Flatten the data structure that stores features, dropping the "domain"
level from the data model. That extra level of hierarchy brought little
benefit but just caused some extra complexity, instead. The new
structure nicely matches what we have in the NodeFeatureRule object (the
matchFeatures field of uses the same flat structure with the "feature"
field having a value <domain>.<feature>, e.g. "kernel.version").
This is pre-work for introducing a new "node feature" CRD that contains
the raw feature data. It makes the life of both users and developers
easier when both CRDs, plus our internal code, handle feature data in a
similar flat structure.
Move the previously-protobuf-only internal "feature api" over to the
public "nfd api" package. This is in preparation for introducing a new
CRD API for communicating features.
This patch carries no functional changes. Just moving code around.
Enable transmitting the discovered "raw" features over the gRPC API.
Extend pkg/api/feature with protobuf and gRPC code. In this, utilize
go-to-protobuf from k8s code-generator for auto-generating the gRPC
interface from golang code. The tool can be Installed with:
go install k8s.io/code-generator/cmd/go-to-protobuf@v0.20.7
The auto-generated code is (re-)generated/updated with "make apigen".
Use 'go generate' for auto-generating code. Drop the old 'mock' and
'apigen' makefile targets. Those are replaced with a single
make generate
which (re-)generates everything.
For auto-generating api(s).
Also, re-generate/refresh the gRPC with `make apigen` (with protoc
v3.17.3 and protoc-gen-go from github.com/golang/protobuf v1.5.2) to
sync up things.
Extend the FeatureSource interface with new methods for configuration
handling. This enables easier on-the fly reconfiguration of the
feature sources. Further, it simplifies adding config support to feature
sources in the future. Stub methods are added to sources that do not
currently have any configurability.
The patch fixes some (corner) cases with the overrides (--options)
handling, too:
- Overrides were not applied if config file was missing or its parsing
failed
- Overrides for a certain source did not have effect if an empty config
for the source was specified in the config file. This was caused by
the first pass of parsing (config file) setting a nil pointer to the
source-specific config, effectively detaching it from the main config.
The second pass would then create a new instance of the source
specific config, but, this was not visible in the feature source, of
course.
Refactor NFD into a simple server-client system. Labeling is now done by
a separate 'nfd-master' server. It is a simple service with small
codebase, designed for easy isolation. The feature discovery part is
implemented in a 'nfd-worker' client which sends labeling requests to
nfd-server, thus, requiring no access/permissions to the Kubernetes API
itself.
Client-server communication is implemented by using gRPC. The protocol
currently consists of only one request, i.e. the labeling request.
The spec templates are converted to the new scheme. The nfd-master
server can be deployed using the nfd-master.yaml.template which now also
contains the necessary RBAC configuration. NFD workers can be deployed
by using the nfd-worker-daemonset.yaml.template or
nfd-worker-job.yaml.template (most easily used with the label-nodes.sh
script).
Only nfd-worker currently support config file or options. The (default)
NFD config file is renamed to nfd-worker.conf.
