mantle/platform: add BindMountHostRO Machine Option

docs/kola/external-tests.md

@@ -228,6 +228,7 @@ Here's an example `kola.json`:
     "additionalNics": 2,
     "appendKernelArgs": "enforcing=0"
     "appendFirstbootKernelArgs": "ip=bond0:dhcp bond=bond0:ens5,ens6:mode=active-backup,miimon=100"
+    "bindMountHostRO": ["/,/var/cosaroot"],
     "timeoutMin": 8,
     "exclusive": true,
     "conflicts": ["ext.config.some-test", "podman.some-other-test"],

mantle/cmd/kola/options.go

@@ -152,7 +152,7 @@ func init() {
 	bv(&kola.QEMUOptions.Disk512e, "qemu-512e", false, "Force 512e layout for main disk")
 	bv(&kola.QEMUOptions.Nvme, "qemu-nvme", false, "Use NVMe for main disk")
 	bv(&kola.QEMUOptions.Swtpm, "qemu-swtpm", true, "Create temporary software TPM")
-	ssv(&kola.QEMUOptions.BindRO, "qemu-bind-ro", nil, "Inject a host directory; this does not automatically mount in the guest")
+	ssv(&kola.QEMUOptions.BindRO, "qemu-bind-ro", nil, "Mount $hostpath,$guestpath readonly; for example --qemu-bind-ro=/path/on/host,/var/mnt/guest)")
 
 	sv(&kola.QEMUIsoOptions.IsoPath, "qemu-iso", "", "path to CoreOS ISO image")
 	bv(&kola.QEMUIsoOptions.AsDisk, "qemu-iso-as-disk", false, "attach ISO image as regular disk")

mantle/cmd/kola/qemuexec.go

@@ -125,14 +125,6 @@ func renderFragments(fragments []string, c *conf.Conf) error {
 	return nil
 }
 
-func parseBindOpt(s string) (string, string, error) {
-	parts := strings.SplitN(s, ",", 2)
-	if len(parts) == 1 {
-		return "", "", fmt.Errorf("malformed bind option, required: SRC,DEST")
-	}
-	return parts[0], parts[1], nil
-}
-
 // buildDiskFromOptions generates a disk image template using the process-global
 // defaults that were parsed from command line arguments.
 func buildDiskFromOptions() *platform.Disk {
@@ -304,7 +296,7 @@ func runQemuExec(cmd *cobra.Command, args []string) error {
 	}
 
 	for _, b := range bindro {
-		src, dest, err := parseBindOpt(b)
+		src, dest, err := platform.ParseBindOpt(b)
 		if err != nil {
 			return err
 		}
@@ -313,7 +305,7 @@ func runQemuExec(cmd *cobra.Command, args []string) error {
 		config.MountHost(dest, true)
 	}
 	for _, b := range bindrw {
-		src, dest, err := parseBindOpt(b)
+		src, dest, err := platform.ParseBindOpt(b)
 		if err != nil {
 			return err
 		}

mantle/kola/harness.go

@@ -23,6 +23,7 @@ import (
 	"math/rand"
 	"os"
 	"path/filepath"
+	"reflect"
 	"regexp"
 	"strconv"
 	"strings"
@@ -1015,6 +1016,7 @@ type externalTestMeta struct {
 	NoInstanceCreds           bool     `json:"noInstanceCreds"                     yaml:"noInstanceCreds"`
 	InstanceType              string   `json:"instanceType"                        yaml:"instanceType"`
 	Description               string   `json:"description"                         yaml:"description"`
+	BindMountHostRO           []string `json:"bindMountHostRO,omitempty"           yaml:"bindMountHostRO,omitempty"`
 }
 
 // metadataFromTestBinary extracts JSON-in-comment like:
@@ -1239,6 +1241,7 @@ ExecStart=%s
 		Tags:          []string{"external"},
 
