目錄表

Ubuntu 18/20 相關設定整理

Ubuntu 18/20 相關設定整理

網路 IP 設定

參考

Exp. 更改 IP 設定為 192.168.11.204

sudo vi /etc/netplan/00-installer-config.yaml

network:
  ethernets:
    ens18:
      addresses: [192.168.11.204/24]
      gateway4: 192.168.11.1
      nameservers:
        addresses: [8.8.8.8,8.8.4.4]
      dhcp4: no
  version: 2

Exp. 兩張網卡指定 default route 為 eth0

sudo vi /etc/netplan/00-installer-config.yaml

network:
  ethernets:
    eth0:
      dhcp4: true
    eth1:
      addresses: [192.168.7.101/24]
      routes:
        - to: 192.168.7.0/24
          via: 192.168.7.1
          metric: 40
          table: 200
      nameservers:
         addresses: [8.8.8.8,168.95.192.1]
      dhcp4: no
  version: 2

localadmin@iiidevops-1:~$ ip route
default via 172.17.13.177 dev eth0 proto dhcp src 172.17.13.189 metric 100
172.17.13.176/28 dev eth0 proto kernel scope link src 172.17.13.189
172.17.13.177 dev eth0 proto dhcp scope link src 172.17.13.189 metric 100
192.168.7.0/24 dev eth1 proto kernel scope link src 192.168.7.101

可以透過 sudo netplan apply 立即生效或是 sudo reboot 重新開機後生效

修改 iptables 規則, 重開機仍能自動生效

參考 - https://askubuntu.com/questions/1452706/problem-with-my-iptables-configuration-on-reboot/1452833#1452833
需要安裝 iptables-persistent 套件
```
apt install iptables-persistent -y
```

修改 iptables 規則 Exp.

iptables -I FORWARD -i br0 -p all -j ACCEPT

將修改後的規則寫入 /etc/iptables/rules.v4
```
iptables-save -c > /etc/iptables/rules.v4
```

更改 hostname (一)

參考 - https://www.itread01.com/content/1541622152.html

先 /etc/cloud/cloud.cfg 內 preserve_hostname 為 true

sudo vi /etc/cloud/cloud.cfg

:
preserve_hostname: true
:

執行 hostnamectl 設定 hostname Exp. 更改為 pve-devops1
```
sudo hostnamectl set-hostname pve-devops1
```

更改 hostname (二)

Exp. 設定 hostname 為 iServStorM1

sudo su -
vi /etc/hosts

127.0.0.1       localhost
127.0.1.1       iServStorM1
:

vi /etc/hostname

iServStorM1

hostname -F /etc/hostname

參考網址 -
- http://computer.jges.mlc.edu.tw/index.php/ubuntu/112-ubuntu-14-04-%E8%A8%AD%E5%AE%9Ahostname

建立使用者命令

參考 - https://www.cyberciti.biz/faq/create-a-user-account-on-ubuntu-linux/

Exp. 建立 localadmin

sudo useradd -s /bin/bash -d /home/localadmin/ -m -G sudo localadmin
sudo passwd localadmin

如果useradd 建立時沒提供 sudo 權限可以之後透過 usermod 來處理 Exp.
```
sudo usermod -aG sudo localadmin
```

查詢安裝套件檔案路徑

參考網址 - https://www.ubuntu-tw.org/modules/newbb/viewtopic.php?post_id=81494

語法 : dpkg -L 套件名稱 Exp. docker

/# dpkg -L docker
/.
/usr
/usr/share
/usr/share/doc
/usr/share/doc/docker
/usr/share/doc/docker/changelog.Debian.gz
/usr/share/doc/docker/copyright

Server 版安裝圖形操作介面

sudo apt-get install --no-install-recommends ubuntu-desktop

參考網址 -
- http://www.arthurtoday.com/2012/11/ubuntu-server-install-unity-gui.html

清除系統檔案空間

System Journal Logs Ref - https://ubuntuhandbook.org/index.php/2020/12/clear-systemd-journal-logs-ubuntu/

查看目前已使用空間

root@demo-77:/var/log/journal/4ad9885bb19142118fd758b3be95057e# journalctl --disk-usage
Archived and active journals take up 4.0G in the file system.

即時清除保留兩天

root@demo-77:/var/log/journal/4ad9885bb19142118fd758b3be95057e# journalctl --rotate
root@demo-77:/var/log/journal/4ad9885bb19142118fd758b3be95057e# journalctl --vacuum-time=2days
:
root@demo-77:/var/log/journal/4ad9885bb19142118fd758b3be95057e# journalctl --disk-usage
Archived and active journals take up 16.0M in the file system.

設定最多使用空間 Exp. 500M

vi /etc/systemd/journald.conf

:
[Journal]
:
SystemMaxUse=500M
:

systemctl daemon-reload

VMWare 內出現的 multipathd 異常訊息

參考 - https://askubuntu.com/questions/1242731/ubuntu-20-04-multipath-configuration

在 VMWare 內建立 Ubuntu 20.04 的 VM , 在 /var/log/syslog 會看到以下的異常訊息

~# tail -f /var/log/syslog
Aug 31 10:43:07 iiidevops4 multipathd[747]: sda: add missing path
Aug 31 10:43:09 iiidevops4 multipathd[747]: sda: failed to get udev uid: Invalid argument
Aug 31 10:43:11 iiidevops4 multipathd[747]: sda: failed to get sysfs uid: Invalid argument
Aug 31 10:43:12 iiidevops4 multipathd[747]: sda: failed to get sgio uid: No such file or directory
Aug 31 10:43:17 iiidevops4 multipathd[747]: sda: add missing path

解決方式 :

vi /etc/multipath.conf

defaults {
    user_friendly_names yes
}
blacklist {
    devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st|sda)[0-9]*"
}

systemctl restart multipath-tools

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