Use FQDN for node name if cloud provider is set to AWS (#1631)

* Use fqdn if cloud provider is set to aws

* fix comments

pkg/rke2/rke2_linux.go

@@ -3,7 +3,9 @@
 package rke2
 
 import (
+	"bytes"
 	"fmt"
+	"os/exec"
 	"path/filepath"
 	"strings"
 
@@ -59,6 +61,15 @@ func initExecutor(clx *cli.Context, cfg Config, dataDir string, disableETCD bool
 			Name: cfg.CloudProviderName,
 			Path: cfg.CloudProviderConfig,
 		}
+		if clx.String("node-name") == "" && cfg.CloudProviderName == "aws" {
+			fqdn, err := hostnameFQDN()
+			if err != nil {
+				return nil, err
+			}
+			if err := clx.Set("node-name", fqdn); err != nil {
+				return nil, err
+			}
+		}
 	}
 
 	if cfg.KubeletPath == "" {
@@ -175,3 +186,16 @@ func initExecutor(clx *cli.Context, cfg Config, dataDir string, disableETCD bool
 		ControlPlaneMounts:    extraMounts,
 	}, nil
 }
+
+func hostnameFQDN() (string, error) {
+	cmd := exec.Command("hostname", "-f")
+
+	var b bytes.Buffer
+	cmd.Stdout = &b
+
+	if err := cmd.Run(); err != nil {
+		return "", err
+	}
+
+	return strings.TrimSpace(b.String()), nil
+}