conf: add a new default node selector config variable

This configuration variable can be used by an admin or developer
deploying the operator to change the default node selector values.
If specified, this configuration variable is expected to contain a JSON
map.

Signed-off-by: John Mulligan <[email protected]>

Author: phlogistonjohn

internal/conf/config.go

@@ -24,6 +24,7 @@ var DefaultOperatorConfig = OperatorConfig{
 	SmbdPort:                  445,
 	MetricsExporterMode:       "disabled",
 	ImagePullPolicy:           "IfNotPresent",
+	DefaultNodeSelector:       "",
 }
 
 // OperatorConfig is a type holding general configuration values.
@@ -78,6 +79,10 @@ type OperatorConfig struct {
 	// ImagePullPolicy is a (string) value which defines the image-download
 	// strategy of samba containers.
 	ImagePullPolicy string `mapstructure:"image-pull-policy"`
+	// DefaultNodeSelector is a string value containing JSON which defines
+	// a set of key-value pairs that will be used for all default node
+	// selection. If left blank, internal defaults will be used.
+	DefaultNodeSelector string `mapstructure:"default-node-selector"`
 }
 
 // Validate the OperatorConfig returning an error if the config is not
@@ -128,6 +133,7 @@ func NewSource() *Source {
 	v.SetDefault("pod-namespace", d.PodNamespace)
 	v.SetDefault("pod-ip", d.PodIP)
 	v.SetDefault("image-pull-policy", d.ImagePullPolicy)
+	v.SetDefault("default-node-selector", d.DefaultNodeSelector)
 	return &Source{v: v}
 }