to resolve merge conflicts.

[Ferroin]

Closing in favor of #17308