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.
Implement new 'system' feature source. It now detects OS release
information from the os-release file, assumed to be available at
/host-etc/os-release. It currently creates two labels (assuming that the
corresponding fields are found in the os-release file), with example
values:
feature.node.kubernetes.io/system-os_release.ID=opensuse
feature.node.kubernetes.io/system-os_release.VERSION_ID=42.3
Also, update the template spec to mount /etc/os-release file from the
host inside the container.
This implementation only detects kconfig options ("NO_HZ", "NO_HZ_IDLE",
"NO_HZ_FULL" and "PREEMPT"). The corresponding node labels will be
node.alpha.kubernetes-incubator.io/nfd-kernel-config.<option name>
Currently, only bool and tristate (i.e. '=y' or '=m') kernel config
options are supported. Other kconfig types (e.g. string or int) are
simply ignored. If the kconfig flag is set to '=y' or '=m', the
corresponding node label will be present and it's value will be 'true'.
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.
