【常用操作】ubuntu部署说明

一、配置远程桌面连接

1、配置网络

• 修改网络配置信息

root@node253:~# cat /etc/netplan/01-network-manager-all.yaml 
# Let NetworkManager manage all devices on this system
network:
  version: 2
  renderer: NetworkManager
  ethernets: 
    ens160: 
      dhcp4: false
      addresses: [172.16.21.243/24]
    ens192: 
      dhcp4: false
      addresses: [66.66.67.253/24]
      gateway4: 66.66.66.1
      nameservers: 
        addresses: [114.114.114.114,8.8.8.8]
root@node253:~# netplan --debug apply

2、配置ssh登录

• 安装openssh-server，开放22端口

sudo apt-get install openssh-server
sudo ufw allow 22

• 配置允许root用户远程登录，重启ssh服务

root@node253:~# cat /etc/ssh/sshd_config
LoginGraceTime 2m
PermitRootLogin yes
StrictModes yes
root@node253:~# systemctl restart sshd

• Q&A
  • 使用xftp上传文件失败，提示服务器发送了一个意外的数据包。received:3,expected:20
    查看相关资料为新版sshd与xshell存在兼容性问题，需要追加配置信息如下，重启sshd服务即可

root@node253:~# echo "KexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group14-sha1" >> /etc/ssh/sshd_config
root@node253:~# systemctl restart sshd

3、配置远程桌面

注：GUI界面下执行快捷键Ctl + Alt + T可调出命令行窗口

3.1、设置桌面分辨率

安装ubuntu系统之后，默认只有1024 x 768和800 x 600两种分辨率

• 增加分辨率选项配置
  添加1920x1080及1366x768分辨率配置如下：

xrandr --newmode $(cvt 1920 1080 60 | grep Mode | sed -e 's/.*"/1920x1080/')
xrandr --addmode VGA-1 1920x1080

xrandr --newmode $(cvt 1366 768 60 | grep Mode | sed -e 's/.*"/1366x768/')
xrandr --addmode VGA-1 1366x768

• 选择设置-显示器，设置对应分辨率选项，应用配置即可

Q&A

1、xrandr:failed to get size of gamma for output default

• 问题描述：
  在使用xrandr进行分辨率设置的时候，出现错误“xrandr:failed to get size of gamma for output default”，尝试多种方法无解，使用以下方法方可解决，但暂不清楚具体什么原因，此处只做记录，后续再研究下
• 解决方法：
  添加以下配置文件信息，重启即可

root@node254:~# cat /etc/xorg.conf 
Section "Monitor"
        Identifier   "Monitor0"
        VendorName   "Monitor Vendor"
        ModelName    "Monitor Model"
        HorizSync   28.0 - 70.0
        VertRefresh     56.0 - 75.0
EndSection


Section "Device"
        Identifier  "VMware SVGA"
        Driver      "vesa"
EndSection


Section "Screen"
        Identifier "Screen0"
        Device     "Card0"
        Monitor    "Monitor0"
        SubSection "Display"
                Viewport   0 0
                Depth     24
                Modes     "1920x1080_60.00"
        EndSubSection
EndSection

3.2、配置远程桌面

3.2.1、开启屏幕共享

选择设置-共享，点击屏幕共享选项，打开设置开关，勾选需要密码，选择对应网卡

3.2.2、安装xrdp

sudo apt-get install xrdp -y

3.2.3、安装dconf-editor及配置

此步骤主要用于关闭远程连接加密请求，否则会出现“vnc连接提示不支持安全类型”错误

• 安装dcof-editor

sudo apt-get install dconf-editor

• 配置remote-access
  启动dconf编辑器，选择org->gnome->desktop->remote-access，关闭"requlre-encryption"开关

