[tmpnet] Bootstrap subnets with a single node

Speed up subnet creation for a network of multiple nodes by:

 - starting a single node with sybil protection disabled
 - creating subnets and chains
 - restarting the node with sybil protection enabled
 - starting the remaining nodes

.github/workflows/ci.yml

@@ -82,7 +82,7 @@ jobs:
           FILTER_BY_OWNER: avalanchego-e2e
       - name: Run e2e tests
         shell: bash
-        run: E2E_SERIAL=1 ./scripts/tests.e2e.sh
+        run: E2E_SERIAL=1 ./scripts/tests.e2e.sh --delay-network-shutdown
         env:
           GH_REPO: ${{ github.repository }}
           GH_WORKFLOW: ${{ github.workflow }}
@@ -132,7 +132,7 @@ jobs:
           GH_JOB_ID: ${{ github.job }}
       - name: Run e2e tests with existing network
         shell: bash
-        run: E2E_SERIAL=1 ./scripts/tests.e2e.existing.sh
+        run: E2E_SERIAL=1 ./scripts/tests.e2e.existing.sh --delay-network-shutdown
         env:
           GH_REPO: ${{ github.repository }}
           GH_WORKFLOW: ${{ github.workflow }}

scripts/tests.e2e.existing.sh

@@ -6,6 +6,7 @@ set -euo pipefail
 
 # e.g.,
 # ./scripts/build.sh
+# ./scripts/tests.e2e.sh --ginkgo.label-filter=x                        # All arguments are supplied to ginkgo
 # AVALANCHEGO_PATH=./build/avalanchego ./scripts/tests.e2e.existing.sh  # Customization of avalanchego path
 if ! [[ "$0" =~ scripts/tests.e2e.existing.sh ]]; then
   echo "must be run from repository root"
@@ -27,7 +28,7 @@ trap cleanup EXIT
 
 print_separator
 echo "starting initial test run that should create the reusable network"
-./scripts/tests.e2e.sh --reuse-network --ginkgo.focus-file=xsvm.go
+./scripts/tests.e2e.sh --reuse-network --ginkgo.focus-file=xsvm.go "${@}"
 
 print_separator
 echo "determining the network path of the reusable network created by the first test run"
@@ -36,7 +37,7 @@ INITIAL_NETWORK_DIR="$(realpath "${SYMLINK_PATH}")"
 
 print_separator
 echo "starting second test run that should reuse the network created by the first run"
-./scripts/tests.e2e.sh --reuse-network --ginkgo.focus-file=xsvm.go
+./scripts/tests.e2e.sh --reuse-network --ginkgo.focus-file=xsvm.go "${@}"
 
 SUBSEQUENT_NETWORK_DIR="$(realpath "${SYMLINK_PATH}")"
 echo "checking that the symlink path remains the same, indicating that the network was reused"

tests/fixture/e2e/flags.go

@@ -17,6 +17,7 @@ type FlagVars struct {
 	pluginDir            string
 	networkDir           string
 	reuseNetwork         bool
+	delayNetworkShutdown bool
 	networkShutdownDelay time.Duration
 	stopNetwork          bool
 	nodeCount            int
@@ -45,7 +46,11 @@ func (v *FlagVars) ReuseNetwork() bool {
 }
 
 func (v *FlagVars) NetworkShutdownDelay() time.Duration {
-	return v.networkShutdownDelay
+	if v.delayNetworkShutdown {
+		// Only return a non-zero value if the delay is enabled
+		return v.networkShutdownDelay
+	}
+	return 0
 }
 
 func (v *FlagVars) StopNetwork() bool {
@@ -82,11 +87,17 @@ func RegisterFlags() *FlagVars {
 		false,
 		"[optional] reuse an existing network. If an existing network is not already running, create a new one and leave it running for subsequent usage.",
 	)
+	flag.BoolVar(
+		&vars.delayNetworkShutdown,
+		"delay-network-shutdown",
+		false,
+		"[optional] whether to delay network shutdown to allow a final metrics scrape. The duration is set with --network-shutdown-delay.",
+	)
 	flag.DurationVar(
 		&vars.networkShutdownDelay,
 		"network-shutdown-delay",
 		12*time.Second, // Make sure this value takes into account the scrape_interval defined in scripts/run_prometheus.sh
-		"[optional] the duration to wait before shutting down the test network at the end of the test run. A value greater than the scrape interval is suggested. 0 avoids waiting for shutdown.",
+		"[optional] the duration to wait before shutting down the test network at the end of the test run. A value greater than the scrape interval is suggested.",
 	)
 	flag.BoolVar(
 		&vars.stopNetwork,