 		MachineOptions: platform.MachineOptions{
+			BindMountHostRO:           targetMeta.BindMountHostRO,
 			AdditionalDisks:           targetMeta.AdditionalDisks,
 			PrimaryDisk:               targetMeta.PrimaryDisk,
 			MinMemory:                 targetMeta.MinMemory,
@@ -1622,8 +1625,8 @@ func makeNonExclusiveTest(bucket int, tests []*register.Test, flight platform.Fl
 		if test.HasFlag(register.AllowConfigWarnings) {
 			plog.Fatalf("Non-exclusive test %v cannot have AllowConfigWarnings flag", test.Name)
 		}
-		if test.MachineOptions.AppendKernelArgs != "" {
-			plog.Fatalf("Non-exclusive test %v cannot have AppendKernelArgs", test.Name)
+		if !reflect.DeepEqual(test.MachineOptions, platform.MachineOptions{}) {
+			plog.Fatalf("Non-exclusive test %v cannot have MachineOptions set", test.Name)
 		}
 		if !internetAccess && testRequiresInternet(test) {
 			tags = append(tags, NeedsInternetTag)

mantle/platform/machine/qemu/cluster.go

@@ -19,7 +19,6 @@ import (
 	"os"
 	"path/filepath"
 	"strconv"
-	"strings"
 	"sync/atomic"
 	"time"
 
@@ -86,6 +85,24 @@ func (qc *Cluster) NewMachineWithOptions(userdata *conf.UserData, options platfo
 		}
 	}
 
+	// If requested, bind mount Host (COSA) directories into the machine for use.
+	// These could either come in as MachineOptions OR via the flight options
+	// (CLI --qemu-bind-ro option).
+	//
+	// One example where this is useful is using the host environment (COSA)
+	// as a read-only rootfs for quickly starting a container. This use was originally
+	// pioneered in testiso in [1].
+	// [1] https://github.com/coreos/coreos-assembler/commit/8dbfe3ea8b8f571e732e8cc0ab307e983a0be1f3
+	for _, mountpair := range append(qc.flight.opts.BindRO, options.BindMountHostRO...) {
+		src, dest, err := platform.ParseBindOpt(mountpair)
+		if err != nil {
+			return nil, err
+		}
+		readonly := true
+		builder.MountHost(src, dest, readonly)
+		config.MountHost(dest, readonly)
+	}
+
 	builder.SetConfig(config)
 	defer builder.Close()
 	builder.UUID = qm.id
@@ -101,13 +118,6 @@ func (qc *Cluster) NewMachineWithOptions(userdata *conf.UserData, options platfo
 	builder.Hostname = fmt.Sprintf("qemu%d", qc.BaseCluster.AllocateMachineSerial())
 	builder.ConsoleFile = qm.consolePath
 
-	// This one doesn't support configuring the path because we can't
-	// reliably change the Ignition config here...
-	for _, path := range qc.flight.opts.BindRO {
-		destpathrel := strings.TrimLeft(path, "/")
-		builder.MountHost(path, "/kola/host/"+destpathrel, true)
-	}
-
 	if qc.flight.opts.Memory != "" {
 		memory, err := strconv.ParseInt(qc.flight.opts.Memory, 10, 32)
 		if err != nil {

mantle/platform/platform.go

@@ -176,6 +176,7 @@ type MachineOptions struct {
 	OverrideBackingFile       string
 	Nvme                      bool
 	Cex                       bool
+	BindMountHostRO           []string
 }
 
 // EnsureNoQEMUOnlyOptions returns an error if any QEMU-only options
@@ -221,6 +222,9 @@ func (m *MachineOptions) EnsureNoQEMUOnlyOptions(platformName string) error {
 	if m.Cex {
 		return fmt.Errorf("platform %s does not support Cex", platformName)
 	}
+	if len(m.BindMountHostRO) > 0 {
+		return fmt.Errorf("platform %s does not support bind mounting host paths", platformName)
+	}
 	return nil
 }
 

mantle/platform/qemu.go

@@ -149,6 +149,15 @@ func ParseDisk(spec string, allowNoSize bool) (*Disk, error) {
 	}, nil
 }
 
+// Parse the src/dest for BindRO and BindRW options
+func ParseBindOpt(spec string) (string, string, error) {
+	parts := strings.SplitN(spec, ",", 2)
+	if len(parts) == 1 {
+		return "", "", fmt.Errorf("malformed bind option, required: SRC,DEST")
+	}
+	return parts[0], parts[1], nil
+}
+
 // bootIso is an internal struct used by AddIso() and setupIso()
 type bootIso struct {
 	path      string

src/deps.txt

@@ -117,3 +117,7 @@ vim-enhanced
 
 # For reading build-args.conf (environment file)
 python3-dotenv
+
+# For testing numad
+# https://github.com/coreos/fedora-coreos-config/pull/4051
+stress-ng