：RDS Custom網路簡介

手動建立指令碼並設定開機自啟動

1. 在/etc目錄下建立rds_custom_init.sh指令碼，指令碼的具體內容如下。

   rds_custom_init.sh指令碼

   #!/bin/bash
   echo "RDS CUSTOM INIT START, $(date)" >> /tmp/rds_custom_init.log
   flag=0
   for ((i=1; i<=5; i++)); do
       eth1_ip=$(ip address show eth1 | grep "inet " | awk "{print \$2}" | cut -d'/' -f1)  
       if [[ -n "$eth1_ip" ]]; then
           break
       else
           sleep 1
       fi
   done
   eth0_gateway=$(ip route | grep "default via " | grep "eth0" | awk "{print \$3}")
   # check eth0_gateway
   if [ -z "$eth0_gateway" ]; then
       if [ -f /etc/eth0_gateway ]; then
           eth0_gateway=$(cat /etc/eth0_gateway)
       else
           echo "No gateway found for eth0, and /etc/eth0_gateway file does not exist." >> /tmp/rds_custom_init.log
           exit 0
       fi
   fi
   if [ -z "$eth1_ip" ] && ip address show | grep -q "eth1"; then
       if lsb_release -a 2>/dev/null | grep -q -e "Ubuntu 16.04" -e "Debian"; then
         sed -i 's/eth0/eth1/g' /etc/network/interfaces
         echo "auto eth0" >> /etc/network/interfaces
         echo "iface eth0 inet dhcp" >> /etc/network/interfaces
         sudo systemctl restart networking
         flag=1
         echo "UP ETH1 FOR UBUNTU 16.04 or Debian, $(date)" >> /tmp/rds_custom_init.log
       else   
         HWADDR=$(ip address show eth1 | grep "link/ether" | awk "{print \$2}")
         echo -e "DEVICE=eth1\nBOOTPROTO=dhcp\nONBOOT=yes\nTYPE=Ethernet\nUSERCTL=yes\nPEERDNS=no\nIPV6INIT=no\nPERSISTENT_DHCLIENT=yes\nHWADDR=$HWADDR\nDEFROUTE=yes" | tee /etc/sysconfig/network-scripts/ifcfg-eth1 > /dev/null
         service network restart
         echo "UP ETH1, $(date)" >> /tmp/rds_custom_init.log
       fi
   fi
   eth1_ip=$(ip address show eth1 | grep "inet " | awk "{print \$2}" | cut -d'/' -f1)
   if [ "$flag" -eq 0 ] && lsb_release -a 2>/dev/null | grep -q "Ubuntu 16.04"; then
     sudo systemctl restart networking
     echo "UP ETH1 FOR UBUNTU 16.04, $(date)" >> /tmp/rds_custom_init.log
   fi
   if [ -n "$eth1_ip" ]; then
       ip route add 100.100.0.0/16 via $eth0_gateway dev eth0 2> /dev/null
       keep_route="100.100.0.0/16 via $eth0_gateway dev eth0"
       routes=$(ip route | grep "dev eth0")
       echo "$routes" | while read -r route; do
         if [[ "$route" != "$keep_route" ]]; then
           prefix=$(echo "$route" | awk "{print \$1}")
           ip route delete $prefix dev eth0 > /dev/null
         fi
       done
       echo "DELETE IP ROUTE FOR ETH0, $(date)" >> /tmp/rds_custom_init.log
       eth1_gateway=$(ip route | grep "default via " | grep "eth1" | awk "{print \$3}")
       if ip route | grep -q "100.100.2.136 via $eth1_gateway dev eth1"; then
         ip route delete 100.100.2.136 via "$eth1_gateway" dev eth1
       fi
       if ip route | grep -q "100.100.2.138 via $eth1_gateway dev eth1"; then
         ip route delete 100.100.2.138 via "$eth1_gateway" dev eth1
       fi
       ip route add 100.100.2.136 via $eth1_gateway dev eth1 2> /dev/null
       ip route add 100.100.2.138 via $eth1_gateway dev eth1 2> /dev/null
       ip route delete default via $eth1_gateway dev eth1 2> /dev/null
       ip route add default via $eth1_gateway dev eth1 metric 0 2> /dev/null
   fi
   echo "RDS CUSTOM INIT FINISHED, $(date)" >> /tmp/rds_custom_init.log

2. 執行chmod a+x /etc/rds_custom_init.sh為該指令碼授予可執行許可權。

3. 編輯/etc/rc.local，將rds_custom_init.sh指令碼配置為開機自啟動。

   • 若系統非Ubuntu，請在/etc/rc.local中增加/etc/rds_custom_init.sh，並為/etc/rc.local授予相應許可權。

     chmod 777 /etc/rc.local

   • 若系統為Ubuntu，請配置並開啟rc-local.service服務。

     1. 編輯/lib/systemd/system/rc-local.service，增加如下內容。

        [Install]
        WantedBy=multi-user.target

     2. 將rc-local.service服務配置為開機自啟動。

        #設定為開機自啟動服務
        systemctl enable rc-local.service
        #檢查開機自啟動服務
        systemctl is-enabled rc-local.service

     3. 啟動rc-local.service服務。

        #啟動服務 
        systemctl start rc-local.service
        #檢查服務
        systemctl status rc-local.service

     說明

     Ubuntu20.04、22.04和24.04預設支援自動設定綁定的輔助彈性網卡。如自動設定未能成功，請執行以下手動設定步驟。

     手動設定步驟

     1. 執行以下命令，開啟輔助彈性網卡的設定檔。

        vi /etc/netplan/eth1-netcfg.yaml

     2. 在網卡設定檔中添加以下輔助彈性網卡的資訊，然後儲存並退出。

        network:
          version: 2
          renderer: networkd
          ethernets:
            eth1:
              dhcp4: yes
              dhcp6: no

     3. 執行以下命令以使配置生效。

        netplan apply