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.
Convert resource templates from json to yaml
Yaml is easier and less error prone to modify by hand. It also allows
comments which can be especially useful in the templates.
Counting nodes in Ready state was too fragile, matching
entries like:
Ready,SchedulingDisabled
NotReady
By requiring whitespace on both side, we accept only clean Ready.
A "newbie style" deployment attempt was made on a recent
cluster, and some added notes in README and in label-nodes.sh
could help someone who just started with node-feature-discovery.
Correcting also description of label-nodes.sh which does not
deal with unlabeled nodes as was promised in README.
