feat(platform): add node orchestration and the felis entrypoint

The platform package that places servers across nodes and wires the operator, build, restore, and reaper subsystems, plus cmd/felis, the single binary that runs them.

cmd/felis/operator.go

@@ -0,0 +1,75 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+
+	"felis.lolicon.best/internal/apis/felis/v1alpha1"
+	"felis.lolicon.best/internal/operator"
+	"k8s.io/apimachinery/pkg/runtime"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/cache"
+	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"
+)
+
+// cmdOperator runs the MinecraftServer controller-manager (spec §5). It builds
+// the scheme, wires the Reconciler with the production RCON prober, and blocks
+// on the manager until the process receives a termination signal.
+func cmdOperator(args []string, _, stderr io.Writer) int {
+	fs := flag.NewFlagSet("operator", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	metricsAddr := fs.String("metrics-bind-address", ":8080", "address the metric endpoint binds to")
+	// namespace MUST equal the [k8s] namespace felis-api is configured with, and
+	// the deployment manifests (felis manifests) render both from one value. It
+	// scopes the manager's cache (informers) to a single namespace so the operator
+	// can run under a namespaced Role instead of cluster-admin (spec §21). The
+	// default matches config.defaultNamespace, so an unconfigured deployment
+	// agrees; a mismatch would silently scope the cache to the wrong namespace and
+	// every reconcile would see zero servers — hence the watched namespace is
+	// logged at startup so a divergence surfaces immediately rather than silently.
+	namespace := fs.String("namespace", "minecraft", "namespace to watch; must match felis-api's [k8s] namespace")
+	if err := fs.Parse(args); err != nil {
+		return 2
+	}
+
+	scheme := runtime.NewScheme()
+	utilruntime.Must(clientgoscheme.AddToScheme(scheme))
+	utilruntime.Must(v1alpha1.AddToScheme(scheme))
+
+	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
+		Scheme:  scheme,
+		Metrics: metricsserver.Options{BindAddress: *metricsAddr},
+		// Scope every informer to the single watched namespace. Without this the
+		// cached client (mgr.GetClient) would LIST/WATCH cluster-wide, which a
+		// namespaced Role cannot grant — the operator would fail closed at runtime
+		// or, worse, demand cluster-admin. With it, the platform.OperatorRole
+		// (get/list/watch in one namespace) is exactly sufficient.
+		Cache: cache.Options{
+			DefaultNamespaces: map[string]cache.Config{*namespace: {}},
+		},
+	})
+	if err != nil {
+		fmt.Fprintf(stderr, "felis operator: create manager: %v\n", err)
+		return 1
+	}
+	fmt.Fprintf(stderr, "felis operator: watching namespace %q\n", *namespace)
+
+	r := &operator.Reconciler{
+		Client: mgr.GetClient(),
+		Scheme: mgr.GetScheme(),
+		Prober: operator.RconProber{},
+	}
+	if err := r.SetupWithManager(mgr); err != nil {
+		fmt.Fprintf(stderr, "felis operator: setup controller: %v\n", err)
+		return 1
+	}
+
+	if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
+		fmt.Fprintf(stderr, "felis operator: manager exited: %v\n", err)
+		return 1
+	}
+	return 0
+}