1、window端ssh连接不上
在/etc/ssh/sshd_config文件中添加
KexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1
2、apt-get update报错Some index files failed to download. They have been ignored, or old ones used instead
首先修改 /etc/systemd/resolved.conf 文件，在其中添加dns信息
DNS=8.8.8.8 8.8.4.4
保存退出。
然后以root执行如下命令：
systemctl restart systemd-resolved
systemctl enable systemd-resolved
mv /etc/resolv.conf /etc/resolv.conf.bak
ln -s /run/systemd/resolve/resolv.conf /etc/
重启OK。
3、安装python2和python3以及对应pip
sudo apt install wget python-is-python2 # 安装wget和python2
wget https://bootstrap.pypa.io/pip/2.7/get-pip.py
python get-pip.py
sudo apt install wget python python3 python3-pip python-ply python3-ply -y
wget https://bootstrap.pypa.io/pip/2.7/get-pip.py
python get-pip.py
4、开机慢，卡在
ubuntu 20.04 a start job is running for wait for network to be configuared
解决：
cd /etc/systemd/system/network-online.target.wants/
sudo vim systemd-networkd-wait-online.service
在[Service]下增加
TimeoutStartSec=2sec
