feat: add GitHub Actions release workflow and improve docs

- Add GitHub Actions workflow for multi-platform releases - Build for linux/darwin on amd64/arm64 - Auto-create GitHub Release with checksums - Version injection via ldflags - Add init.d script support for install command - Rewrite README with clearer documentation - Quick start guide - Two-node HA setup example - Health check configuration - Troubleshooting section - Bump version to 1.2.1 🤖 Generated with [Qoder][https://qoder.com]
feat: add install command for easy deployment
2026-03-04 23:36:09 -08:00 · 2026-03-04 00:54:08 -08:00 · 2026-03-04 00:14:47 -08:00
16 changed files with 1189 additions and 452 deletions
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -0,0 +1,95 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    name: Build ${{ matrix.os }}-${{ matrix.arch }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        include:
+          - os: linux
+            arch: amd64
+          - os: linux
+            arch: arm64
+          - os: darwin
+            arch: amd64
+          - os: darwin
+            arch: arm64
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.21'
+
+      - name: Get version
+        id: version
+        run: echo "VERSION=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
+
+      - name: Build binary
+        env:
+          GOOS: ${{ matrix.os }}
+          GOARCH: ${{ matrix.arch }}
+          CGO_ENABLED: 0
+        run: |
+          mkdir -p dist
+          BINARY_NAME=go-alived-${{ matrix.os }}-${{ matrix.arch }}
+          if [ "${{ matrix.os }}" = "windows" ]; then
+            BINARY_NAME="${BINARY_NAME}.exe"
+          fi
+          go build -ldflags="-s -w -X github.com/loveuer/go-alived/internal/cmd.Version=${{ steps.version.outputs.VERSION }}" \
+            -o dist/${BINARY_NAME} .
+          
+          # Create checksum
+          cd dist && sha256sum ${BINARY_NAME} > ${BINARY_NAME}.sha256
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: go-alived-${{ matrix.os }}-${{ matrix.arch }}
+          path: dist/
+
+  release:
+    name: Create Release
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Download all artifacts
+        uses: actions/download-artifact@v4
+        with:
+          path: artifacts
+
+      - name: Prepare release files
+        run: |
+          mkdir -p release
+          find artifacts -type f -exec cp {} release/ \;
+          ls -la release/
+
+      - name: Get version
+        id: version
+        run: echo "VERSION=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
+
+      - name: Create Release
+        uses: softprops/action-gh-release@v1
+        with:
+          name: Release ${{ steps.version.outputs.VERSION }}
+          draft: false
+          prerelease: ${{ contains(github.ref, '-rc') || contains(github.ref, '-beta') || contains(github.ref, '-alpha') }}
+          generate_release_notes: true
+          files: release/*
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
--- a/README.md
+++ b/README.md
@@ -1,40 +1,35 @@
 # go-alived

-A lightweight, dependency-free VRRP (Virtual Router Redundancy Protocol) implementation in Go, designed as a simple alternative to keepalived.
+A lightweight VRRP (Virtual Router Redundancy Protocol) implementation in Go, designed as a simple alternative to keepalived.

 ## Features

-✅ **Phase 1: Core VRRP Functionality (Completed)**
- VRRP protocol implementation (RFC 3768/5798)
- Virtual IP management (add/remove VIPs)
- State machine (INIT/BACKUP/MASTER/FAULT)
- Priority-based master election
- Gratuitous ARP for network updates
- Raw socket VRRP packet send/receive
- Timer management (advertisement & master-down timers)
- VRRP instance manager with multi-instance support
- Configuration hot-reload (SIGHUP)
-
-✅ **Phase 2: Health Checking (Completed)**
- Health checker interface with rise/fall logic
- TCP health checks
- HTTP/HTTPS health checks
- ICMP ping checks
- Script-based checks (custom commands)
- Periodic health check scheduling
- Health check integration with VRRP priority
- Track scripts: automatic priority adjustment on health changes
-
-🚧 **Phase 3: Enhanced Features (Planned)**
- State transition scripts (notify_master/backup/fault)
- Email/Webhook notifications
- Sync groups
- Virtual MAC support
- Metrics export
+- **VRRP Protocol**: RFC 3768/5798 compliant implementation
+- **High Availability**: Automatic failover with priority-based master election
+- **Health Checking**: TCP, HTTP/HTTPS, ICMP ping, and script-based checks
+- **Easy Deployment**: Built-in install command with systemd/init.d support
+- **Hot Reload**: Configuration reload via SIGHUP without service restart
+- **Zero Dependencies**: Single static binary, no runtime dependencies

 ## Installation

-### Build from source
+### Download Binary
+
+Download the latest release from [GitHub Releases](https://github.com/loveuer/go-alived/releases):
+
+```bash
+# Linux amd64
+curl -LO https://github.com/loveuer/go-alived/releases/latest/download/go-alived-linux-amd64
+chmod +x go-alived-linux-amd64
+sudo mv go-alived-linux-amd64 /usr/local/bin/go-alived
+
+# Linux arm64
+curl -LO https://github.com/loveuer/go-alived/releases/latest/download/go-alived-linux-arm64
+chmod +x go-alived-linux-arm64
+sudo mv go-alived-linux-arm64 /usr/local/bin/go-alived
+```
+
+### Build from Source

 ```bash
 git clone https://github.com/loveuer/go-alived.git
@@ -42,190 +37,246 @@ cd go-alived
 go build -o go-alived .
 ```

+### Quick Install (Recommended)
+
+```bash
+# Install as systemd service (default)
+sudo ./go-alived install
+
+# Install as init.d service (for OpenWrt/older systems)
+sudo ./go-alived install --method service
+```
+
 ## Quick Start

-### 1. Test Your Environment
-
-Before deployment, test if your environment supports VRRP:
+### 1. Test Environment

 ```bash
-# Basic test (auto-detect network interface)
-sudo ./go-alived test
+# Check if your environment supports VRRP
+sudo go-alived test

-# Test specific interface
-sudo ./go-alived test -i eth0
-
-# Full test with VIP
-sudo ./go-alived test -i eth0 -v 192.168.1.100/24
+# Test with specific interface
+sudo go-alived test -i eth0
 ```

-### 2. Run the Service
+### 2. Configure
+
+Edit `/etc/go-alived/config.yaml`:
+
+```yaml
+global:
+  router_id: "node1"
+
+vrrp_instances:
+  - name: "VI_1"
+    interface: "eth0"          # Network interface
+    state: "BACKUP"            # Initial state
+    virtual_router_id: 51      # VRID (1-255, must match on all nodes)
+    priority: 100              # Higher = more likely to be master
+    advert_interval: 1         # Advertisement interval in seconds
+    auth_type: "PASS"          # Authentication type
+    auth_pass: "secret"        # Password (max 8 chars)
+    virtual_ips:
+      - "192.168.1.100/24"     # Virtual IP address(es)
+```
+
+### 3. Start Service

 ```bash
-# Run with minimal config
-sudo ./go-alived run -c config.mini.yaml -d
-
-# Run with full config
-sudo ./go-alived -c config.yaml
-
-# Install as systemd service
-sudo ./deployment/install.sh
+# Systemd
+sudo systemctl daemon-reload
+sudo systemctl enable go-alived
 sudo systemctl start go-alived
+
+# Init.d
+sudo /etc/init.d/go-alived start
 ```

-## Usage
+### 4. Verify

-### Commands
+```bash
+# Check service status
+sudo systemctl status go-alived

+# Check VIP
+ip addr show eth0 | grep 192.168.1.100
+
+# View logs
+sudo journalctl -u go-alived -f
 ```
-go-alived              # Run VRRP service (default)
-go-alived run          # Run VRRP service
-go-alived test         # Test environment for VRRP support
-go-alived --help       # Show help
-go-alived --version    # Show version
-```
-
-### Global Flags
-
-```
-c, --config string    Path to configuration file (default "/etc/go-alived/config.yaml")
-d, --debug            Enable debug mode
-h, --help             Show help
-v, --version          Show version
-```
-
-### Test Command Flags
-
-```
-i, --interface string    Network interface to test (auto-detect if not specified)
-v, --vip string          Test VIP address (e.g., 192.168.1.100/24)
-```
-
-See [USAGE.md](USAGE.md) for detailed usage documentation.