tests/fixture/e2e/helpers.go

@@ -226,7 +226,7 @@ func StartNetwork(
 	require := require.New(ginkgo.GinkgoT())
 
 	require.NoError(
-		tmpnet.StartNewNetwork(
+		tmpnet.BootstrapNewNetwork(
 			DefaultContext(),
 			ginkgo.GinkgoWriter,
 			network,

tests/fixture/tmpnet/README.md

@@ -103,7 +103,7 @@ network := &tmpnet.Network{                   // Configure non-default values fo
     },
 }
 
-_ := tmpnet.StartNewNetwork(              // Start the network
+_ := tmpnet.BootstrapNewNetwork(          // Bootstrap the network
     ctx,                                  // Context used to limit duration of waiting for network health
     ginkgo.GinkgoWriter,                  // Writer to report progress of initialization
     network,

tests/fixture/tmpnet/cmd/main.go

@@ -74,7 +74,7 @@ func main() {
 
 			ctx, cancel := context.WithTimeout(context.Background(), networkStartTimeout)
 			defer cancel()
-			err := tmpnet.StartNewNetwork(
+			err := tmpnet.BootstrapNewNetwork(
 				ctx,
 				os.Stdout,
 				network,

tests/fixture/tmpnet/network.go

@@ -119,7 +119,7 @@ func toCanonicalDir(dir string) (string, error) {
 	return filepath.EvalSymlinks(absDir)
 }
 
-func StartNewNetwork(
+func BootstrapNewNetwork(
 	ctx context.Context,
 	w io.Writer,
 	network *Network,
@@ -136,10 +136,7 @@ func StartNewNetwork(
 	if err := network.Create(rootNetworkDir); err != nil {
 		return err
 	}
-	if err := network.Start(ctx, w); err != nil {
-		return err
-	}
-	return network.CreateSubnets(ctx, w)
+	return network.Bootstrap(ctx, w)
 }
 
 // Stops the nodes of the network configured in the provided directory.
@@ -317,26 +314,33 @@ func (n *Network) Create(rootDir string) error {
 	return n.Write()
 }
 
-// Starts all nodes in the network
-func (n *Network) Start(ctx context.Context, w io.Writer) error {
-	if _, err := fmt.Fprintf(w, "Starting network %s (UUID: %s)\n", n.Dir, n.UUID); err != nil {
-		return err
+// Starts the specified nodes
+func (n *Network) Start(ctx context.Context, w io.Writer, nodesToStart ...*Node) error {
+	nodesToWaitFor := nodesToStart
+	if len(nodesToStart) < len(n.Nodes) && nodesToStart[0] != n.Nodes[0] {
+		// Wait for all nodes to ensure health is logged for the bootstrap node
+		nodesToWaitFor = n.Nodes
+	} else {
+		// Simplify output by only logging network start for the first node or when all nodes are starting at once
+		if _, err := fmt.Fprintf(w, "Starting network %s (UUID: %s)\n", n.Dir, n.UUID); err != nil {
+			return err
+		}
 	}
 
 	// Record the time before nodes are started to ensure visibility of subsequently collected metrics via the emitted link
 	startTime := time.Now()
 
 	// Configure the networking for each node and start
-	for _, node := range n.Nodes {
+	for _, node := range nodesToStart {
 		if err := n.StartNode(ctx, w, node); err != nil {
 			return err
 		}
 	}
 
-	if _, err := fmt.Fprint(w, "Waiting for all nodes to report healthy...\n\n"); err != nil {
+	if _, err := fmt.Fprint(w, "Waiting for nodes to report healthy...\n\n"); err != nil {
 		return err
 	}
-	if err := n.WaitForHealthy(ctx, w); err != nil {
+	if err := n.WaitForHealthy(ctx, w, nodesToWaitFor); err != nil {
 		return err
 	}
 	if _, err := fmt.Fprintf(w, "\nStarted network %s (UUID: %s)\n", n.Dir, n.UUID); err != nil {
@@ -350,6 +354,48 @@ func (n *Network) Start(ctx context.Context, w io.Writer) error {
 	return nil
 }
 
+// Start the network for the first time
+func (n *Network) Bootstrap(ctx context.Context, w io.Writer) error {
+	if len(n.Subnets) == 0 || len(n.Nodes) == 1 {
+		// Start all nodes at once if a staged start is not worth it
+		return n.Start(ctx, w, n.Nodes...)
+	}
+
+	// Reduce the cost of subnet creation for a network of multiple nodes by
+	// creating subnets with a single node with sybil protection
+	// disabled. This allows the creation of initial subnet state without
+	// requiring coordination between multiple nodes.
+
+	bootstrapNode := n.Nodes[0]
+	if _, err := fmt.Fprintf(w, "Starting a single-node network with %s for quicker subnet creation\n", bootstrapNode.NodeID); err != nil {
+		return err
+	}
+	bootstrapNode.Flags[config.SybilProtectionEnabledKey] = false
+	if err := n.Start(ctx, w, bootstrapNode); err != nil {
+		return err
+	}
+	if err := n.CreateSubnets(ctx, w); err != nil {
+		return err
+	}
+
+	if _, err := fmt.Fprintf(w, "Restarting %s with sybil protection enabled to serve as bootstrap node\n", bootstrapNode.NodeID); err != nil {
+		return err
+	}
+	delete(bootstrapNode.Flags, config.SybilProtectionEnabledKey)
+	// Avoid using RestartNode since the node won't be able to report healthy until other nodes are started.
+	if err := bootstrapNode.Stop(ctx); err != nil {
+		return fmt.Errorf("failed to stop node %s: %w", bootstrapNode.NodeID, err)
+	}
+	if err := n.StartNode(ctx, w, bootstrapNode); err != nil {
+		return fmt.Errorf("failed to start node %s: %w", bootstrapNode.NodeID, err)
+	}
+
+	if _, err := fmt.Fprint(w, "Starting remaining nodes...\n"); err != nil {
+		return err
+	}
+	return n.Start(ctx, w, n.Nodes[1:]...)
+}
+
 // Starts the provided node after configuring it for the network.
 func (n *Network) StartNode(ctx context.Context, w io.Writer, node *Node) error {
 	if err := n.EnsureNodeConfig(node); err != nil {
@@ -408,13 +454,13 @@ func (n *Network) RestartNode(ctx context.Context, w io.Writer, node *Node) erro
 }
 
 // Waits until all nodes in the network are healthy.
-func (n *Network) WaitForHealthy(ctx context.Context, w io.Writer) error {
+func (n *Network) WaitForHealthy(ctx context.Context, w io.Writer, nodes []*Node) error {
 	ticker := time.NewTicker(networkHealthCheckInterval)
 	defer ticker.Stop()
 
-	healthyNodes := set.NewSet[ids.NodeID](len(n.Nodes))
-	for healthyNodes.Len() < len(n.Nodes) {
-		for _, node := range n.Nodes {
+	healthyNodes := set.NewSet[ids.NodeID](len(nodes))
+	for healthyNodes.Len() < len(nodes) {
+		for _, node := range nodes {
 			if healthyNodes.Contains(node.NodeID) {
 				continue
 			}
@@ -650,6 +696,10 @@ func (n *Network) CreateSubnets(ctx context.Context, w io.Writer) error {
 		reconfiguredNodes = append(reconfiguredNodes, node)
 	}
 	for _, node := range reconfiguredNodes {
+		if len(node.URI) == 0 {
+			// Only running nodes should be restarted
+			continue
+		}
 		if err := n.RestartNode(ctx, w, node); err != nil {
 			return err
 		}

tests/fixture/tmpnet/node.go

@@ -369,6 +369,10 @@ func (n *Node) EnsureNodeID() error {
 // labeling of metrics.
 func (n *Node) SaveAPIPort() error {
 	hostPort := strings.TrimPrefix(n.URI, "http://")
+	if len(hostPort) == 0 {
+		// Without a staking address there is nothing to save
+		return nil
+	}
 	_, port, err := net.SplitHostPort(hostPort)
 	if err != nil {
 		return err

tests/fixture/tmpnet/node_process.go

@@ -139,6 +139,10 @@ func (p *NodeProcess) Start(w io.Writer) error {
 	// A node writes a process context file on start. If the file is not
 	// found in a reasonable amount of time, the node is unlikely to have
 	// started successfully.
+	//
+	// TODO(marun) Consider waiting for the process context only for a
+	// bootstrap node (i.e. len(bootstrapIDs) == 0) to minimize
+	// startup time for larger numbers of nodes.
 	if err := p.waitForProcessContext(context.Background()); err != nil {
 		return fmt.Errorf("failed to start local node: %w", err)
 	}