Add downwardMetrics volume to KubeVirt to allow exposing host metrics to guests

WORKSPACE

@@ -448,9 +448,9 @@ container_pull(
 # TODO build fedora_with_test_tooling for multi-arch
 container_pull(
     name = "fedora_with_test_tooling",
-    digest = "sha256:9ec3e137bff093597d192f5a4e346f25b614c3a94216b857de0e3d75b68bfb17",
+    digest = "sha256:24bac3f1653ef0bc918c8aa5ee1043ad01ac2b7bee75137194fd0c8db06b73c6",
     registry = "quay.io",
-    repository = "kubevirt/fedora-with-test-tooling",
+    repository = "kubevirtci/fedora-with-test-tooling",
 )
 
 container_pull(

api/openapi-spec/swagger.json

@@ -9640,6 +9640,10 @@
      }
     }
    },
+   "v1.DownwardMetricsVolumeSource": {
+    "description": "DownwardMetricsVolumeSource adds a very small disk to VMIs which contains a limited view of host and guest metrics. The disk content is compatible with vhostmd (https://github.com/vhostmd/vhostmd) and vm-dump-metrics.",
+    "type": "object"
+   },
    "v1.EFI": {
     "description": "If set, EFI will be used instead of BIOS.",
     "type": "object",
@@ -12206,6 +12210,10 @@
       "description": "DownwardAPI represents downward API about the pod that should populate this volume",
       "$ref": "#/definitions/v1.DownwardAPIVolumeSource"
      },
+     "downwardMetrics": {
+      "description": "DownwardMetrics adds a very small disk to VMIs which contains a limited view of host and guest metrics. The disk content is compatible with vhostmd (https://github.com/vhostmd/vhostmd) and vm-dump-metrics.",
+      "$ref": "#/definitions/v1.DownwardMetricsVolumeSource"
+     },
      "emptyDisk": {
       "description": "EmptyDisk represents a temporary disk which shares the vmis lifecycle. More info: https://kubevirt.gitbooks.io/user-guide/disks-and-volumes.html",
       "$ref": "#/definitions/v1.EmptyDiskSource"

cmd/virt-handler/BUILD.bazel

@@ -13,6 +13,7 @@ go_library(
         "//pkg/inotify-informer:go_default_library",
         "//pkg/monitoring/client/prometheus:go_default_library",
         "//pkg/monitoring/reflector/prometheus:go_default_library",
+        "//pkg/monitoring/vms/downwardmetrics:go_default_library",
         "//pkg/monitoring/vms/prometheus:go_default_library",
         "//pkg/monitoring/workqueue/prometheus:go_default_library",
         "//pkg/service:go_default_library",

cmd/virt-handler/virt-handler.go

@@ -45,6 +45,8 @@ import (
 	"k8s.io/client-go/tools/record"
 	"k8s.io/client-go/util/certificate"
 
+	"kubevirt.io/kubevirt/pkg/monitoring/vms/downwardmetrics"
+
 	"kubevirt.io/kubevirt/pkg/healthz"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -321,6 +323,9 @@ func (app *virtHandlerApp) Run() {
 	)
 
 	promvm.SetupCollector(app.virtCli, app.VirtShareDir, app.HostOverride, app.MaxRequestsInFlight, vmiSourceInformer)
+	if err := downwardmetrics.RunDownwardMetricsCollector(context.Background(), app.HostOverride, vmiSourceInformer, podIsolationDetector); err != nil {
+		panic(fmt.Errorf("failed to set up the downwardMetrics collector: %v", err))
+	}
 
 	go app.clientcertmanager.Start()
 	go app.servercertmanager.Start()

go.mod

@@ -3,6 +3,7 @@ module kubevirt.io/kubevirt
 require (
 	github.com/Masterminds/semver v1.5.0
 	github.com/blang/semver v3.5.1+incompatible
+	github.com/c9s/goprocinfo v0.0.0-20210130143923-c95fcf8c64a8
 	github.com/containernetworking/plugins v0.8.2
 	github.com/coreos/go-iptables v0.4.3
 	github.com/coreos/go-semver v0.3.0

go.sum

@@ -83,6 +83,8 @@ github.com/blang/semver v3.5.1+incompatible h1:cQNTCjp13qL8KC3Nbxr/y2Bqb63oX6wdn
 github.com/blang/semver v3.5.1+incompatible/go.mod h1:kRBLl5iJ+tD4TcOOxsy/0fnwebNt5EWlYSAyrTnjyyk=
 github.com/brancz/gojsontoyaml v0.0.0-20190425155809-e8bd32d46b3d/go.mod h1:IyUJYN1gvWjtLF5ZuygmxbnsAyP3aJS6cHzIuZY50B0=
 github.com/buger/jsonparser v0.0.0-20180808090653-f4dd9f5a6b44/go.mod h1:bbYlZJ7hK1yFx9hf58LP0zeX7UjIGs20ufpu3evjr+s=
+github.com/c9s/goprocinfo v0.0.0-20210130143923-c95fcf8c64a8 h1:SjZ2GvvOononHOpK84APFuMvxqsk3tEIaKH/z4Rpu3g=
+github.com/c9s/goprocinfo v0.0.0-20210130143923-c95fcf8c64a8/go.mod h1:uEyr4WpAH4hio6LFriaPkL938XnrvLpNPmQHBdrmbIE=
 github.com/campoy/embedmd v1.0.0/go.mod h1:oxyr9RCiSXg0M3VJ3ks0UGfp98BpSSGr0kpiX3MzVl8=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/certifi/gocertifi v0.0.0-20180905225744-ee1a9a0726d2/go.mod h1:GJKEexRPVJrBSOjoqN5VNOIKJ5Q3RViH6eu3puDRwx4=

