Debian /etc/network/interfaces 未在啟動時載入（如何修復競爭條件）

我有一個以前可以工作的伺服器配置，但最近我做了一個更新，它似乎壞了一些東西。我相信最初有兩個問題，我已經解決了第一個問題。當我瀏覽時，我注意到systemctl status networking一個我以前從未見過的命令失敗了。我查了一下，是從一個我以前從未見過的包裹裡拿出來的，ifupdown2。我安裝了它並解決了該錯誤。我認為這是添加的未標記依賴項，因為我以前從未需要該包。

現在，當我的伺服器啟動時，networking服務執行成功，但沒有設置任何網路配置：

# ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1
   link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp2s5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
   link/ether 00:1e:2a:c2:08:13 brd ff:ff:ff:ff:ff:ff
# 
# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
   link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
   inet 127.0.0.1/8 scope host lo
      valid_lft forever preferred_lft forever
   inet6 ::1/128 scope host 
      valid_lft forever preferred_lft forever
2: enp2s5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
   link/ether 00:1e:2a:c2:08:13 brd ff:ff:ff:ff:ff:ff
   inet6 fe80::21e:2aff:fec2:813/64 scope link 
      valid_lft forever preferred_lft forever
# 
# ip route # This is not a copy-paste error, it actually just prints nothing
# 
# journalctl -u networking
-- Logs begin at Thu 2019-03-28 15:17:47 CDT, end at Thu 2019-03-28 15:19:18 CDT. --
Mar 28 15:17:51 linux-01 systemd[1]: Starting ifupdown2 networking initialization...
Mar 28 15:17:51 linux-01 networking[572]: networking: Configuring network interfaces
Mar 28 15:17:54 linux-01 systemd[1]: Started ifupdown2 networking initialization.

這是我的 /etc/network/interfaces 文件：

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug enp2s5
iface enp2s5 inet static
       address 10.0.6.164/24
       gateway 10.0.6.1
       # dns-* options are implemented by the resolvconf package, if installed
       dns-nameservers 8.8.8.8

networking如果我重新載入它一切正常，即使成功啟動了奇怪的部分。

# ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1
   link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp2s5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
   link/ether 00:1e:2a:c2:08:13 brd ff:ff:ff:ff:ff:ff
#
# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
   link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
   inet 127.0.0.1/8 scope host lo
      valid_lft forever preferred_lft forever
   inet6 ::1/128 scope host 
      valid_lft forever preferred_lft forever
2: enp2s5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
   link/ether 00:1e:2a:c2:08:13 brd ff:ff:ff:ff:ff:ff
   inet 10.0.6.164/24 scope global enp2s5
      valid_lft forever preferred_lft forever
   inet6 fe80::21e:2aff:fec2:813/64 scope link 
      valid_lft forever preferred_lft forever
#
# ip route
default via 10.0.6.1 dev enp2s5 
10.0.6.0/24 dev enp2s5 proto kernel scope link src 10.0.6.164

我認為這可能是基於此的競爭條件。我從 journalctl 中擷取了 3 個失敗，它們都包含如下內容：

Mar 28 15:11:51 linux-01 kernel: r8169 0000:02:05.0 enp2s5: link down
Mar 28 15:11:51 linux-01 kernel: r8169 0000:02:05.0 enp2s5: link down
Mar 28 15:11:51 linux-01 kernel: IPv6: ADDRCONF(NETDEV_UP): enp2s5: link is not ready
Mar 28 15:11:51 linux-01 systemd[1]: Started ifupdown2 networking initialization.
Mar 28 15:11:51 linux-01 systemd[1]: Reached target Network.
Mar 28 15:11:51 linux-01 systemd[1]: Starting Permit User Sessions...
Mar 28 15:11:51 linux-01 systemd[1]: Starting Fail2Ban Service...
...
Mar 28 15:11:54 linux-01 kernel: r8169 0000:02:05.0 enp2s5: link up
Mar 28 15:11:54 linux-01 kernel: IPv6: ADDRCONF(NETDEV_CHANGE): enp2s5: link becomes ready

似乎系統正在嘗試在設備準備好之前載入網路配置，但我不知道如何讓它等到它準備好。另外，不應該allow-hotplug enp2s5使時間無關緊要嗎？

誰能確認我對問題的評估，誰能告訴我如何讓 systemd 等到設備準備好？

注意：我不再對伺服器進行物理訪問，獲得它是一個巨大的痛苦。在我 100% 確定它會起作用之前，我寧願不進行任何重啟。

感謝@Mark Wagner 的建議：

我猜想將 auto enp2s5 添加到 /etc/network/interfaces 會解決這個問題。

我不確定 auto 和 allow-hotplug 之間的區別是什麼，但這似乎已經解決了問題。

引用自：https://serverfault.com/questions/960653