Added first version. This script generates a complete high-availability setup by asking for your service details and then automatically creating Keepalived VRRP configuration files, Systemd service units, and a visual failover diagram for a multi-node active/passive cluster with automatic VIP failover.

keepalived-generator.sh

@@ -0,0 +1,262 @@
+#!/usr/bin/env bash
+
+echo "========================================="
+echo " Keepalived HA Full Stack Generator"
+echo " (Configs + Systemd + Diagram)"
+echo "========================================="
+echo ""
+
+read -p "Service name (e.g. DNS / API / Nginx): " SERVICE
+read -p "MASTER Router ID: " MASTER_ID
+read -p "MASTER node IP: " MASTER_IP
+echo ""
+
+read -p "How many BACKUP nodes? " BACKUP_COUNT
+
+declare -a BACKUP_IDS
+declare -a BACKUP_IPS
+
+for ((i=1; i<=BACKUP_COUNT; i++))
+do
+    echo "-----------------------------------"
+    echo "Backup #$i"
+    read -p "Router ID: " RID
+    read -p "Node IP: " IP
+
+    BACKUP_IDS[$i]=$RID
+    BACKUP_IPS[$i]=$IP
+done
+
+echo ""
+read -p "How many VIP instances? " INSTANCE_COUNT
+echo ""
+
+read -p "Use health check script? (y/n): " USE_SCRIPT
+
+if [[ "$USE_SCRIPT" == "y" ]]; then
+    read -p "Health check script path: " HEALTH_SCRIPT
+else
+    HEALTH_SCRIPT=""
+fi
+
+MASTER_CONF="keepalived-${SERVICE}-${MASTER_ID}.conf"
+BACKUP_PREFIX="keepalived-${SERVICE}-backup"
+
+SYSTEMD_DIR="systemd-${SERVICE}"
+DIAGRAM_FILE="${SERVICE}-ha-diagram.md"
+
+mkdir -p "$SYSTEMD_DIR"
+
+# ---------------- SYSTEMD ----------------
+
+cat > "$SYSTEMD_DIR/keepalived.service" <<EOF
+[Unit]
+Description=Keepalived High Availability Service ($SERVICE)
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=forking
+ExecStart=/usr/sbin/keepalived --dont-fork
+ExecReload=/bin/kill -HUP \$MAINPID
+Restart=always
+RestartSec=3
+
+[Install]
+WantedBy=multi-user.target
+EOF
+
+# ---------------- DIAGRAM HEADER ----------------
+
+cat > "$DIAGRAM_FILE" <<EOF
+# $SERVICE High Availability Diagram
+
+\`\`\`mermaid
+flowchart LR
+
+VIP[(Virtual IPs)]
+
+MASTER[$MASTER_ID\\n$MASTER_IP]
+
+VIP --> MASTER
+EOF
+
+for ((b=1; b<=BACKUP_COUNT; b++))
+do
+cat >> "$DIAGRAM_FILE" <<EOF
+B$b[${BACKUP_IDS[$b]}\\n${BACKUP_IPS[$b]}]
+VIP -. failover .-> B$b
+EOF
+done
+
+cat >> "$DIAGRAM_FILE" <<EOF
+
+style MASTER fill:#4caf50,stroke:#000,color:#fff
+style VIP fill:#2196f3,stroke:#000,color:#fff
+\`\`\`
+EOF
+
+# ---------------- CONFIG FILES ----------------
+
+write_global() {
+cat <<EOF
+global_defs {
+    router_id $1
+    enable_script_security
+    script_user root
+}
+EOF
+}
+
+write_script() {
+if [[ -n "$HEALTH_SCRIPT" ]]; then
+cat <<EOF
+
+vrrp_script chk_service {
+    script "$HEALTH_SCRIPT"
+    interval 2
+    timeout 2
+    rise 2
+    fall 2
+    weight -50
+}
+EOF
+fi
+}
+
+# MASTER base
+write_global "$MASTER_ID" > "$MASTER_CONF"
+write_script >> "$MASTER_CONF"
+
+# BACKUP base files
+for ((b=1; b<=BACKUP_COUNT; b++))
+do
+    write_global "${BACKUP_IDS[$b]}" > "$BACKUP_PREFIX$b.conf"
+    write_script >> "$BACKUP_PREFIX$b.conf"
+done
+
+# ---------------- INSTANCES ----------------
+
+for ((i=1; i<=INSTANCE_COUNT; i++))
+do
+    echo "-----------------------------------"
+    echo "Instance #$i"
+    read -p "Name (e.g. VLAN10 / APP1): " NAME
+    read -p "Interface (e.g. eth0.10): " IFACE
+    read -p "VIP (e.g. 192.168.10.3/24): " VIP
+    read -p "VRID: " VRID
+    read -p "Auth password: " PASS
+
+    PEERS=""
+    for ((b=1; b<=BACKUP_COUNT; b++))
+    do
+        PEERS="$PEERS ${BACKUP_IPS[$b]}"
+    done
+
+    # MASTER
+    cat >> "$MASTER_CONF" <<EOF
+
+vrrp_instance $NAME {
+    state MASTER
+    interface $IFACE
+    virtual_router_id $VRID
+    priority 200
+    advert_int 1
+
+    unicast_src_ip $MASTER_IP
+
+    unicast_peer {
+        $PEERS
+    }
+
+    authentication {
+        auth_type PASS
+        auth_pass $PASS
+    }
+
+    virtual_ipaddress {
+        $VIP dev $IFACE
+    }
+EOF
+
+if [[ -n "$HEALTH_SCRIPT" ]]; then
+cat >> "$MASTER_CONF" <<EOF
+
+    track_script {
+        chk_service
+    }
+EOF
+fi
+
+cat >> "$MASTER_CONF" <<EOF
+}
+EOF
+
+    # BACKUPS
+    for ((b=1; b<=BACKUP_COUNT; b++))
+do
+    PRIORITY=$((200 - (b * 10)))
+    [[ $PRIORITY -lt 50 ]] && PRIORITY=50
+
+    cat >> "$BACKUP_PREFIX$b.conf" <<EOF
+
+vrrp_instance $NAME {
+    state BACKUP
+    interface $IFACE
+    virtual_router_id $VRID
+    priority $PRIORITY
+    advert_int 1
+    nopreempt
+
+    unicast_src_ip ${BACKUP_IPS[$b]}
+
+    unicast_peer {
+        $MASTER_IP
+    }
+
+    authentication {
+        auth_type PASS
+        auth_pass $PASS
+    }
+
+    virtual_ipaddress {
+        $VIP dev $IFACE
+    }
+EOF
+
+if [[ -n "$HEALTH_SCRIPT" ]]; then
+cat >> "$BACKUP_PREFIX$b.conf" <<EOF
+
+    track_script {
+        chk_service
+    }
+EOF
+fi
+
+cat >> "$BACKUP_PREFIX$b.conf" <<EOF
+}
+EOF
+
+done
+
+done
+
+echo ""
+echo "========================================="
+echo " DONE"
+echo "========================================="
+echo "Configs:"
+echo " - $MASTER_CONF"
+for ((b=1; b<=BACKUP_COUNT; b++))
+do
+    echo " - $BACKUP_PREFIX$b.conf"
+done
+
+echo ""
+echo "Systemd:"
+echo " - $SYSTEMD_DIR/keepalived.service"
+
+echo ""
+echo "Diagram:"
+echo " - $DIAGRAM_FILE"
+echo "========================================="