feat: check for available node resources before building injector pod (…

…#2220)

## Description

Addresses #2144 to check
if node has enough resources before the injector runs

## Related Issue

Fixes #2144 

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Other (security config, docs update, etc)

## Checklist before merging

- [x] Test, docs, adr added or updated as needed
- [x] [Contributor Guide
Steps](https://github.com/defenseunicorns/zarf/blob/main/CONTRIBUTING.md#developer-workflow)
followed

---------

Co-authored-by: Wayne Starr <[email protected]>

src/pkg/cluster/injector.go

@@ -28,6 +28,13 @@ import (
 // The chunk size for the tarball chunks.
 var payloadChunkSize = 1024 * 768
 
+var (
+	injectorRequestedCPU    = resource.MustParse(".5")
+	injectorRequestedMemory = resource.MustParse("64Mi")
+	injectorLimitCPU        = resource.MustParse("1")
+	injectorLimitMemory     = resource.MustParse("256Mi")
+)
+
 // StartInjectionMadness initializes a Zarf injection into the cluster.
 func (c *Cluster) StartInjectionMadness(tmpDir string, imagesDir string, injectorSeedSrcs []string) {
 	spinner := message.NewProgressSpinner("Attempting to bootstrap the seed image into the cluster")
@@ -54,7 +61,7 @@ func (c *Cluster) StartInjectionMadness(tmpDir string, imagesDir string, injecto
 	// Get all the images from the cluster
 	timeout := 5 * time.Minute
 	spinner.Updatef("Getting the list of existing cluster images (%s timeout)", timeout.String())
-	if images, err = c.GetAllImages(timeout); err != nil {
+	if images, err = c.GetAllImages(timeout, injectorRequestedCPU, injectorRequestedMemory); err != nil {
 		spinner.Fatalf(err, "Unable to generate a list of candidate images to perform the registry injection")
 	}
 
@@ -362,12 +369,12 @@ func (c *Cluster) buildInjectionPod(node, image string, payloadConfigmaps []stri
 			// Keep resources as light as possible as we aren't actually running the container's other binaries
 			Resources: corev1.ResourceRequirements{
 				Requests: corev1.ResourceList{
-					corev1.ResourceCPU:    resource.MustParse(".5"),
-					corev1.ResourceMemory: resource.MustParse("64Mi"),
+					corev1.ResourceCPU:    injectorRequestedCPU,
+					corev1.ResourceMemory: injectorRequestedMemory,
 				},
 				Limits: corev1.ResourceList{
-					corev1.ResourceCPU:    resource.MustParse("1"),
-					corev1.ResourceMemory: resource.MustParse("256Mi"),
+					corev1.ResourceCPU:	   injectorLimitCPU,
+					corev1.ResourceMemory: injectorLimitMemory,
 				},
 			},
 		},

src/pkg/k8s/images.go

@@ -9,6 +9,7 @@ import (
 	"sort"
 	"time"
 
+	"k8s.io/apimachinery/pkg/api/resource"
 	corev1 "k8s.io/api/core/v1"
 )
 
@@ -19,7 +20,7 @@ type ImageMap map[string]bool
 type ImageNodeMap map[string][]string
 
 // GetAllImages returns a list of images and their nodes found in pods in the cluster.
-func (k *K8s) GetAllImages(timeoutDuration time.Duration) (ImageNodeMap, error) {
+func (k *K8s) GetAllImages(timeoutDuration time.Duration, minNodeCPU resource.Quantity, minNodeMemory resource.Quantity) (ImageNodeMap, error) {
 	timeout := time.After(timeoutDuration)
 
 	for {
@@ -34,7 +35,7 @@ func (k *K8s) GetAllImages(timeoutDuration time.Duration) (ImageNodeMap, error)
 		// After delay, try running.
 		default:
 			// If no images or an error, log and loop.
-			if images, err := k.GetImagesWithNodes(corev1.NamespaceAll); len(images) < 1 || err != nil {
+			if images, err := k.GetImagesWithNodes(corev1.NamespaceAll, minNodeCPU, minNodeMemory); len(images) < 1 || err != nil {
 				k.Log("no images found: %w", err)
 			} else {
 				// Otherwise, return the image list.
@@ -46,7 +47,7 @@ func (k *K8s) GetAllImages(timeoutDuration time.Duration) (ImageNodeMap, error)
 
 // GetImagesWithNodes checks for images on schedulable nodes and returns
 // a map of these images and their nodes in a given namespace.
-func (k *K8s) GetImagesWithNodes(namespace string) (ImageNodeMap, error) {
+func (k *K8s) GetImagesWithNodes(namespace string, minNodeCPU resource.Quantity, minNodeMemory resource.Quantity) (ImageNodeMap, error) {
 	result := make(ImageNodeMap)
 
 	pods, err := k.GetPods(namespace)
@@ -68,6 +69,11 @@ findImages:
 			return nil, fmt.Errorf("unable to get the node %s", pod.Spec.NodeName)
 		}
 
+		if nodeDetails.Status.Allocatable.Cpu().Cmp(minNodeCPU) < 0 ||
+		   nodeDetails.Status.Allocatable.Memory().Cmp(minNodeMemory) < 0 {
+			continue findImages
+		}
+
 		for _, taint := range nodeDetails.Spec.Taints {
 			if taint.Effect == corev1.TaintEffectNoSchedule || taint.Effect == corev1.TaintEffectNoExecute {
 				continue findImages