Debian64位系统暂时还没有mongodb4.4的deb，编译安装也没试成功。
Ubuntu20.04 64位可以用这些命令装上。

wget -qO - https://www.mongodb.org/static/pgp/server-4.4.asc | sudo apt-key add -
 
echo "deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.4 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-4.4.list
 
sudo apt-get update
 
sudo apt-get install mongodb-org

装完可以启动mongod服务

systemctl start mongod
systemctl enable mongod

服务启动可能会异常，可以看下 systemctl status mongod

如报出/var/run ... 可以修改对应的服务声明 如 /lib/systemd/system/mongod.service
去掉/var

了解如何在Raspberry Pi 4上通过USB引导Ubuntu Server20.04。SD卡非常缓慢，并且容易出现数据损坏和故障。 通过升级到SSD驱动器来解决所有这些问题！

64位系统安装踩搞不少，很多apt都装不了，只能看官方有没有deb包，实在不行就需要编译安装。

可以从这里找docker的包
https://download.docker.com/linux/debian/dists/buster/pool/stable/armhf/

需要下载这三个 wget xxx

注， 64位还是beta版本，目前未发布。

2020-08-24版本

最新的可以浏览这个目录https://downloads.raspberrypi.org/raspios_arm64/images

在boot分区中写入空文件ssh即可
如 touch /Volume/boot/ssh
树每派镜像 RaspberryOS 默认密码是 raspberry

修改源/etc/apt/sources.list加速

deb http://mirrors.aliyun.com/raspbian/raspbian/ buster main non-free contrib rpi firmware
deb-src http://mirrors.aliyun.com/raspbian/raspbian/ buster main non-free contrib rpi firmware

还有 /etc/apt/sources.list.d/raspi.list

deb https://mirrors.ustc.edu.cn/archive.raspberrypi.org/debian buster main

用的阿里的：

deb https://mirrors.aliyun.com/ubuntu-ports/ focal main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu-ports/ focal main main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu-ports/ focal-updates main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu-ports/ focal-updates main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu-ports/ focal-backports main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu-ports/ focal-backports main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu-ports/ focal-security main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu-ports/ focal-security main restricted universe multiverse
# deb https://mirrors.aliyun.com/ubuntu-ports/ focal-proposed main restricted universe multiverse
# deb-src https://mirrors.aliyun.com/ubuntu-ports/ focal-proposed main restricted universe multiverse

首先说明下，本文是以树莓派作为客户端连接ss， 再用privoxy自动代理实现科学研究。
1 安装ss apt-get install shadowsocks-libev

2 禁用这个服务端服务 systemctl disable shadowsocks-libev

3 自动开启这个客户端连接服务 systemctl enable shadowsocks-libev-local@config

4 编辑ss的配置文件 vi /etc/shadowsocks-libev/config.json

事情源于在树莓派上写的定时脚本，定时获取停车费用信息。ubuntu重装后时区都用tzselect设置了，但仍在半夜收到消息通知。
于是发现需要这样设置下。

执行这个设置成中国时区 timedatectl set-timezone Asia/Shanghai

查看本地时间 timedatectl status

还有最重要的，要重启下crontab的服务. systemctl restart cron
有些系统中crontab服务为 crond。

更多关于timedatectl的帮助可以查看这个：

问题来源于raspberry pi4 安装了打印服务，但是cups服务有点异常报，/etc/securetty找不到。
查了下应该是ubuntu 20.04的bug.

root@ubuntu:~# systemctl status cups
● cups.service - CUPS Scheduler
     Loaded: loaded (/lib/systemd/system/cups.service; enabled; vendor preset: enabled)
     Active: active (running) since Wed 2020-07-01 00:58:26 CST; 12min ago
TriggeredBy: ● cups.path
             ● cups.socket
       Docs: man:cupsd(8)
   Main PID: 8324 (cupsd)
      Tasks: 2 (limit: 4434)
     CGroup: /system.slice/cups.service
             ├─8324 /usr/sbin/cupsd -l
             └─9318 /usr/lib/cups/notifier/dbus dbus://

Jul 01 01:08:15 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:15 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:22 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:22 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:27 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:27 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:29 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:29 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:39 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:39 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory

解决的办法就是新建这个文件/etc/securetty，内容为