Run glance-api as privileged container when image cache is enabled

ImageCache currently uses two different cronJobs associated to each
glance-api instance (-cleaner and -pruner cronJobs). They mount
/var/lib/glance/image-cache, a RWO Pvc, and execute a glance utility
on the filestem owned by glance kolla user/group. Without glance-api
being privileged, after the cronJob execution the Glance Pod is not
able to access the image-cache path anymore, resulting in a Permission
denied error.
This patch defines a FSGroup that should be set at Pod level to make
sure we always have the right privileges on the container fs, and,
in addition, it runs glance-api as a privileged container when Cache
is enabled.

Jira: https://issues.redhat.com/browse/OSPRH-9842

Signed-off-by: Francesco Pantano <[email protected]>

controllers/glanceapi_controller.go

@@ -802,6 +802,8 @@ func (r *GlanceAPIReconciler) reconcileNormal(
 
 	// This is currently required because cleaner and pruner cronJobs
 	// mount the same pvc to clean data present in /var/lib/glance/image-cache
+	// TODO (fpantano) reference a Glance spec/proposal to move to a different
+	// approach
 	if len(instance.Spec.ImageCache.Size) > 0 {
 		privileged = true
 	}

pkg/glance/funcs.go

@@ -65,6 +65,7 @@ func BaseSecurityContext() *corev1.SecurityContext {
 func APISecurityContext(userID int64, privileged bool) *corev1.SecurityContext {
 	runAsUser := int64(userID)
 	trueVal := true
+
 	return &corev1.SecurityContext{
 		AllowPrivilegeEscalation: &trueVal,
 		RunAsUser:                &runAsUser,
@@ -77,16 +78,19 @@ func APISecurityContext(userID int64, privileged bool) *corev1.SecurityContext {
 
 // HttpdSecurityContext -
 func HttpdSecurityContext() *corev1.SecurityContext {
-	runAsUser := int64(0)
-	falseVal := false
+	runAsUser := int64(GlanceUID)
+	runAsGroup := int64(GlanceGID)
+	trueVal := true
+
 	return &corev1.SecurityContext{
-		AllowPrivilegeEscalation: &falseVal,
+		AllowPrivilegeEscalation: &trueVal,
 		Capabilities: &corev1.Capabilities{
 			Drop: []corev1.Capability{
-				"ALL",
+				"MKNOD",
 			},
 		},
-		RunAsUser: &runAsUser,
+		RunAsUser:  &runAsUser,
+		RunAsGroup: &runAsGroup,
 		SeccompProfile: &corev1.SeccompProfile{
 			Type: corev1.SeccompProfileTypeRuntimeDefault,
 		},

pkg/glanceapi/cachejob.go

@@ -31,7 +31,7 @@ func ImageCacheJob(
 	instance *glancev1.GlanceAPI,
 	cronSpec glance.CronJobSpec,
 ) *batchv1.CronJob {
-	runAsUser := int64(0)
+	userID := glance.GlanceUID
 	var config0644AccessMode int32 = 0644
 
 	cronCommand := fmt.Sprintf(
@@ -100,6 +100,9 @@ func ImageCacheJob(
 					Completions: &completions,
 					Template: corev1.PodTemplateSpec{
 						Spec: corev1.PodSpec{
+							SecurityContext: &corev1.PodSecurityContext{
+								FSGroup: &userID,
+							},
 							Affinity: GetGlanceAPIPodAffinity(instance),
 							Containers: []corev1.Container{
 								{
@@ -108,11 +111,9 @@ func ImageCacheJob(
 									Command: []string{
 										"/bin/bash",
 									},
-									Args:         args,
-									VolumeMounts: cronJobVolumeMounts,
-									SecurityContext: &corev1.SecurityContext{
-										RunAsUser: &runAsUser,
-									},
+									Args:            args,
+									VolumeMounts:    cronJobVolumeMounts,
+									SecurityContext: glance.BaseSecurityContext(),
 								},
 							},
 							Volumes:            cronJobVolume,

pkg/glanceapi/statefulset.go

@@ -179,6 +179,9 @@ func StatefulSet(
 					Labels:      labels,
 				},
 				Spec: corev1.PodSpec{
+					SecurityContext: &corev1.PodSecurityContext{
+						FSGroup: &userID,
+					},
 					ServiceAccountName: instance.Spec.ServiceAccount,
 					// When using Cinder we run as privileged, but also some
 					// commands need to be run on the host using nsenter (eg: