fix: teardown removes the lease file the daemon writes

cmd/adopt.go

@@ -84,6 +84,7 @@ func runAdopt(cmd *cobra.Command, _ []string) error {
 		fmt.Printf("  gateway:         %s\n", gateway)
 		fmt.Printf("  primary-nic:     %s\n", primaryNIC)
 		fmt.Printf("  secondary-nics:  %s\n", strings.Join(secondaryNICs, ","))
+		fmt.Printf("  enis:            %s\n", cmp.Or(strings.Join(eniIDs, ","), "none"))
 		if len(ips) > 0 {
 			fmt.Printf("  pool-size:       %d (first=%s, last=%s)\n", len(ips), ips[0], ips[len(ips)-1])
 		} else {

cmd/daemon.go

@@ -9,6 +9,7 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"path/filepath"
 	"time"
 
 	"github.com/projecteru2/core/log"
@@ -24,7 +25,6 @@ import (
 )
 
 const (
-	defaultLeaseFile     = "/var/lib/cocoon/net/leases.json"
 	defaultControlSocket = "/run/cocoon-net/control.sock"
 	defaultMetricsAddr   = ":9092"
 
@@ -52,7 +52,7 @@ they expire.`,
 		RunE: runDaemon,
 	}
 	cmd.Flags().StringVar(&flagStateDir, "state-dir", defaultStateDir, "directory containing pool.json")
-	cmd.Flags().StringVar(&flagLeaseFile, "lease-file", defaultLeaseFile, "path to lease persistence file")
+	cmd.Flags().StringVar(&flagLeaseFile, "lease-file", defaultLeaseFile, "lease persistence file")
 	cmd.Flags().StringVar(&flagControlSocket, "control-socket", cmp.Or(os.Getenv("COCOON_NET_CONTROL_SOCKET"), defaultControlSocket), "root-only Unix socket for local lease lifecycle operations (empty to disable)")
 	cmd.Flags().BoolVar(&flagSkipIPTables, "skip-iptables", false, "skip iptables setup (for pre-configured nodes)")
 	cmd.Flags().StringVar(&flagMetricsAddr, "metrics-addr", cmp.Or(os.Getenv("COCOON_NET_METRICS_ADDR"), defaultMetricsAddr), "prometheus metrics listen address (empty to disable)")
@@ -104,6 +104,9 @@ func runDaemon(cmd *cobra.Command, _ []string) error {
 	}
 	dnsIPs := parseIPs(dnsList)
 
+	if err := os.MkdirAll(filepath.Dir(flagLeaseFile), 0o750); err != nil {
+		return fmt.Errorf("create lease dir: %w", err)
+	}
 	srv := dhcp.New(dhcp.Config{
 		Interface:     node.BridgeName,
 		Gateway:       gateway,

cmd/teardown.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"io/fs"
 	"os"
-	"path/filepath"
 
 	"github.com/projecteru2/core/log"
 	"github.com/spf13/cobra"
@@ -14,8 +13,6 @@ import (
 	"github.com/cocoonstack/cocoon-net/platform"
 )
 
-const leaseFileName = "leases.json"
-
 func newTeardownCmd() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "teardown",
@@ -67,7 +64,7 @@ func runTeardown(cmd *cobra.Command, _ []string) error {
 		logger.Warnf(ctx, "delete pool state: %v", err)
 	}
 
-	leasePath := filepath.Join(flagStateDir, leaseFileName)
+	leasePath := defaultLeaseFile
 	if err := os.Remove(leasePath); err != nil && !errors.Is(err, fs.ErrNotExist) {
 		logger.Warnf(ctx, "delete lease file %s: %v", leasePath, err)
 	}

cmd/utils.go

@@ -13,7 +13,11 @@ import (
 	"github.com/cocoonstack/cocoon-net/pool"
 )
 
-const defaultStateDir = "/var/lib/cocoon/net"
+const (
+	defaultStateDir  = "/var/lib/cocoon/net"
+	leaseFileName    = "leases.json"
+	defaultLeaseFile = defaultStateDir + "/" + leaseFileName
+)
 
 var (
 	flagPlatform     string
@@ -38,7 +42,7 @@ func registerCommonFlags(cmd *cobra.Command, defaultPoolSize int) {
 	cmd.Flags().StringVar(&flagSubnet, "subnet", "", "VM subnet CIDR, e.g. 172.20.100.0/24 (required)")
 	cmd.Flags().IntVar(&flagPoolSize, "pool-size", defaultPoolSize, "number of IPs in the pool")
 	cmd.Flags().StringVar(&flagGateway, "gateway", "", "gateway IP on cni0 (default: first IP in subnet)")
-	cmd.Flags().StringVar(&flagPrimaryNIC, "primary-nic", "", "host primary NIC (auto-detect if empty)")
+	cmd.Flags().StringVar(&flagPrimaryNIC, "primary-nic", "", "host primary NIC (default: eth0 on volcengine, ens4 otherwise)")
 	cmd.Flags().StringVar(&flagDNS, "dns", "8.8.8.8,1.1.1.1", "comma-separated DNS servers for DHCP clients")
 	cmd.Flags().StringVar(&flagStateDir, "state-dir", defaultStateDir, "state directory")
 	cmd.Flags().BoolVar(&flagDryRun, "dry-run", false, "show what would be done without making changes")

docs/dhcp.md

@@ -25,7 +25,8 @@ VPC-routable IP directly from this server.
   `204` after a successful or already-completed release, `400` for an invalid
   MAC, and `500` when persistence fails; callers may safely retry a `500`.
 - Leases are persisted to the `--lease-file` (default
-  `/var/lib/cocoon/net/leases.json`) on every allocation/release, and
+  `/var/lib/cocoon/net/leases.json`, independent of `--state-dir` so
+  vk-cocoon's default reader path matches) on every allocation/release, and
   reloaded at daemon startup so a restart doesn't strand or double-assign
   leases.
 
@@ -125,8 +126,8 @@ The DHCP server binds UDP port 67 on all addresses, not just `cni0`; a host
 `dnsmasq` or `dhcpd` already holding that port makes the daemon fail to start.
 
 On `cocoon-net teardown`, the cloud resources (ENIs on Volcengine, the alias
-range on GKE), the tagged `cocoon-net-drop` iptables rules, `pool.json`, and
-`<state-dir>/leases.json` are all removed (on GKE the boot cron job that
+range on GKE), the tagged `cocoon-net-drop` iptables rules, `pool.json`, and the
+default lease file `/var/lib/cocoon/net/leases.json` are all removed (on GKE the boot cron job that
 reapplies the guest-agent route fix is removed too); a daemon started with a
 custom `--lease-file` keeps that file. The `cni0` bridge, the FORWARD ACCEPT /
 NAT MASQUERADE rules, and the CNI conflist are left in place.

platform/ip_test.go

@@ -45,7 +45,6 @@ func TestSubnetIPs_Slash24SkipsBroadcast(t *testing.T) {
 func TestSubnetIPs_Slash28(t *testing.T) {
 	t.Parallel()
 
-	// /28 has 16 addresses, 14 hosts, minus gateway = 13.
 	got, err := SubnetIPs("192.168.10.0/28", "192.168.10.1", 32)
 	if err != nil {
 		t.Fatalf("SubnetIPs: %v", err)

platform/volcengine/adopt.go

@@ -6,4 +6,5 @@ import (
 	"github.com/cocoonstack/cocoon-net/platform"
 )
 
+// Adopt is a no-op: the VPC routes the VM subnet to the secondary ENIs, so no host route hijacks it.
 func (v *Volcengine) Adopt(context.Context, *platform.Config) error { return nil }