我开始用 Digitalocean 的 ubuntu 22.04。`apt-get update` 的时候出现错误：

```bash W: https://repos.insights.digitalocean.com/apt/do-agent/dists/main/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details. ```

从这里 https://askubuntu.com/a/1403964 找到解决办法。

```bash

sudo apt-key export A4C6383F | sudo gpg –dearmour -o /usr/share/keyrings/digitalocean-agent.gpg

sudo apt-get update

sudo apt-key del A4C6383F ```

`/etc/apt/sources.list.d/digitalocean-agent.list` 修改后的样子：

```bash deb [arch=amd64 signed-by=/usr/share/keyrings/digitalocean-agent.gpg] https://repos.insights.digitalocean.com/apt/do-agent main main ```

这样就一切正常了。

更多资料：

1. https://wiki.debian.org/DebianRepository/UseThirdParty
2. https://unix.stackexchange.com/a/582853