diff --git a/lib/resourcebuilder/podspec.go b/lib/resourcebuilder/podspec.go
index b4b4fa83e5..80d854f062 100644
--- a/lib/resourcebuilder/podspec.go
+++ b/lib/resourcebuilder/podspec.go
@@ -2,6 +2,7 @@ package resourcebuilder
 
 import (
 	"fmt"
+	"strings"
 
 	corev1 "k8s.io/api/core/v1"
 )
@@ -10,9 +11,8 @@ import (
 // matching the container names.
 func updatePodSpecWithProxy(podSpec *corev1.PodSpec, containerNames []string, httpProxy, httpsProxy, noProxy string) error {
 	hasProxy := len(httpsProxy) > 0 || len(httpProxy) > 0 || len(noProxy) > 0
-	if !hasProxy {
-		return nil
-	}
+
+	var notFoundContainerNames []string
 
 	for _, containerName := range containerNames {
 		found := false
@@ -22,9 +22,11 @@ func updatePodSpecWithProxy(podSpec *corev1.PodSpec, containerNames []string, ht
 			}
 			found = true
 
-			podSpec.Containers[i].Env = append(podSpec.Containers[i].Env, corev1.EnvVar{Name: "HTTP_PROXY", Value: httpProxy})
-			podSpec.Containers[i].Env = append(podSpec.Containers[i].Env, corev1.EnvVar{Name: "HTTPS_PROXY", Value: httpsProxy})
-			podSpec.Containers[i].Env = append(podSpec.Containers[i].Env, corev1.EnvVar{Name: "NO_PROXY", Value: noProxy})
+			if hasProxy {
+				podSpec.Containers[i].Env = append(podSpec.Containers[i].Env, corev1.EnvVar{Name: "HTTP_PROXY", Value: httpProxy})
+				podSpec.Containers[i].Env = append(podSpec.Containers[i].Env, corev1.EnvVar{Name: "HTTPS_PROXY", Value: httpsProxy})
+				podSpec.Containers[i].Env = append(podSpec.Containers[i].Env, corev1.EnvVar{Name: "NO_PROXY", Value: noProxy})
+			}
 		}
 		for i := range podSpec.InitContainers {
 			if podSpec.InitContainers[i].Name != containerName {
@@ -32,16 +34,22 @@ func updatePodSpecWithProxy(podSpec *corev1.PodSpec, containerNames []string, ht
 			}
 			found = true
 
-			podSpec.InitContainers[i].Env = append(podSpec.InitContainers[i].Env, corev1.EnvVar{Name: "HTTP_PROXY", Value: httpProxy})
-			podSpec.InitContainers[i].Env = append(podSpec.InitContainers[i].Env, corev1.EnvVar{Name: "HTTPS_PROXY", Value: httpsProxy})
-			podSpec.InitContainers[i].Env = append(podSpec.InitContainers[i].Env, corev1.EnvVar{Name: "NO_PROXY", Value: noProxy})
+			if hasProxy {
+				podSpec.InitContainers[i].Env = append(podSpec.InitContainers[i].Env, corev1.EnvVar{Name: "HTTP_PROXY", Value: httpProxy})
+				podSpec.InitContainers[i].Env = append(podSpec.InitContainers[i].Env, corev1.EnvVar{Name: "HTTPS_PROXY", Value: httpsProxy})
+				podSpec.InitContainers[i].Env = append(podSpec.InitContainers[i].Env, corev1.EnvVar{Name: "NO_PROXY", Value: noProxy})
+			}
 		}
 
 		if !found {
-			return fmt.Errorf("requested injection for non-existent container: %q", containerName)
+			notFoundContainerNames = append(notFoundContainerNames, containerName)
 		}
 	}
 
+	if len(notFoundContainerNames) > 0 {
+		return fmt.Errorf("requested injection for non-existent containers: %s", strings.Join(notFoundContainerNames, ", "))
+	}
+
 	return nil
 
 }
diff --git a/lib/resourcebuilder/podspec_test.go b/lib/resourcebuilder/podspec_test.go
index 248c05c488..37a5c19bd9 100644
--- a/lib/resourcebuilder/podspec_test.go
+++ b/lib/resourcebuilder/podspec_test.go
@@ -89,6 +89,49 @@ func TestUpdatePodSpecWithProxy(t *testing.T) {
 				},
 			},
 		},
+		{
+			name:           "proxy info, invalid container name",
+			containerNames: []string{"foo", "invalid"},
+			httpsProxy:     "httpsProxy-val",
+			noProxy:        "noProxy-val",
+			input: &corev1.PodSpec{
+				InitContainers: []corev1.Container{
+					{Name: "init-foo"},
+				},
+				Containers: []corev1.Container{
+					{Name: "foo"},
+				},
+			},
+			expectedErr: "requested injection for non-existent containers: invalid",
+		},
+		{
+			name:           "no proxy info, invalid container name",
+			containerNames: []string{"foo", "invalid"},
+			input: &corev1.PodSpec{
+				InitContainers: []corev1.Container{
+					{Name: "init-foo"},
+				},
+				Containers: []corev1.Container{
+					{Name: "foo"},
+				},
+			},
+			expectedErr: "requested injection for non-existent containers: invalid",
+		},
+		{
+			name:           "proxy info, multiple invalid container names",
+			containerNames: []string{"foo", "invalid1", "invalid2"},
+			httpsProxy:     "httpsProxy-val",
+			noProxy:        "noProxy-val",
+			input: &corev1.PodSpec{
+				InitContainers: []corev1.Container{
+					{Name: "init-foo"},
+				},
+				Containers: []corev1.Container{
+					{Name: "foo"},
+				},
+			},
+			expectedErr: "requested injection for non-existent containers: invalid1, invalid2",
+		},
 	}
 
 	for _, test := range tests {
@@ -104,7 +147,7 @@ func TestUpdatePodSpecWithProxy(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			if !reflect.DeepEqual(test.input, test.expected) {
+			if test.expectedErr == "" && !reflect.DeepEqual(test.input, test.expected) {
 				t.Error(cmp.Diff(test.input, test.expected))
 			}
 		})