 ## Configuration

-### Minimal Configuration
+### Two-Node HA Setup Example

+**Node 1 (Primary)**:
 ```yaml
-# config.mini.yaml - VRRP only
 global:
  router_id: "node1"

 vrrp_instances:
  - name: "VI_1"
    interface: "eth0"
-    state: "BACKUP"
+    state: "MASTER"
    virtual_router_id: 51
-    priority: 100
+    priority: 100              # Higher priority
    advert_interval: 1
    auth_type: "PASS"
-    auth_pass: "secret123"
+    auth_pass: "secret"
    virtual_ips:
      - "192.168.1.100/24"
 ```

-### Full Configuration Example
+**Node 2 (Backup)**:
+```yaml
+global:
+  router_id: "node2"

-See `config.example.yaml` for complete configuration with health checking.
+vrrp_instances:
+  - name: "VI_1"
+    interface: "eth0"
+    state: "BACKUP"
+    virtual_router_id: 51
+    priority: 90               # Lower priority
+    advert_interval: 1
+    auth_type: "PASS"
+    auth_pass: "secret"        # Must match
+    virtual_ips:
+      - "192.168.1.100/24"     # Must match
+```

-### Signals
+### Health Checking

- `SIGHUP`: Reload configuration
- `SIGINT/SIGTERM`: Graceful shutdown
+```yaml
+vrrp_instances:
+  - name: "VI_1"
+    # ... other settings ...
+    track_scripts:
+      - "check_nginx"          # Reference to health checker

-## Architecture
+health_checkers:
+  - name: "check_nginx"
+    type: "tcp"
+    interval: 3s
+    timeout: 2s
+    rise: 3                    # Successes to mark healthy
+    fall: 2                    # Failures to mark unhealthy
+    config:
+      host: "127.0.0.1"
+      port: 80
+```
+
+**Supported Health Check Types**:
+
+| Type | Description | Config |
+|------|-------------|--------|
+| `tcp` | TCP port check | `host`, `port` |
+| `http` | HTTP endpoint check | `url`, `method`, `expected_status` |
+| `ping` | ICMP ping check | `host`, `count` |
+| `script` | Custom script | `script`, `args` |
+
+## Commands

 ```
-go-alived/
-├── main.go                 # Application entry point
-├── internal/
-│   ├── cmd/               # Cobra commands
-│   │   ├── root.go        # Root command
-│   │   ├── run.go         # Run service command
-│   │   └── test.go        # Environment test command
-│   ├── vrrp/              # VRRP implementation
-│   │   ├── packet.go      # VRRP packet structure & marshaling
-│   │   ├── socket.go      # Raw socket operations
-│   │   ├── state.go       # State machine & timers
-│   │   ├── arp.go         # Gratuitous ARP
-│   │   ├── instance.go    # VRRP instance logic
-│   │   └── manager.go     # Instance manager
-│   └── health/            # Health check system
-│       ├── checker.go     # Checker interface & state
-│       ├── monitor.go     # Health check scheduler
-│       ├── tcp.go         # TCP health checker
-│       ├── http.go        # HTTP/HTTPS health checker
-│       ├── ping.go        # ICMP ping checker
-│       ├── script.go      # Script checker
-│       └── factory.go     # Checker factory
-├── pkg/
-│   ├── config/            # Configuration loading & validation
-│   ├── logger/            # Logging system
-│   └── netif/             # Network interface management
-└── deployment/            # Deployment files
-    ├── go-alived.service  # Systemd service file
-    ├── install.sh         # Installation script
-    ├── uninstall.sh       # Uninstallation script
-    ├── check-env.sh       # Environment check script
-    ├── README.md          # Deployment documentation
-    └── COMPATIBILITY.md   # Environment compatibility guide
+go-alived [command]
+
+Available Commands:
+  run         Run the VRRP service
+  test        Test environment for VRRP support
+  install     Install go-alived as a system service (alias: i)
+  help        Help about any command
+
+Flags:
+  -h, --help      help for go-alived
+  -v, --version   version for go-alived
+```
+
+### run
+
+```bash
+go-alived run [flags]
+
+Flags:
+  -c, --config string   Path to config file (default "/etc/go-alived/config.yaml")
+  -d, --debug           Enable debug mode
+```
+
+### test
+
+```bash
+go-alived test [flags]
+
+Flags:
+  -i, --interface string   Network interface to test
+  -v, --vip string         Test VIP address (e.g., 192.168.1.100/24)
+```
+
+### install
+
+```bash
+go-alived install [flags]
+
+Flags:
+  -m, --method string   Installation method: systemd, service (default "systemd")
+
+Aliases:
+  install, i
+```
+
+## Signals
+
+| Signal | Action |
+|--------|--------|
+| `SIGHUP` | Reload configuration |
+| `SIGINT` / `SIGTERM` | Graceful shutdown |
+
+```bash
+# Reload configuration
+sudo kill -HUP $(pgrep go-alived)
 ```

 ## Environment Compatibility

-### ✅ Fully Supported
- Physical servers
- KVM/QEMU virtual machines
- Proxmox VE
- VMware ESXi (with promiscuous mode)
- VirtualBox (with bridged network + promiscuous mode)
+| Environment | Support | Notes |
+|-------------|---------|-------|
+| Physical servers | Full | |
+| KVM/QEMU/Proxmox | Full | |
+| VMware ESXi | Full | Enable promiscuous mode |
+| VirtualBox | Full | Bridged network + promiscuous mode |
+| Docker | Limited | Requires `--privileged --net=host` |
+| OpenWrt/iStoreOS | Full | Use `--method service` for install |
+| AWS/Aliyun/Azure | None | Multicast disabled |

-### ⚠️ Limited Support
- Private cloud (depends on network configuration)
- Docker containers (requires `--privileged` and `--net=host`)
- Kubernetes (requires hostNetwork mode)
+> **Note**: VRRP requires multicast support (224.0.0.18). Most public clouds disable multicast at the network layer. Use cloud-native HA solutions instead.

-### ❌ Not Supported
- AWS EC2 (multicast disabled)
- Aliyun ECS (multicast disabled)
- Azure VM (requires special configuration)
- Google Cloud (multicast disabled by default)
+## Troubleshooting

-**Why?** Public clouds typically disable multicast protocols (224.0.0.18) at the network virtualization layer.
+### Common Issues

-**Alternative**: Use cloud-native solutions like Elastic IP (AWS), SLB/HaVip (Aliyun), Load Balancer (Azure/GCP).
+**1. "permission denied" or "operation not permitted"**
+```bash
+# VRRP requires root privileges
+sudo go-alived run -c /etc/go-alived/config.yaml
+```

-See [deployment/COMPATIBILITY.md](deployment/COMPATIBILITY.md) for detailed compatibility information.
