play kube: set defaults to container resources

this fixes https://github.com/containers/podman/issues/13115

the change tries to immitate k8s behavior.
when limits are not set the container's limits are all CPU and all RAM
when requests are missing then they are equal to limits

Signed-off-by: Yaron Dayagi <ydayagi@redhat.com>

2 files changed, 126 insertions, 1 deletions

diff --git a/pkg/specgen/generate/kube/kube.go b/pkg/specgen/generate/kube/kube.go
index 475401016..a8f17e2b6 100644
--- a/pkg/specgen/generate/kube/kube.go
+++ b/pkg/specgen/generate/kube/kube.go
@@ -7,6 +7,7 @@ import (
 	"math"
 	"net"
 	"regexp"
+	"runtime"
 	"strconv"
 	"strings"
 	"time"
@@ -22,6 +23,7 @@ import (
 	"github.com/containers/podman/v4/pkg/specgen"
 	"github.com/containers/podman/v4/pkg/specgen/generate"
 	"github.com/containers/podman/v4/pkg/util"
+	"github.com/docker/docker/pkg/system"
 	"github.com/docker/go-units"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
@@ -700,8 +702,12 @@ func envVarValueResourceFieldRef(env v1.EnvVar, opts *CtrSpecGenOptions) (*strin
 		divisor.Set(1)
 	}
 
+	resources, err := getContainerResources(opts.Container)
+	if err != nil {
+		return nil, err
+	}
+
 	var value *resource.Quantity
-	resources := opts.Container.Resources
 	resourceName := env.ValueFrom.ResourceFieldRef.Resource
 	var isValidDivisor bool
 
@@ -757,6 +763,46 @@ func isCPUDivisor(divisor resource.Quantity) bool {
 	}
 }
 
+func getContainerResources(container v1.Container) (v1.ResourceRequirements, error) {
+	result := v1.ResourceRequirements{
+		Limits:   v1.ResourceList{},
+		Requests: v1.ResourceList{},
+	}
+
+	limits := container.Resources.Limits
+	requests := container.Resources.Requests
+
+	if limits == nil || limits.Memory().IsZero() {
+		mi, err := system.ReadMemInfo()
+		if err != nil {
+			return result, err
+		}
+		result.Limits[v1.ResourceMemory] = *resource.NewQuantity(mi.MemTotal, resource.DecimalSI)
+	} else {
+		result.Limits[v1.ResourceMemory] = limits[v1.ResourceMemory]
+	}
+
+	if limits == nil || limits.Cpu().IsZero() {
+		result.Limits[v1.ResourceCPU] = *resource.NewQuantity(int64(runtime.NumCPU()), resource.DecimalSI)
+	} else {
+		result.Limits[v1.ResourceCPU] = limits[v1.ResourceCPU]
+	}
+
+	if requests == nil || requests.Memory().IsZero() {
+		result.Requests[v1.ResourceMemory] = result.Limits[v1.ResourceMemory]
+	} else {
+		result.Requests[v1.ResourceMemory] = requests[v1.ResourceMemory]
+	}
+
+	if requests == nil || requests.Cpu().IsZero() {
+		result.Requests[v1.ResourceCPU] = result.Limits[v1.ResourceCPU]
+	} else {
+		result.Requests[v1.ResourceCPU] = requests[v1.ResourceCPU]
+	}
+
+	return result, nil
+}
+
 // getPodPorts converts a slice of kube container descriptions to an
 // array of portmapping
 func getPodPorts(containers []v1.Container) []types.PortMapping {
diff --git a/pkg/specgen/generate/kube/play_test.go b/pkg/specgen/generate/kube/play_test.go
index 282324310..6798fdb1b 100644
--- a/pkg/specgen/generate/kube/play_test.go
+++ b/pkg/specgen/generate/kube/play_test.go
@@ -6,10 +6,12 @@ import (
 	"io/ioutil"
 	"math"
 	"os"
+	"runtime"
 	"strconv"
 	"testing"
 
 	"github.com/containers/common/pkg/secrets"
+	"github.com/docker/docker/pkg/system"
 	"github.com/stretchr/testify/assert"
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
@@ -193,6 +195,11 @@ func TestEnvVarValue(t *testing.T) {
 	assert.NoError(t, err)
 	defer os.RemoveAll(d)
 	secretsManager := createSecrets(t, d)
+	stringNumCPUs := strconv.Itoa(runtime.NumCPU())
+
+	mi, err := system.ReadMemInfo()
+	assert.Nil(t, err)
+	stringMemTotal := strconv.FormatInt(mi.MemTotal, 10)
 
 	tests := []struct {
 		name     string
@@ -694,6 +701,78 @@ func TestEnvVarValue(t *testing.T) {
 			true,
 			strconv.Itoa(int(float64(cpuInt) / 0.001)),
 		},
+		{
+			"ResourceFieldRefNoLimitMemory",
+			v1.EnvVar{
+				Name: "FOO",
+				ValueFrom: &v1.EnvVarSource{
+					ResourceFieldRef: &v1.ResourceFieldSelector{
+						Resource: "limits.memory",
+					},
+				},
+			},
+			CtrSpecGenOptions{
+				Container: v1.Container{
+					Name: "test",
+				},
+			},
+			true,
+			stringMemTotal,
+		},
+		{
+			"ResourceFieldRefNoRequestMemory",
+			v1.EnvVar{
+				Name: "FOO",
+				ValueFrom: &v1.EnvVarSource{
+					ResourceFieldRef: &v1.ResourceFieldSelector{
+						Resource: "requests.memory",
+					},
+				},
+			},
+			CtrSpecGenOptions{
+				Container: v1.Container{
+					Name: "test",
+				},
+			},
+			true,
+			stringMemTotal,
+		},
+		{
+			"ResourceFieldRefNoLimitCPU",
+			v1.EnvVar{
+				Name: "FOO",
+				ValueFrom: &v1.EnvVarSource{
+					ResourceFieldRef: &v1.ResourceFieldSelector{
+						Resource: "limits.cpu",
+					},
+				},
+			},
+			CtrSpecGenOptions{
+				Container: v1.Container{
+					Name: "test",
+				},
+			},
+			true,
+			stringNumCPUs,
+		},
+		{
+			"ResourceFieldRefNoRequestCPU",
+			v1.EnvVar{
+				Name: "FOO",
+				ValueFrom: &v1.EnvVarSource{
+					ResourceFieldRef: &v1.ResourceFieldSelector{
+						Resource: "requests.cpu",
+					},
+				},
+			},
+			CtrSpecGenOptions{
+				Container: v1.Container{
+					Name: "test",
+				},
+			},
+			true,
+			stringNumCPUs,
+		},
 	}
 
 	for _, test := range tests {