使用ifupdown时DNS中断，升级到Ubuntu22.04后系统解析

Question

TL;DR

sudo cp -p /etc/network/if-up.d/resolved /etc/network/if-up.d/.resolved.broken-orig

#Edit /etc/network/if-up.d/resolved and take out the extraneous quotes on lines 48 and 52
#The fix looks like:
diff /etc/network/if-up.d/.resolved.broken-orig /etc/network/if-up.d/resolved
48c48
< "$DNS"="$NEW_DNS"
---
> $DNS="$NEW_DNS"
52c52
< "$DOMAINS"="$NEW_DOMAINS"
---
> $DOMAINS="$NEW_DOMAINS"

至少，这似乎是有效的。

最近，通过do-release-upgrade将一个旧系统升级到Ubuntu22.04.1LTS，并遇到DNS问题，错误消息如下：

nslookup google.com
Server:     127.0.0.53
Address:    127.0.0.53#53

** server can't find google.com: SERVFAIL

和

/etc/network/if-down.d/resolved: 12: mystatedir: not found
/etc/network/if-up.d/resolved: 71: DNS: not found
/etc/network/if-up.d/resolved: 1: /run/network/ifupdown-inet-em1: DNS=8.8.8.8: not found
/etc/network/if-up.d/resolved: 2: /run/network/ifupdown-inet-em1: DOMAINS=local_search_domain.com: not found
Failed to parse DNS server address: DNS
Failed to set DNS configuration: Invalid argument

当试图通过/etc/ nslookup /接口中定义的网络连接(em1)运行系统升级之前。

经过一段时间的自我安慰后，我找到了https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1981103和https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1910273，这有助于增强我的平静。看起来，所遇到的错误至少是由于在/etc/ network /if-up.d/解题中输入了一对字体，这些输入很容易被文本编辑器修复；在手动删除多余的引号之后，我能够打开网络接口并查询DNS服务器。我不清楚Ubuntu22.04.1LTS (0.8.36+nmu1ubuntu3)目前提供的0.8.36+nmu1ubuntu3包是否还有其他问题，或者上面描述的手动编辑。是否有任何文档化的修补程序不涉及编辑/etc/network/if-up.d/ upgraded的第48和52行，或者这是当前升级到Ubuntu22.04.1 LTS的遗留系统的最佳解决方案？

Answer 1

我撞到了我的Ubuntu服务器18.04->22.04，遇到了这个问题。正如你说得很清楚(谢谢！)更新/etc/network/if-up.d/resolved并以这样的方式删除2个引用的变量：

sudo vim /etc/network/if-up.d/.resolved.broken-orig

Old: "$DNS"="$NEW_DNS"
-->
New: $DNS="$NEW_DNS"

Old: "$DOMAINS"="$NEW_DOMAINS"
-->
New: $DOMAINS="$NEW_DOMAINS"

在重新启动后解决此问题。