+**2. "authentication failed"**
+- Ensure `auth_pass` matches on all nodes
+- Password is limited to 8 characters

-## Requirements
+**3. Both nodes become MASTER (split-brain)**
+- Check network connectivity between nodes
+- Verify `virtual_router_id` matches
+- Ensure multicast traffic is allowed

- Go 1.21+ (for building)
- Linux/macOS with root privileges (for raw sockets and interface management)
- Network interface with IPv4 address
- Multicast support (for VRRP)
+**4. VIP not pingable after failover**
+- Gratuitous ARP may be blocked
+- Check switch/router ARP cache timeout

-## Dependencies
+### Debug Mode

-Minimal external dependencies:
- `github.com/vishvananda/netlink` - Network interface management
- `github.com/mdlayher/arp` - ARP packet handling
- `github.com/spf13/cobra` - CLI framework
- `golang.org/x/net/ipv4` - IPv4 raw socket support
- `golang.org/x/net/icmp` - ICMP ping support
- `gopkg.in/yaml.v3` - YAML configuration parsing
-
-## Documentation
-
- [USAGE.md](USAGE.md) - Detailed usage guide
- [TESTING.md](TESTING.md) - Testing guide
- [deployment/README.md](deployment/README.md) - Deployment guide
- [deployment/COMPATIBILITY.md](deployment/COMPATIBILITY.md) - Environment compatibility
- [roadmap.md](roadmap.md) - Implementation roadmap
-
-## Roadmap
-
-See [roadmap.md](roadmap.md) for detailed implementation plan.
+```bash
+sudo go-alived run -c /etc/go-alived/config.yaml -d
+```

 ## License

--- a/go.mod
+++ b/go.mod
@@ -1,20 +1,23 @@
 module github.com/loveuer/go-alived

-go 1.25.0
+go 1.24.0
+
+require (
+	github.com/mdlayher/arp v0.0.0-20220512170110-6706a2966875
+	github.com/spf13/cobra v1.10.2
+	github.com/vishvananda/netlink v1.3.1
+	golang.org/x/net v0.47.0
+	gopkg.in/yaml.v3 v3.0.1
+)

 require (
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/josharian/native v1.0.0 // indirect
-	github.com/mdlayher/arp v0.0.0-20220512170110-6706a2966875 // indirect
 	github.com/mdlayher/ethernet v0.0.0-20220221185849-529eae5b6118 // indirect
 	github.com/mdlayher/packet v1.0.0 // indirect
 	github.com/mdlayher/socket v0.2.1 // indirect
-	github.com/spf13/cobra v1.10.2 // indirect
 	github.com/spf13/pflag v1.0.9 // indirect
-	github.com/vishvananda/netlink v1.3.1 // indirect
 	github.com/vishvananda/netns v0.0.5 // indirect
-	golang.org/x/net v0.47.0 // indirect
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
 	golang.org/x/sys v0.38.0 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,6 @@
 github.com/cpuguy83/go-md2man/v2 v2.0.6/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=
 github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.7 h1:81/ik6ipDQS2aGcBfIN5dHDB36BwrStyeAQquSYCV4o=
 github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
@@ -25,7 +26,6 @@ github.com/vishvananda/netns v0.0.5/go.mod h1:SpkAiCQRtJ6TvvxPnOSyH3BMl6unz3xZla
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/net v0.0.0-20190503192946-f4e77d36d62c/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190603091049-60506f45cf65 h1:+rhAzEzT3f4JtomfC371qB+0Ola2caSKcY69NUBZrRQ=
 golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
 golang.org/x/net v0.47.0 h1:Mx+4dIFzqraBXUugkia1OOvlD6LemFo1ALMHjrXDOhY=
 golang.org/x/net v0.47.0/go.mod h1:/jNxtkgq5yWUGYkaZGqo27cfGZ1c5Nen03aYrrKpVRU=
@@ -35,12 +35,12 @@ golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.10.0 h1:SqMFp9UcQJZa+pmYuAKjd9xq1f0j5rLcDIk0mj4qAsA=
 golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
 golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
--- a/internal/cmd/install.go
+++ b/internal/cmd/install.go
@@ -0,0 +1,466 @@
+package cmd
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/spf13/cobra"
+)
+
+const (
+	defaultBinaryPath  = "/usr/local/bin/go-alived"
+	defaultConfigDir   = "/etc/go-alived"
+	defaultConfigFile  = "/etc/go-alived/config.yaml"
+	systemdServicePath = "/etc/systemd/system/go-alived.service"
+	initdScriptPath    = "/etc/init.d/go-alived"
+)
+
+var (
+	installMethod string
+)
+
+var installCmd = &cobra.Command{
+	Use:     "install",
+	Aliases: []string{"i"},
+	Short:   "Install go-alived as a system service",
+	Long: `Install go-alived binary and configuration files to system paths.
+
+Supported installation methods:
+  - systemd: Install as a systemd service (default, recommended for modern Linux)
+  - service: Install as a SysV init.d service (for older Linux distributions)
+
+Examples:
+  sudo go-alived install
+  sudo go-alived install --method systemd
+  sudo go-alived i -m service`,
+	Run: runInstall,
+}
+
+func init() {
+	rootCmd.AddCommand(installCmd)
+
+	installCmd.Flags().StringVarP(&installMethod, "method", "m", "systemd",
+		"installation method: systemd, service")
+}
+
+func runInstall(cmd *cobra.Command, args []string) {
+	// Check root privileges
+	if os.Geteuid() != 0 {
+		fmt.Println("Error: This command requires root privileges")
+		fmt.Println("Please run with: sudo go-alived install")
+		os.Exit(1)
+	}
+
+	// Validate method
+	method := strings.ToLower(installMethod)
+	if method != "systemd" && method != "service" {
+		fmt.Printf("Error: Invalid installation method '%s'\n", installMethod)
+		fmt.Println("Supported methods: systemd, service")
+		os.Exit(1)
+	}
+
+	fmt.Println("=== Go-Alived Installation ===")
+	fmt.Println()
+
+	const totalSteps = 3
+
+	// Step 1: Copy binary
+	if err := installBinary(1, totalSteps); err != nil {
+		fmt.Printf("Error installing binary: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Step 2: Create config directory and file
+	configCreated, err := installConfig(2, totalSteps)
+	if err != nil {
+		fmt.Printf("Error installing config: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Step 3: Install service script
+	if err := installServiceScript(3, totalSteps, method); err != nil {
+		fmt.Printf("Error installing service script: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Print completion message
+	printCompletionMessage(method, configCreated)
+}
+
+func installBinary(step, total int) error {
+	fmt.Printf("[%d/%d] Installing binary... ", step, total)
+
+	// Get current executable path
+	execPath, err := os.Executable()
+	if err != nil {
+		return fmt.Errorf("failed to get executable path: %w", err)
+	}
+
+	// Resolve symlinks
+	execPath, err = filepath.EvalSymlinks(execPath)
+	if err != nil {
+		return fmt.Errorf("failed to resolve symlinks: %w", err)
+	}
+
+	// Check if already installed at target path