3.2.3、windows远程访问

此时，使用windows的mstsc远程桌面访问即可，选择vnc-any会话，输入ip和密码即可访问ubuntu远程桌面

二、更换系统内核版本

Ubuntu 20.04.2 LTS系统默认内核版本为5.4.0-42-generic

1、查看当前指定版本可用软件包

root@node254:~# apt-cache search 5.4.0-42-generic
linux-buildinfo-5.4.0-42-generic - Linux kernel buildinfo for version 5.4.0 on 64 bit x86 SMP
linux-cloud-tools-5.4.0-42-generic - Linux kernel version specific cloud tools for version 5.4.0-42
linux-headers-5.4.0-42-generic - Linux kernel headers for version 5.4.0 on 64 bit x86 SMP
linux-image-5.4.0-42-generic - Signed kernel image generic
linux-image-unsigned-5.4.0-42-generic - Linux kernel image for version 5.4.0 on 64 bit x86 SMP
linux-modules-5.4.0-42-generic - Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
linux-modules-extra-5.4.0-42-generic - Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
linux-tools-5.4.0-42-generic - Linux kernel version specific tools for version 5.4.0-42
linux-modules-nvidia-390-5.4.0-42-generic - Linux kernel nvidia modules for version 5.4.0-42
linux-modules-nvidia-418-server-5.4.0-42-generic - Linux kernel nvidia modules for version 5.4.0-42
linux-modules-nvidia-435-5.4.0-42-generic - Linux kernel nvidia modules for version 5.4.0-42
linux-modules-nvidia-440-5.4.0-42-generic - Linux kernel nvidia modules for version 5.4.0-42
linux-modules-nvidia-440-server-5.4.0-42-generic - Linux kernel nvidia modules for version 5.4.0-42

2、下载指定版本linux-images和linux-headers

root@node254:~# apt-get install linux-image-5.4.0-42-generic linux-headers-5.4.0-42-generic -y

3、设置系统默认启动内核版本

• 查看当前系统启动项

root@node254:~# grep menuentry /boot/grub/grub.cfg
if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
  menuentry_id_option=""
export menuentry_id_option
menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-98224eb1-df53-4a47-bc17-d2a84efd4225' {
submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-98224eb1-df53-4a47-bc17-d2a84efd4225' {
    menuentry 'Ubuntu，Linux 5.8.0-53-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.8.0-53-generic-advanced-98224eb1-df53-4a47-bc17-d2a84efd4225' {
    menuentry 'Ubuntu, with Linux 5.8.0-53-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.8.0-53-generic-recovery-98224eb1-df53-4a47-bc17-d2a84efd4225' {
    menuentry 'Ubuntu，Linux 5.8.0-43-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.8.0-43-generic-advanced-98224eb1-df53-4a47-bc17-d2a84efd4225' {
    menuentry 'Ubuntu, with Linux 5.8.0-43-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.8.0-43-generic-recovery-98224eb1-df53-4a47-bc17-d2a84efd4225' {
    menuentry 'Ubuntu，Linux 5.4.0-42-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.4.0-42-generic-advanced-98224eb1-df53-4a47-bc17-d2a84efd4225' {
    menuentry 'Ubuntu, with Linux 5.4.0-42-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.4.0-42-generic-recovery-98224eb1-df53-4a47-bc17-d2a84efd4225' {
menuentry 'Memory test (memtest86+)' {
menuentry 'Memory test (memtest86+, serial console 115200)' {

如上所示，启动过程中GRUB菜单如下，GRUB_DEFAULT默认为0，即默认使用ubuntu选项启动系统
选项索引从0开始，当需要选择子菜单选项时，则表示为一级菜单索引号> 二级菜单索引号；示例需要选择Ubuntu，Linux 5.4.0-42-generic选项启动，则GRUB_DEFAULT为1> 4
注：>后需加空格隔开

• Ubuntu
• Advanced options for Ubuntu
  • Ubuntu，Linux 5.8.0-53-generic
  • Ubuntu, with Linux 5.8.0-53-generic (recovery mode)
  • Ubuntu，Linux 5.8.0-43-generic
  • Ubuntu, with Linux 5.8.0-43-generic (recovery mode)
  • Ubuntu，Linux 5.4.0-42-generic
  • Ubuntu, with Linux 5.4.0-42-generic (recovery mode)
• Memory test (memtest86+)
• Memory test (memtest86+, serial console 115200)

注：系统引导页面示意如下：

• 修改启动选项，更新grub信息，重启系统即可

root@node254:~# cat /etc/default/grub | grep "GRUB_DEFAULT"
GRUB_DEFAULT="1> 4"
root@node254:~# update-grub
root@node254:~# reboot