hack/check-for-binaries.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 
 if diff <(git grep -c '') <(git grep -cI '') |
-    grep -E -v -e 'docs/.*\.png|swagger-ui' -e 'vendor/*' -e 'assets/*' |
+    grep -E -v -e 'docs/.*\.png|swagger-ui' -e 'vendor/*' -e 'assets/*' -e 'pkg/downwardmetrics/vhostmd/testdata/vhostmd0' |
     grep '^<'; then
     echo "Binary files are present in git repostory."
     exit 1

pkg/config/config.go

@@ -69,6 +69,10 @@ var (
 	SysprepDisksDir = mountBaseDir + "/sysprep-disks"
 	// DownwardAPIDisksDir represents a path to DownwardAPI iso images
 	DownwardAPIDisksDir = mountBaseDir + "/downwardapi-disks"
+	// DownwardMetricDisksDir represents a path to DownwardMetric block disk
+	DownwardMetricDisksDir = mountBaseDir + "/downwardmetric-disk"
+	// DownwardMetricDisks represents the disk location for the DownwardMetric disk
+	DownwardMetricDisk = filepath.Join(DownwardAPIDisksDir, "vhostmd0")
 	// ServiceAccountDiskDir represents a path to the ServiceAccount iso image
 	ServiceAccountDiskDir = mountBaseDir + "/service-account-disk"
 	// ServiceAccountDiskName represents the name of the ServiceAccount iso image

pkg/downwardmetrics/BUILD.bazel

@@ -0,0 +1,13 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["downwardmetrics.go"],
+    importpath = "kubevirt.io/kubevirt/pkg/downwardmetrics",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//pkg/config:go_default_library",
+        "//pkg/downwardmetrics/vhostmd:go_default_library",
+        "//staging/src/kubevirt.io/client-go/api/v1:go_default_library",
+    ],
+)

pkg/downwardmetrics/downwardmetrics.go

@@ -0,0 +1,32 @@
+package downwardmetrics
+
+import (
+	"path/filepath"
+	"strconv"
+
+	v1 "kubevirt.io/client-go/api/v1"
+	"kubevirt.io/kubevirt/pkg/config"
+	"kubevirt.io/kubevirt/pkg/downwardmetrics/vhostmd"
+)
+
+func CreateDownwardMetricDisk(vmi *v1.VirtualMachineInstance) error {
+	for _, volume := range vmi.Spec.Volumes {
+		if volume.DownwardMetrics != nil {
+			return vhostmd.NewMetricsIODisk(config.DownwardMetricDisk).Create()
+		}
+	}
+	return nil
+}
+
+func FormatDownwardMetricPath(pid int) string {
+	return filepath.Join("/proc", strconv.Itoa(pid), "/root", config.DownwardMetricDisk)
+}
+
+func HasDownwardMetricDisk(vmi *v1.VirtualMachineInstance) bool {
+	for _, volume := range vmi.Spec.Volumes {
+		if volume.DownwardMetrics != nil {
+			return true
+		}
+	}
+	return false
+}

pkg/downwardmetrics/vhostmd/BUILD.bazel

@@ -0,0 +1,29 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "disk.go",
+        "vhostmd.go",
+    ],
+    importpath = "kubevirt.io/kubevirt/pkg/downwardmetrics/vhostmd",
+    visibility = ["//visibility:public"],
+    deps = ["//pkg/downwardmetrics/vhostmd/api:go_default_library"],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = [
+        "disk_test.go",
+        "vhostmd_suite_test.go",
+    ],
+    data = glob(["testdata/**"]),
+    embed = [":go_default_library"],
+    deps = [
+        "//pkg/downwardmetrics/vhostmd/api:go_default_library",
+        "//pkg/downwardmetrics/vhostmd/metrics:go_default_library",
+        "//staging/src/kubevirt.io/client-go/testutils:go_default_library",
+        "//vendor/github.com/onsi/ginkgo:go_default_library",
+        "//vendor/github.com/onsi/gomega:go_default_library",
+    ],
+)

pkg/downwardmetrics/vhostmd/api/BUILD.bazel

@@ -0,0 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["api.go"],
+    importpath = "kubevirt.io/kubevirt/pkg/downwardmetrics/vhostmd/api",
+    visibility = ["//visibility:public"],
+)

pkg/downwardmetrics/vhostmd/api/api.go

@@ -0,0 +1,36 @@
+package api
+
+import "encoding/xml"
+
+type MetricContext string
+type MetricType string
+
+const (
+	MetricContextHost MetricContext = "host"
+	MetricContextVM   MetricContext = "vm"
+)
+
+const (
+	MetricTypeReal64 MetricType = "real64"
+	MetricTypeReal32 MetricType = "real32"
+	MetricTypeInt64  MetricType = "int64"
+	MetricTypeInt32  MetricType = "int32"
+	MetricTypeUInt64 MetricType = "uint64"
+	MetricTypeUInt32 MetricType = "uint32"
+	MetricTypeString MetricType = "string"
+)
+
+type Metrics struct {
+	XMLName xml.Name `xml:"metrics"`
+	Text    string   `xml:",chardata"`
+	Metrics []Metric `xml:"metric"`
+}
+
+type Metric struct {
+	Text    string        `xml:",chardata"`
+	Type    MetricType    `xml:"type,attr"`
+	Context MetricContext `xml:"context,attr"`
+	Name    string        `xml:"name"`
+	Value   string        `xml:"value"`
+	Unit    string        `xml:"unit,attr,omitempty"`
+}