+	if execPath == defaultBinaryPath {
+		fmt.Println("already installed")
+		return nil
+	}
+
+	// Open source file
+	src, err := os.Open(execPath)
+	if err != nil {
+		return fmt.Errorf("failed to open source binary: %w", err)
+	}
+	defer src.Close()
+
+	// Create destination file
+	dst, err := os.OpenFile(defaultBinaryPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0755)
+	if err != nil {
+		return fmt.Errorf("failed to create destination binary: %w", err)
+	}
+	defer dst.Close()
+
+	// Copy binary
+	if _, err := io.Copy(dst, src); err != nil {
+		return fmt.Errorf("failed to copy binary: %w", err)
+	}
+
+	fmt.Printf("done (%s)\n", defaultBinaryPath)
+	return nil
+}
+
+func installConfig(step, total int) (bool, error) {
+	fmt.Printf("[%d/%d] Setting up configuration... ", step, total)
+
+	// Create config directory
+	if err := os.MkdirAll(defaultConfigDir, 0755); err != nil {
+		return false, fmt.Errorf("failed to create config directory: %w", err)
+	}
+
+	// Check if config file already exists
+	if _, err := os.Stat(defaultConfigFile); err == nil {
+		fmt.Println("config already exists")
+		return false, nil
+	}
+
+	// Generate config content
+	configContent := generateDefaultConfig()
+
+	// Write config file
+	if err := os.WriteFile(defaultConfigFile, []byte(configContent), 0644); err != nil {
+		return false, fmt.Errorf("failed to write config file: %w", err)
+	}
+
+	fmt.Printf("done (%s)\n", defaultConfigFile)
+	return true, nil
+}
+
+func installServiceScript(step, total int, method string) error {
+	switch method {
+	case "systemd":
+		return installSystemdService(step, total)
+	case "service":
+		return installInitdScript(step, total)
+	default:
+		return fmt.Errorf("unsupported method: %s", method)
+	}
+}
+
+func installSystemdService(step, total int) error {
+	fmt.Printf("[%d/%d] Installing systemd service... ", step, total)
+
+	serviceContent := generateSystemdService()
+
+	if err := os.WriteFile(systemdServicePath, []byte(serviceContent), 0644); err != nil {
+		return fmt.Errorf("failed to write service file: %w", err)
+	}
+
+	fmt.Printf("done (%s)\n", systemdServicePath)
+	return nil
+}
+
+func installInitdScript(step, total int) error {
+	fmt.Printf("[%d/%d] Installing init.d script... ", step, total)
+
+	scriptContent := generateInitdScript()
+
+	if err := os.WriteFile(initdScriptPath, []byte(scriptContent), 0755); err != nil {
+		return fmt.Errorf("failed to write init.d script: %w", err)
+	}
+
+	fmt.Printf("done (%s)\n", initdScriptPath)
+	return nil
+}
+
+func generateDefaultConfig() string {
+	// Auto-detect network interface
+	iface := detectNetworkInterface()
+	hostname, _ := os.Hostname()
+	if hostname == "" {
+		hostname = "node1"
+	}
+
+	return fmt.Sprintf(`# Go-Alived Configuration
+# Generated by: go-alived install
+# Documentation: https://github.com/loveuer/go-alived
+
+global:
+  router_id: "%s"
+
+vrrp_instances:
+  - name: "VI_1"
+    interface: "%s"
+    state: "BACKUP"
+    virtual_router_id: 51
+    priority: 100
+    advert_interval: 1
+    auth_type: "PASS"
+    auth_pass: "changeme"    # TODO: Change this password
+    virtual_ips:
+      - "192.168.1.100/24"   # TODO: Change to your VIP
+
+# Optional: Health checkers
+# health_checkers:
+#   - name: "check_nginx"
+#     type: "tcp"
+#     interval: 3s
+#     timeout: 2s
+#     rise: 3
+#     fall: 2
+#     config:
+#       host: "127.0.0.1"
+#       port: 80
+`, hostname, iface)
+}
+
+func generateSystemdService() string {
+	return `[Unit]
+Description=Go-Alived - VRRP High Availability Service
+Documentation=https://github.com/loveuer/go-alived
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=simple
+User=root
+Group=root
+
+ExecStart=/usr/local/bin/go-alived run --config /etc/go-alived/config.yaml
+ExecReload=/bin/kill -HUP $MAINPID
+
+Restart=on-failure
+RestartSec=5s
+
+StandardOutput=journal
+StandardError=journal
+SyslogIdentifier=go-alived
+
+# Security settings
+NoNewPrivileges=false
+PrivateTmp=true
+ProtectSystem=strict
+ProtectHome=true
+ReadWritePaths=/etc/go-alived
+
+# Resource limits
+LimitNOFILE=65535
+LimitNPROC=512
+
+# Capabilities required for VRRP operations
+AmbientCapabilities=CAP_NET_ADMIN CAP_NET_RAW CAP_NET_BIND_SERVICE
+CapabilityBoundingSet=CAP_NET_ADMIN CAP_NET_RAW CAP_NET_BIND_SERVICE
+
+[Install]
+WantedBy=multi-user.target
+`
+}
+
+func generateInitdScript() string {
+	return `#!/bin/sh
+### BEGIN INIT INFO
+# Provides:          go-alived
+# Required-Start:    $network $remote_fs $syslog
+# Required-Stop:     $network $remote_fs $syslog
+# Default-Start:     2 3 4 5
+# Default-Stop:      0 1 6
+# Short-Description: Go-Alived VRRP High Availability Service
+# Description:       Lightweight VRRP implementation for IP high availability
+### END INIT INFO
+
+NAME="go-alived"
+DAEMON="/usr/local/bin/go-alived"
+DAEMON_ARGS="run --config /etc/go-alived/config.yaml"
+PIDFILE="/var/run/${NAME}.pid"
+LOGFILE="/var/log/${NAME}.log"
+
+[ -x "$DAEMON" ] || exit 5
+
+start() {
+    if [ -f "$PIDFILE" ] && kill -0 "$(cat "$PIDFILE")" 2>/dev/null; then
+        echo "$NAME is already running"
+        return 1
+    fi
+    echo -n "Starting $NAME... "
+    nohup $DAEMON $DAEMON_ARGS >> "$LOGFILE" 2>&1 &
+    echo $! > "$PIDFILE"
+    echo "done (PID: $(cat "$PIDFILE"))"
+}
+
+stop() {
+    if [ ! -f "$PIDFILE" ] || ! kill -0 "$(cat "$PIDFILE")" 2>/dev/null; then
+        echo "$NAME is not running"
+        return 1
+    fi
+    echo -n "Stopping $NAME... "
+    kill "$(cat "$PIDFILE")"
+    rm -f "$PIDFILE"
+    echo "done"
+}
+
+restart() {
+    stop
+    sleep 1
+    start
+}
+
+reload() {
+    if [ ! -f "$PIDFILE" ] || ! kill -0 "$(cat "$PIDFILE")" 2>/dev/null; then
+        echo "$NAME is not running"
+        return 1
+    fi
+    echo -n "Reloading $NAME configuration... "
+    kill -HUP "$(cat "$PIDFILE")"
+    echo "done"
+}
+
+status() {
+    if [ -f "$PIDFILE" ] && kill -0 "$(cat "$PIDFILE")" 2>/dev/null; then
+        echo "$NAME is running (PID: $(cat "$PIDFILE"))"
+    else
+        echo "$NAME is not running"
+        [ -f "$PIDFILE" ] && rm -f "$PIDFILE"
+        return 1
+    fi
+}
+
+case "$1" in
+    start)   start   ;;
+    stop)    stop    ;;
+    restart) restart ;;
+    reload)  reload  ;;
+    status)  status  ;;
+    *)
+        echo "Usage: $0 {start|stop|restart|reload|status}"
+        exit 2
+        ;;
+esac
+
+exit $?
