From c89dd4a92f1ece6d022c8c9439771b7dd0ec3923 Mon Sep 17 00:00:00 2001
From: Andre Marianiello <andremarianiello@users.noreply.github.com>
Date: Mon, 5 Feb 2024 11:48:29 -0800
Subject: [PATCH] Use tmpfs mounts when creating a memory-backed emptyDir
 volume

Signed-off-by: Andre Marianiello <andremarianiello@users.noreply.github.com>
---
 pkg/specgen/generate/kube/kube.go        |  7 +++++++
 pkg/specgen/generate/kube/volume.go      | 13 ++++++++++++-
 pkg/specgen/generate/kube/volume_test.go | 24 ++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 pkg/specgen/generate/kube/volume_test.go

diff --git a/pkg/specgen/generate/kube/kube.go b/pkg/specgen/generate/kube/kube.go
index c9361380a9..1ab7eb74e6 100644
--- a/pkg/specgen/generate/kube/kube.go
+++ b/pkg/specgen/generate/kube/kube.go
@@ -554,6 +554,13 @@ func ToSpecGen(ctx context.Context, opts *CtrSpecGenOptions) (*specgen.SpecGener
 				SubPath:     volume.SubPath,
 			}
 			s.Volumes = append(s.Volumes, &emptyDirVolume)
+		case KubeVolumeTypeEmptyDirTmpfs:
+			memVolume := spec.Mount{
+				Destination: volume.MountPath,
+				Type:        define.TypeTmpfs,
+				Source:      define.TypeTmpfs,
+			}
+			s.Mounts = append(s.Mounts, memVolume)
 		default:
 			return nil, errors.New("unsupported volume source type")
 		}
diff --git a/pkg/specgen/generate/kube/volume.go b/pkg/specgen/generate/kube/volume.go
index 48f9abe094..7e86c618cf 100644
--- a/pkg/specgen/generate/kube/volume.go
+++ b/pkg/specgen/generate/kube/volume.go
@@ -34,6 +34,7 @@ const (
 	KubeVolumeTypeCharDevice
 	KubeVolumeTypeSecret
 	KubeVolumeTypeEmptyDir
+	KubeVolumeTypeEmptyDirTmpfs
 )
 
 //nolint:revive
@@ -263,7 +264,17 @@ func VolumeFromConfigMap(configMapVolumeSource *v1.ConfigMapVolumeSource, config
 
 // Create a kubeVolume for an emptyDir volume
 func VolumeFromEmptyDir(emptyDirVolumeSource *v1.EmptyDirVolumeSource, name string) (*KubeVolume, error) {
-	return &KubeVolume{Type: KubeVolumeTypeEmptyDir, Source: name}, nil
+	if emptyDirVolumeSource.Medium == v1.StorageMediumMemory {
+		return &KubeVolume{
+			Type:   KubeVolumeTypeEmptyDirTmpfs,
+			Source: name,
+		}, nil
+	} else {
+		return &KubeVolume{
+			Type:   KubeVolumeTypeEmptyDir,
+			Source: name,
+		}, nil
+	}
 }
 
 // Create a KubeVolume from one of the supported VolumeSource
diff --git a/pkg/specgen/generate/kube/volume_test.go b/pkg/specgen/generate/kube/volume_test.go
new file mode 100644
index 0000000000..aa7548c46a
--- /dev/null
+++ b/pkg/specgen/generate/kube/volume_test.go
@@ -0,0 +1,24 @@
+//go:build !remote
+
+package kube
+
+import (
+	"testing"
+
+	v1 "github.com/containers/podman/v4/pkg/k8s.io/api/core/v1"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestVolumeFromEmptyDir(t *testing.T) {
+	emptyDirSource := v1.EmptyDirVolumeSource{}
+	emptyDirVol, err := VolumeFromEmptyDir(&emptyDirSource, "emptydir")
+	assert.NoError(t, err)
+	assert.Equal(t, emptyDirVol.Type, KubeVolumeTypeEmptyDir)
+
+	memEmptyDirSource := v1.EmptyDirVolumeSource{
+		Medium: v1.StorageMediumMemory,
+	}
+	memEmptyDirVol, err := VolumeFromEmptyDir(&memEmptyDirSource, "emptydir")
+	assert.NoError(t, err)
+	assert.Equal(t, memEmptyDirVol.Type, KubeVolumeTypeEmptyDirTmpfs)
+}