fix(gre-mesh): ensure bridge exists before creating GRE tunnels

src/go/api/experiment/experiment.go

@@ -552,6 +552,26 @@ func Start(ctx context.Context, opts ...StartOption) error {
  }
  }
 
+ // Creating experiment bridge after launching VMs to ensure the bridge
+ // already exists in minimega (and OVS) before creating GRE tunnels between
+ // them. This cannot be done as part of the minimega script template since
+ // the VM taps (and thus bridges) do not get created until the overall
+ // minimega namespace is launched.
+ if exp.Spec.UseGREMesh() || exp.Spec.DefaultBridge() != "phenix" {
+ if err := mm.CreateBridge(mm.NS(exp.Metadata.Name), mm.Bridge(exp.Spec.DefaultBridge())); err != nil {
+ if !o.mmErrAsWarn {
+ mm.ClearNamespace(exp.Spec.ExperimentName())
+ return fmt.Errorf("creating experiment bridge: %w", err)
+ }
+
+ if merr, ok := err.(*multierror.Error); ok {
+ notes.AddWarnings(ctx, false, merr.Errors...)
+ } else {
+ notes.AddWarnings(ctx, false, err)
+ }
+ }
+ }
+
  schedule := make(map[string]string)
 
  for _, vm := range mm.GetVMInfo(mm.NS(exp.Spec.ExperimentName())) {

src/go/tmpl/templates/minimega_script.tmpl

@@ -18,10 +18,6 @@ ns del-host all
 ns add-host localhost
 {{- end }}
 
-{{- if or (ne .DefaultBridge "phenix") .UseGREMesh }}
-ns bridge {{ .DefaultBridge }} gre
-{{- end }}
-
 {{- $basedir := .BaseDir }}
 
 {{- range .Topology.Nodes }}

src/go/util/mm/minimega.go

@@ -507,6 +507,19 @@ func (Minimega) DisconnectVMInterface(opts ...Option) error {
  return nil
 }
 
+func (Minimega) CreateBridge(opts ...Option) error {
+ o := NewOptions(opts...)
+
+ cmd := mmcli.NewNamespacedCommand(o.ns)
+ cmd.Command = fmt.Sprintf("ns bridge %s gre", o.bridge)
+
+ if err := mmcli.ErrorResponse(mmcli.Run(cmd)); err != nil {
+ return fmt.Errorf("creating bridge %s with GRE mesh between namespace hosts: %w", o.bridge, err)
+ }
+
+ return nil
+}
+
 func (Minimega) CreateTunnel(opts ...Option) error {
  host, err := GetVMHost(opts...)
  if err != nil {

src/go/util/mm/mm.go

@@ -22,6 +22,8 @@ type MM interface {
  ConnectVMInterface(...Option) error
  DisconnectVMInterface(...Option) error
 
+ CreateBridge(...Option) error
+
  CreateTunnel(...Option) error
  GetTunnels(...Option) []map[string]string
  CloseTunnel(...Option) error

src/go/util/mm/option.go

@@ -10,11 +10,12 @@ import (
 type Option func(*options)
 
 type options struct {
- ns string
- vm string
- cpu int
- mem int
- disk string
+ ns string
+ vm string
+ cpu int
+ mem int
+ disk string
+ bridge string
 
  injectPart int
  injects []string
@@ -73,6 +74,12 @@ func Disk(d string) Option {
  }
 }
 
+func Bridge(b string) Option {
+ return func(o *options) {
+ o.bridge = b
+ }
+}
+
 func InjectPartition(p int) Option {
  return func(o *options) {
  o.injectPart = p

src/go/util/mm/package.go

@@ -60,6 +60,10 @@ func DisconnectVMInterface(opts ...Option) error {
  return DefaultMM.DisconnectVMInterface(opts...)
 }
 
+func CreateBridge(opts ...Option) error {
+ return DefaultMM.CreateBridge(opts...)
+}
+
 func CreateTunnel(opts ...Option) error {
  return DefaultMM.CreateTunnel(opts...)
 }