+`
+}
+
+func detectNetworkInterface() string {
+	interfaces, err := net.Interfaces()
+	if err != nil {
+		return "eth0"
+	}
+
+	for _, iface := range interfaces {
+		// Skip loopback and down interfaces
+		if iface.Flags&net.FlagLoopback != 0 {
+			continue
+		}
+		if iface.Flags&net.FlagUp == 0 {
+			continue
+		}
+
+		// Check if interface has IPv4 address
+		addrs, err := iface.Addrs()
+		if err != nil {
+			continue
+		}
+
+		for _, addr := range addrs {
+			if ipNet, ok := addr.(*net.IPNet); ok {
+				if ipv4 := ipNet.IP.To4(); ipv4 != nil && !ipv4.IsLoopback() {
+					return iface.Name
+				}
+			}
+		}
+	}
+
+	return "eth0"
+}
+
+func printCompletionMessage(method string, configCreated bool) {
+	fmt.Println()
+	fmt.Println("=== Installation Complete ===")
+	fmt.Println()
+
+	// Installed files summary
+	fmt.Println(">>> Installed Files:")
+	fmt.Printf("    Binary:  %s\n", defaultBinaryPath)
+	fmt.Printf("    Config:  %s\n", defaultConfigFile)
+	if method == "systemd" {
+		fmt.Printf("    Service: %s\n", systemdServicePath)
+	} else {
+		fmt.Printf("    Service: %s\n", initdScriptPath)
+	}
+	fmt.Println()
+
+	// What needs to be modified
+	fmt.Println(">>> Configuration Required:")
+	fmt.Printf("    Edit: %s\n", defaultConfigFile)
+	fmt.Println()
+	if configCreated {
+		fmt.Println("    Modify the following settings:")
+		fmt.Println("    - auth_pass:    Change 'changeme' to a secure password")
+		fmt.Println("    - virtual_ips:  Set your Virtual IP address(es)")
+		fmt.Println("    - interface:    Verify the network interface is correct")
+		fmt.Println("    - priority:     Adjust based on node role (higher = more likely master)")
+	} else {
+		fmt.Println("    Review your existing configuration")
+	}
+	fmt.Println()
+
+	// How to start
+	fmt.Println(">>> Next Steps:")
+	if method == "systemd" {
+		fmt.Println("    1. Edit configuration:")
+		fmt.Printf("       sudo vim %s\n", defaultConfigFile)
+		fmt.Println()
+		fmt.Println("    2. Reload systemd and start service:")
+		fmt.Println("       sudo systemctl daemon-reload")
+		fmt.Println("       sudo systemctl enable go-alived")
+		fmt.Println("       sudo systemctl start go-alived")
+		fmt.Println()
+		fmt.Println("    3. Check service status:")
+		fmt.Println("       sudo systemctl status go-alived")
+		fmt.Println("       sudo journalctl -u go-alived -f")
+	} else {
+		fmt.Println("    1. Edit configuration:")
+		fmt.Printf("       sudo vim %s\n", defaultConfigFile)
+		fmt.Println()
+		fmt.Println("    2. Start service:")
+		fmt.Printf("       sudo %s start\n", initdScriptPath)
+		fmt.Println()
+		fmt.Println("    3. Enable on boot (Debian/Ubuntu):")
+		fmt.Println("       sudo update-rc.d go-alived defaults")
+		fmt.Println()
+		fmt.Println("    4. Check service status:")
+		fmt.Printf("       sudo %s status\n", initdScriptPath)
+		fmt.Printf("       tail -f /var/log/go-alived.log\n")
+	}
+	fmt.Println()
+
+	// Test environment
+	fmt.Println(">>> Test Environment (Optional):")
+	fmt.Printf("    sudo %s test\n", defaultBinaryPath)
+	fmt.Println()
+}
--- a/internal/cmd/root.go
+++ b/internal/cmd/root.go
@@ -6,12 +6,14 @@ import (
 	"github.com/spf13/cobra"
 )

+// Version can be set at build time via ldflags
+var Version = "1.2.1"
+
 var rootCmd = &cobra.Command{
 	Use:   "go-alived",
 	Short: "Go-Alived - VRRP High Availability Service",
 	Long: `go-alived is a lightweight, dependency-free VRRP implementation in Go.
 It provides high availability for IP addresses with health checking support.`,
-	Version: "1.0.0",
 }

 func Execute() {
@@ -21,5 +23,6 @@ func Execute() {
 }

 func init() {
+	rootCmd.Version = Version
 	rootCmd.CompletionOptions.DisableDefaultCmd = true
 }
--- a/internal/cmd/test.go
+++ b/internal/cmd/test.go
@@ -367,7 +367,7 @@ func (t *EnvironmentTest) TestCloudEnvironment() {
 		if err == nil {
 			cloudDetected = true
 			t.AddResult("云环境", !test.isFatal, fmt.Sprintf("检测到%s环境", test.name), test.isFatal)
-			t.log.Warn(test.solution)
+			t.log.Warn("%s", test.solution)
 		}
 	}

--- a/internal/health/factory.go
+++ b/internal/health/factory.go
@@ -8,9 +8,13 @@ import (
 )

 func CreateChecker(cfg *config.HealthChecker) (Checker, error) {
+	if cfg.Config == nil {
+		return nil, fmt.Errorf("missing config for checker %s", cfg.Name)
+	}
+
 	configMap, ok := cfg.Config.(map[string]interface{})
 	if !ok {
-		return nil, fmt.Errorf("invalid config for checker %s", cfg.Name)
+		return nil, fmt.Errorf("invalid config type for checker %s: expected map[string]interface{}", cfg.Name)
 	}

 	switch cfg.Type {
@@ -36,6 +40,7 @@ func LoadFromConfig(cfg *config.Config, log *logger.Logger) (*Manager, error) {
 			return nil, fmt.Errorf("failed to create checker %s: %w", healthCfg.Name, err)
 		}

+		configMap, _ := healthCfg.Config.(map[string]interface{})
 		monitorCfg := &CheckerConfig{
 			Name:     healthCfg.Name,
 			Type:     healthCfg.Type,
@@ -43,7 +48,7 @@ func LoadFromConfig(cfg *config.Config, log *logger.Logger) (*Manager, error) {
 			Timeout:  healthCfg.Timeout,
 			Rise:     healthCfg.Rise,
 			Fall:     healthCfg.Fall,
-			Config:   healthCfg.Config.(map[string]interface{}),
+			Config:   configMap,
 		}

 		monitor := NewMonitor(checker, monitorCfg, log)
--- a/internal/health/manager.go
+++ b/internal/health/manager.go
@@ -0,0 +1,74 @@
+package health
+
+import (
+	"sync"
+
+	"github.com/loveuer/go-alived/pkg/logger"
+)
+
+// Manager manages multiple health check monitors.
+type Manager struct {
+	monitors map[string]*Monitor
+	mu       sync.RWMutex
+	log      *logger.Logger
+}
+
+// NewManager creates a new health check Manager.
+func NewManager(log *logger.Logger) *Manager {
+	return &Manager{
+		monitors: make(map[string]*Monitor),
+		log:      log,
+	}
+}
+
+// AddMonitor adds a monitor to the manager.
+func (m *Manager) AddMonitor(monitor *Monitor) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.monitors[monitor.config.Name] = monitor
+}
+
+// GetMonitor retrieves a monitor by name.
+func (m *Manager) GetMonitor(name string) (*Monitor, bool) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	monitor, ok := m.monitors[name]
+	return monitor, ok
+}
+
+// StartAll starts all registered monitors.
+func (m *Manager) StartAll() {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	for _, monitor := range m.monitors {
+		monitor.Start()
+	}
+
+	m.log.Info("started %d health check monitor(s)", len(m.monitors))
+}
+
+// StopAll stops all registered monitors.
+func (m *Manager) StopAll() {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	for _, monitor := range m.monitors {
+		monitor.Stop()
+	}
+
+	m.log.Info("stopped all health check monitors")
+}
+
+// GetAllStates returns the current state of all monitors.
