Ubuntu 18.04 network card configuration

ubuntu18.04 server, the new network tool netplan is enabled. Compared with 16.04 and earlier versions, the command line configuration network parameters are quite different from the previous version##

The network card configuration file is: /etc/netplan/50-cloud-init.yaml, the netplan description file uses yaml syntax, and the default is dhcp mode. If you want to configure a static address, you need to modify the content of this file.
Reference: https://netplan.io/

yaml syntax requirements:
1. Case Sensitive
2. Use indentation to indicate hierarchical relationships
3. Tab key is not allowed when indenting, only spaces are allowed.
4. The number of indented spaces is not important, as long as elements of the same level are aligned to the left
5. # Indicates a comment. From this character to the end of the line, it will be ignored by the parser.

Take Tencent Cloud Ubuntu Server 18.04.1 LTS 64-bit image as an example

1. The default configuration is DHCP mode:

• Pay attention to line indentation

root@VM-0-12-ubuntu:~# grep -v ^# /etc/netplan/50-cloud-init.yaml
network:
 version:2
 ethernets:
  eth0:
   dhcp4:true
   match:
    macaddress:52:54:00:d4:51:ad
   set-name: eth0

**2. Configure a static IP address: **

• Pay attention to line indentation

root@VM-0-12-ubuntu:~# grep -v ^# /etc/netplan/50-cloud-init.yaml
network:
 version:2
 ethernets:
  eth0:
   addresses:[10.10.0.12/24]
   gateway4:10.10.0.1
   nameservers:
     addresses:[183.60.83.19,183.60.82.98]

**3. DNS configuration: **

• Pay attention to line indentation

The DNS configuration in Ubuntu 18.04 has also been updated to systemd-resolve management. You can modify the /etc/resolv.conf configuration file to define DNS, or you can configure it directly in the /etc/netplan/50-cloud-init.yaml file, and you can use systemd- resolve --status View DNS configuration:

root@VM-0-12-ubuntu:~# systemd-resolve --status
Global
   DNSSEC NTA:10.in-addr.arpa
      16.172. in-addr.arpa
      168.192. in-addr.arpa
      17.172. in-addr.arpa
      18.172. in-addr.arpa
      19.172. in-addr.arpa
      20.172. in-addr.arpa
      21.172. in-addr.arpa
      22.172. in-addr.arpa
      23.172. in-addr.arpa
      24.172. in-addr.arpa
      25.172. in-addr.arpa
      26.172. in-addr.arpa
      27.172. in-addr.arpa
      28.172. in-addr.arpa
      29.172. in-addr.arpa
      30.172. in-addr.arpa
      31.172. in-addr.arpa
      corp
      d.f.ip6.arpa
      home
      internal
      intranet
      lan
      local
      private
      test
Link 3(eth0)
  Current Scopes: DNS
  LLMNR setting: yes
MulticastDNS setting: no
  DNSSEC setting: no
 DNSSEC supported: no
   DNS Servers:183.60.83.19183.60.82.98

4. Make the new configuration take effect

root@VM-0-12-ubuntu:~# sudo netplan apply