+func (m *Manager) GetAllStates() map[string]*CheckerState {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	states := make(map[string]*CheckerState)
+	for name, monitor := range m.monitors {
+		states[name] = monitor.GetState()
+	}
+
+	return states
+}
--- a/internal/health/monitor.go
+++ b/internal/health/monitor.go
@@ -8,6 +8,7 @@ import (
 	"github.com/loveuer/go-alived/pkg/logger"
 )

+// Monitor runs periodic health checks and tracks state.
 type Monitor struct {
 	checker   Checker
 	config    *CheckerConfig
@@ -21,6 +22,7 @@ type Monitor struct {
 	mu      sync.RWMutex
 }

+// NewMonitor creates a new Monitor for the given checker.
 func NewMonitor(checker Checker, config *CheckerConfig, log *logger.Logger) *Monitor {
 	return &Monitor{
 		checker: checker,
@@ -35,6 +37,7 @@ func NewMonitor(checker Checker, config *CheckerConfig, log *logger.Logger) *Mon
 	}
 }

+// Start begins the health check loop.
 func (m *Monitor) Start() {
 	m.mu.Lock()
 	if m.running {
@@ -51,6 +54,7 @@ func (m *Monitor) Start() {
 	go m.checkLoop()
 }

+// Stop stops the health check loop.
 func (m *Monitor) Stop() {
 	m.mu.Lock()
 	if !m.running {
@@ -71,6 +75,7 @@ func (m *Monitor) checkLoop() {
 	ticker := time.NewTicker(m.config.Interval)
 	defer ticker.Stop()

+	// Perform initial check immediately
 	m.performCheck()

 	for {
@@ -95,7 +100,8 @@ func (m *Monitor) performCheck() {
 	oldHealthy := m.state.Healthy
 	stateChanged := m.state.Update(result, m.config.Rise, m.config.Fall)
 	newHealthy := m.state.Healthy
-	callbacks := m.callbacks
+	callbacks := make([]StateChangeCallback, len(m.callbacks))
+	copy(callbacks, m.callbacks)
 	m.mu.Unlock()

 	m.log.Debug("[HealthCheck:%s] check completed: result=%s, duration=%s, healthy=%v",
@@ -111,12 +117,14 @@ func (m *Monitor) performCheck() {
 	}
 }

+// OnStateChange registers a callback for health state changes.
 func (m *Monitor) OnStateChange(callback StateChangeCallback) {
 	m.mu.Lock()
 	defer m.mu.Unlock()
 	m.callbacks = append(m.callbacks, callback)
 }

+// GetState returns a copy of the current checker state.
 func (m *Monitor) GetState() *CheckerState {
 	m.mu.RLock()
 	defer m.mu.RUnlock()
@@ -125,68 +133,9 @@ func (m *Monitor) GetState() *CheckerState {
 	return &stateCopy
 }

+// IsHealthy returns whether the checker is currently healthy.
 func (m *Monitor) IsHealthy() bool {
 	m.mu.RLock()
 	defer m.mu.RUnlock()
 	return m.state.Healthy
 }
-
-type Manager struct {
-	monitors map[string]*Monitor
-	mu       sync.RWMutex
-	log      *logger.Logger
-}
-
-func NewManager(log *logger.Logger) *Manager {
-	return &Manager{
-		monitors: make(map[string]*Monitor),
-		log:      log,
-	}
-}
-
-func (m *Manager) AddMonitor(monitor *Monitor) {
-	m.mu.Lock()
-	defer m.mu.Unlock()
-	m.monitors[monitor.config.Name] = monitor
-}
-
-func (m *Manager) GetMonitor(name string) (*Monitor, bool) {
-	m.mu.RLock()
-	defer m.mu.RUnlock()
-	monitor, ok := m.monitors[name]
-	return monitor, ok
-}
-
-func (m *Manager) StartAll() {
-	m.mu.RLock()
-	defer m.mu.RUnlock()
-
-	for _, monitor := range m.monitors {
-		monitor.Start()
-	}
-
-	m.log.Info("started %d health check monitor(s)", len(m.monitors))
-}
-
-func (m *Manager) StopAll() {
-	m.mu.RLock()
-	defer m.mu.RUnlock()
-
-	for _, monitor := range m.monitors {
-		monitor.Stop()
-	}
-
-	m.log.Info("stopped all health check monitors")
-}
-
-func (m *Manager) GetAllStates() map[string]*CheckerState {
-	m.mu.RLock()
-	defer m.mu.RUnlock()
-
-	states := make(map[string]*CheckerState)
-	for name, monitor := range m.monitors {
-		states[name] = monitor.GetState()
-	}
-
-	return states
-}
--- a/internal/vrrp/history.go
+++ b/internal/vrrp/history.go
@@ -0,0 +1,95 @@
+package vrrp
+
+import (
+	"fmt"
+	"sync"
+	"time"
+)
+
+// StateTransition represents a single state transition event.
+type StateTransition struct {
+	From      State
+	To        State
+	Timestamp time.Time
+	Reason    string
+}
+
+// StateHistory maintains a bounded history of state transitions.
+type StateHistory struct {
+	transitions []StateTransition
+	maxSize     int
+	mu          sync.RWMutex
+}
+
+// NewStateHistory creates a new StateHistory with the specified maximum size.
+func NewStateHistory(maxSize int) *StateHistory {
+	return &StateHistory{
+		transitions: make([]StateTransition, 0, maxSize),
+		maxSize:     maxSize,
+	}
+}
+
+// Add records a new state transition.
+func (sh *StateHistory) Add(from, to State, reason string) {
+	sh.mu.Lock()
+	defer sh.mu.Unlock()
+
+	transition := StateTransition{
+		From:      from,
+		To:        to,
+		Timestamp: time.Now(),
+		Reason:    reason,
+	}
+
+	sh.transitions = append(sh.transitions, transition)
+
+	// Maintain bounded size using ring buffer style
+	if len(sh.transitions) > sh.maxSize {
+		// Copy to new slice to allow garbage collection of old backing array
+		newTransitions := make([]StateTransition, len(sh.transitions)-1, sh.maxSize)
+		copy(newTransitions, sh.transitions[1:])
+		sh.transitions = newTransitions
+	}
+}
+
+// GetRecent returns the most recent n transitions.
+func (sh *StateHistory) GetRecent(n int) []StateTransition {
+	sh.mu.RLock()
+	defer sh.mu.RUnlock()
+
+	if n > len(sh.transitions) {
+		n = len(sh.transitions)
+	}
+
+	start := len(sh.transitions) - n
+	result := make([]StateTransition, n)
+	copy(result, sh.transitions[start:])
+
+	return result
+}
+
+// Len returns the number of recorded transitions.
+func (sh *StateHistory) Len() int {
+	sh.mu.RLock()
+	defer sh.mu.RUnlock()
+	return len(sh.transitions)
+}
+
+// String returns a formatted string representation of the history.
+func (sh *StateHistory) String() string {
+	sh.mu.RLock()
+	defer sh.mu.RUnlock()
+
+	if len(sh.transitions) == 0 {
+		return "No state transitions"
+	}
+
+	result := "State transition history:\n"
+	for _, t := range sh.transitions {
+		result += fmt.Sprintf("  %s: %s -> %s (%s)\n",
+			t.Timestamp.Format("2006-01-02 15:04:05"),
+			t.From, t.To, t.Reason)
+	}
+
+	return result
+}
--- a/internal/vrrp/instance.go
+++ b/internal/vrrp/instance.go
@@ -17,6 +17,7 @@ type Instance struct {
 	AdvertInterval  uint8
 	Interface       string
 	VirtualIPs      []net.IP
+	VirtualIPCIDRs  []string // preserve original CIDR notation
 	AuthType        uint8
 	AuthPass        string
 	TrackScripts    []string
@@ -64,12 +65,14 @@ func NewInstance(
 	}

 	virtualIPs := make([]net.IP, 0, len(vips))
+	virtualIPCIDRs := make([]string, 0, len(vips))
 	for _, vip := range vips {
 		ip, _, err := net.ParseCIDR(vip)
 		if err != nil {
 			return nil, fmt.Errorf("invalid VIP %s: %w", vip, err)
 		}
 		virtualIPs = append(virtualIPs, ip)
+		virtualIPCIDRs = append(virtualIPCIDRs, vip)
 	}

 	var authTypeNum uint8
@@ -94,6 +97,7 @@ func NewInstance(
 		AdvertInterval:  advertInt,
 		Interface:       iface,
 		VirtualIPs:      virtualIPs,
+		VirtualIPCIDRs:  virtualIPCIDRs,
 		AuthType:        authTypeNum,
 		AuthPass:        authPass,
 		TrackScripts:    trackScripts,
@@ -192,8 +196,15 @@ func (inst *Instance) receiveLoop() {
 		default:
 		}

+		// Set read deadline to allow periodic check of stop channel
+		inst.socket.SetReadDeadline(time.Now().Add(100 * time.Millisecond))
+
 		pkt, srcIP, err := inst.socket.Receive()
 		if err != nil {
+			// Check if it's a timeout error, which is expected
+			if netErr, ok := err.(interface{ Timeout() bool }); ok && netErr.Timeout() {
+				continue
+			}
 			inst.log.Debug("[%s] failed to receive packet: %v", inst.Name, err)
 			continue
 		}
@@ -371,11 +382,7 @@ func (inst *Instance) removeVIPs() error {
 }

 func (inst *Instance) getVIPsWithCIDR() []string {
-	result := make([]string, len(inst.VirtualIPs))
-	for i, ip := range inst.VirtualIPs {
-		result[i] = ip.String() + "/32"
-	}
-	return result
+	return inst.VirtualIPCIDRs
 }

 func (inst *Instance) GetState() State {
@@ -399,15 +406,17 @@ func (inst *Instance) AdjustPriority(delta int) {
 	defer inst.mu.Unlock()

 	oldPriority := inst.priorityCalc.GetPriority()
-	
+
 	if delta < 0 {
 		inst.priorityCalc.DecreasePriority(uint8(-delta))
+	} else if delta > 0 {
+		inst.priorityCalc.IncreasePriority(uint8(delta))
 	}
-	
+
 	newPriority := inst.priorityCalc.GetPriority()
-	
+
 	if oldPriority != newPriority {
-		inst.log.Info("[%s] priority adjusted: %d -> %d (delta=%d)", 
+		inst.log.Info("[%s] priority adjusted: %d -> %d (delta=%d)",
 			inst.Name, oldPriority, newPriority, delta)
 	}
 }
--- a/internal/vrrp/priority.go
+++ b/internal/vrrp/priority.go
@@ -0,0 +1,99 @@
+package vrrp
+
+import (
+	"sync"
+	"time"
+)
+
+// PriorityCalculator manages VRRP priority with support for dynamic adjustment.
+type PriorityCalculator struct {
+	basePriority    uint8
+	currentPriority uint8
+	mu              sync.RWMutex
+}
+
+// NewPriorityCalculator creates a new PriorityCalculator with the specified base priority.
+func NewPriorityCalculator(basePriority uint8) *PriorityCalculator {
+	return &PriorityCalculator{
+		basePriority:    basePriority,
+		currentPriority: basePriority,
+	}
+}
+
+// GetPriority returns the current priority.
+func (pc *PriorityCalculator) GetPriority() uint8 {
+	pc.mu.RLock()
+	defer pc.mu.RUnlock()
+	return pc.currentPriority
+}
+
+// DecreasePriority decreases the current priority by the specified amount.
+// The priority will not go below 0.
+func (pc *PriorityCalculator) DecreasePriority(amount uint8) {
+	pc.mu.Lock()
+	defer pc.mu.Unlock()
+
+	if pc.currentPriority > amount {
+		pc.currentPriority -= amount
+	} else {
+		pc.currentPriority = 0
+	}
+}
+
+// IncreasePriority increases the current priority by the specified amount.
+// The priority will not exceed 255 or the base priority.
+func (pc *PriorityCalculator) IncreasePriority(amount uint8) {
+	pc.mu.Lock()
+	defer pc.mu.Unlock()
+
+	newPriority := pc.currentPriority + amount
+	if newPriority > pc.basePriority {
+		newPriority = pc.basePriority
+	}
+	if newPriority < pc.currentPriority { // overflow check
+		newPriority = pc.basePriority
+	}
+	pc.currentPriority = newPriority
+}
+
+// ResetPriority resets the priority to the base value.
+func (pc *PriorityCalculator) ResetPriority() {
+	pc.mu.Lock()
+	defer pc.mu.Unlock()
+	pc.currentPriority = pc.basePriority
+}
+
+// SetBasePriority sets a new base priority and resets current priority to match.
+func (pc *PriorityCalculator) SetBasePriority(priority uint8) {
+	pc.mu.Lock()
+	defer pc.mu.Unlock()
+	pc.basePriority = priority
+	pc.currentPriority = priority
+}
+
+// ShouldBecomeMaster determines if the local node should become master
+// based on priority comparison and IP address tie-breaking.
+func ShouldBecomeMaster(localPriority, remotePriority uint8, localIP, remoteIP string) bool {
+	if localPriority > remotePriority {
+		return true
+	}
+
+	if localPriority == remotePriority {
+		return localIP > remoteIP
+	}
+
+	return false
+}
+
+// CalculateMasterDownInterval calculates the master down interval
+// according to VRRP specification: (3 * Advertisement_Interval).
+func CalculateMasterDownInterval(advertInt uint8) time.Duration {
+	return time.Duration(3*int(advertInt)) * time.Second
+}
+
+// CalculateSkewTime calculates the skew time for master down timer
+// according to VRRP specification: ((256 - Priority) / 256).
+func CalculateSkewTime(priority uint8) time.Duration {
+	skew := float64(256-int(priority)) / 256.0
+	return time.Duration(skew * float64(time.Second))
+}
--- a/internal/vrrp/socket.go
+++ b/internal/vrrp/socket.go
@@ -5,6 +5,7 @@ import (
 	"net"
 	"os"
 	"syscall"
+	"time"

 	"golang.org/x/net/ipv4"
 )
@@ -14,10 +15,11 @@ const (
 )

 type Socket struct {
-	conn     *ipv4.RawConn
-	iface    *net.Interface
-	localIP  net.IP
-	groupIP  net.IP
+	conn       *ipv4.RawConn
+	packetConn net.PacketConn
+	iface      *net.Interface
+	localIP    net.IP
+	groupIP    net.IP
 }

 func NewSocket(ifaceName string) (*Socket, error) {
@@ -56,9 +58,8 @@ func NewSocket(ifaceName string) (*Socket, error) {
 	}

 	file := os.NewFile(uintptr(fd), "vrrp-socket")
-	defer file.Close()
-
 	packetConn, err := net.FilePacketConn(file)
+	file.Close()
 	if err != nil {
 		return nil, fmt.Errorf("failed to create packet connection: %w", err)
 	}
@@ -86,10 +87,11 @@ func NewSocket(ifaceName string) (*Socket, error) {
 	}

 	return &Socket{
-		conn:    rawConn,
-		iface:   iface,
-		localIP: localIP,
-		groupIP: groupIP,
+		conn:       rawConn,
+		packetConn: packetConn,
+		iface:      iface,
+		localIP:    localIP,
+		groupIP:    groupIP,
 	}, nil
 }

@@ -133,6 +135,10 @@ func (s *Socket) Receive() (*VRRPPacket, net.IP, error) {
 	return pkt, header.Src, nil
 }

+func (s *Socket) SetReadDeadline(t time.Time) error {
+	return s.packetConn.SetReadDeadline(t)
+}
+
 func (s *Socket) Close() error {
 	if err := s.conn.LeaveGroup(s.iface, &net.IPAddr{IP: s.groupIP}); err != nil {
 		return err
--- a/internal/vrrp/state.go
+++ b/internal/vrrp/state.go
@@ -1,11 +1,8 @@
 package vrrp

-import (
-	"fmt"
-	"sync"
-	"time"
-)
+import "sync"

+// State represents the VRRP instance state.
 type State int

 const (
@@ -15,6 +12,7 @@ const (
 	StateFault
 )

+// String returns the string representation of the state.
 func (s State) String() string {
 	switch s {
 	case StateInit:
@@ -30,33 +28,39 @@ func (s State) String() string {
 	}
 }

+// StateMachine manages VRRP state transitions with thread-safe callbacks.
 type StateMachine struct {
-	currentState     State
-	previousState    State
-	mu               sync.RWMutex
+	currentState         State
+	mu                   sync.RWMutex
 	stateChangeCallbacks []func(old, new State)
 }

+// NewStateMachine creates a new StateMachine with the specified initial state.
 func NewStateMachine(initialState State) *StateMachine {
 	return &StateMachine{
-		currentState:  initialState,
-		previousState: StateInit,
+		currentState:         initialState,
 		stateChangeCallbacks: make([]func(old, new State), 0),
 	}
 }

+// GetState returns the current state.
 func (sm *StateMachine) GetState() State {
 	sm.mu.RLock()
 	defer sm.mu.RUnlock()
 	return sm.currentState
 }

+// SetState transitions to a new state and triggers registered callbacks.
 func (sm *StateMachine) SetState(newState State) {
 	sm.mu.Lock()
 	oldState := sm.currentState
-	sm.previousState = oldState
+	if oldState == newState {
+		sm.mu.Unlock()
+		return
+	}
 	sm.currentState = newState
-	callbacks := sm.stateChangeCallbacks
+	callbacks := make([]func(old, new State), len(sm.stateChangeCallbacks))
+	copy(callbacks, sm.stateChangeCallbacks)
 	sm.mu.Unlock()

 	for _, callback := range callbacks {
@@ -64,195 +68,9 @@ func (sm *StateMachine) SetState(newState State) {
 	}
 }

+// OnStateChange registers a callback to be invoked on state changes.
 func (sm *StateMachine) OnStateChange(callback func(old, new State)) {
 	sm.mu.Lock()
 	defer sm.mu.Unlock()
 	sm.stateChangeCallbacks = append(sm.stateChangeCallbacks, callback)
 }
-
-type Timer struct {
-	duration time.Duration
-	timer    *time.Timer
-	callback func()
-	mu       sync.Mutex
-}
-
-func NewTimer(duration time.Duration, callback func()) *Timer {
-	return &Timer{
-		duration: duration,
-		callback: callback,
-	}
-}
-
-func (t *Timer) Start() {
-	t.mu.Lock()
-	defer t.mu.Unlock()
-
-	if t.timer != nil {
-		t.timer.Stop()
-	}
-
-	t.timer = time.AfterFunc(t.duration, t.callback)
-}
-
-func (t *Timer) Stop() {
-	t.mu.Lock()
-	defer t.mu.Unlock()
-
-	if t.timer != nil {
-		t.timer.Stop()
-		t.timer = nil
-	}
-}
-
-func (t *Timer) Reset() {
-	t.mu.Lock()
-	defer t.mu.Unlock()
-
-	if t.timer != nil {
-		t.timer.Stop()
-	}
-
-	t.timer = time.AfterFunc(t.duration, t.callback)
-}
-
-func (t *Timer) SetDuration(duration time.Duration) {
-	t.mu.Lock()
-	defer t.mu.Unlock()
-	t.duration = duration
-}
-
-type PriorityCalculator struct {
-	basePriority    uint8
-	currentPriority uint8
-	mu              sync.RWMutex
-}
-
-func NewPriorityCalculator(basePriority uint8) *PriorityCalculator {
-	return &PriorityCalculator{
-		basePriority:    basePriority,
-		currentPriority: basePriority,
-	}
-}
-
-func (pc *PriorityCalculator) GetPriority() uint8 {
-	pc.mu.RLock()
-	defer pc.mu.RUnlock()
-	return pc.currentPriority
-}
-
-func (pc *PriorityCalculator) DecreasePriority(amount uint8) {
-	pc.mu.Lock()
-	defer pc.mu.Unlock()
-
-	if pc.currentPriority > amount {
-		pc.currentPriority -= amount
-	} else {
-		pc.currentPriority = 0
-	}
-}
-
-func (pc *PriorityCalculator) ResetPriority() {
-	pc.mu.Lock()
-	defer pc.mu.Unlock()
-	pc.currentPriority = pc.basePriority
-}
-
-func (pc *PriorityCalculator) SetBasePriority(priority uint8) {
-	pc.mu.Lock()
-	defer pc.mu.Unlock()
-	pc.basePriority = priority
-	pc.currentPriority = priority
-}
-
-func ShouldBecomeMaster(localPriority, remotePriority uint8, localIP, remoteIP string) bool {
-	if localPriority > remotePriority {
-		return true
-	}
-
-	if localPriority == remotePriority {
-		return localIP > remoteIP
-	}
-
-	return false
-}
-
-func CalculateMasterDownInterval(advertInt uint8) time.Duration {
-	return time.Duration(3*int(advertInt)) * time.Second
-}
-
-func CalculateSkewTime(priority uint8) time.Duration {
-	skew := float64(256-int(priority)) / 256.0
-	return time.Duration(skew * float64(time.Second))
-}
-
-type StateTransition struct {
-	From      State
-	To        State
-	Timestamp time.Time
-	Reason    string
-}
-
-type StateHistory struct {
-	transitions []StateTransition
-	maxSize     int
-	mu          sync.RWMutex
-}
-
-func NewStateHistory(maxSize int) *StateHistory {
-	return &StateHistory{
-		transitions: make([]StateTransition, 0, maxSize),
-		maxSize:     maxSize,
-	}
-}
-
-func (sh *StateHistory) Add(from, to State, reason string) {
-	sh.mu.Lock()
-	defer sh.mu.Unlock()
-
-	transition := StateTransition{
-		From:      from,
-		To:        to,
-		Timestamp: time.Now(),
-		Reason:    reason,
-	}
-
-	sh.transitions = append(sh.transitions, transition)
-
-	if len(sh.transitions) > sh.maxSize {
-		sh.transitions = sh.transitions[1:]
-	}
-}
-
-func (sh *StateHistory) GetRecent(n int) []StateTransition {
-	sh.mu.RLock()
-	defer sh.mu.RUnlock()
-
-	if n > len(sh.transitions) {
-		n = len(sh.transitions)
-	}
-
-	start := len(sh.transitions) - n
-	result := make([]StateTransition, n)
-	copy(result, sh.transitions[start:])
-
-	return result
-}
-
-func (sh *StateHistory) String() string {
-	sh.mu.RLock()
-	defer sh.mu.RUnlock()
-
-	if len(sh.transitions) == 0 {
-		return "No state transitions"
-	}
-
-	result := "State transition history:\n"
-	for _, t := range sh.transitions {
-		result += fmt.Sprintf("  %s: %s -> %s (%s)\n",
-			t.Timestamp.Format("2006-01-02 15:04:05"),
-			t.From, t.To, t.Reason)
-	}
-
-	return result
-}
--- a/internal/vrrp/timer.go
+++ b/internal/vrrp/timer.go
@@ -0,0 +1,64 @@
+package vrrp
+
+import (
+	"sync"
+	"time"
+)
+
+// Timer provides a thread-safe timer with callback support.
+type Timer struct {
+	duration time.Duration
+	timer    *time.Timer
+	callback func()
+	mu       sync.Mutex
+}
+
+// NewTimer creates a new Timer with the specified duration and callback.
+func NewTimer(duration time.Duration, callback func()) *Timer {
+	return &Timer{
+		duration: duration,
+		callback: callback,
+	}
+}
+
+// Start starts or restarts the timer.
+func (t *Timer) Start() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	if t.timer != nil {
+		t.timer.Stop()
+	}
+
+	t.timer = time.AfterFunc(t.duration, t.callback)
+}
+
+// Stop stops the timer if it's running.
+func (t *Timer) Stop() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	if t.timer != nil {
+		t.timer.Stop()
+		t.timer = nil
+	}
+}
+
+// Reset stops the current timer and starts a new one with the same duration.
+func (t *Timer) Reset() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	if t.timer != nil {
+		t.timer.Stop()
+	}
+
+	t.timer = time.AfterFunc(t.duration, t.callback)
+}
+
+// SetDuration updates the timer's duration for future starts.
+func (t *Timer) SetDuration(duration time.Duration) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	t.duration = duration
+}