Ubuntu Server 上的启动时间非常长（网络配置）

Question

我一直在试图解决两个我怀疑相互关联的问题。最近，我们的网络进行了重新配置，之后，由于网络配置问题，我遇到了很长的启动时间，并且启动后，不再能够从 Win10 客户端访问 samba 文件共享。

启动时间消息：

[  OK  ] Reached target Network (Pre).
Starting Network Service...
Starting Wait for Network to be Configured...
Starting Network Name Resolution.
[  OK  ] Started Network Name Resolution.
[  OK  ] Reached target Host and Network Name Lookups.
[**    ] A start job is running for Wait for Network to be Configured (XX / no limit)

最后一条消息大约需要两分钟才能清除。我怀疑这可能是 DHCP 或 DNS 相关的问题。我还注意到 /var/log/syslog 中散布着几个“NXDOMAIN /潜在的 DVE2018-0001 违规”错误。目前，我真的不知道接下来该去哪里查找造成这种延迟的原因（或者为什么文件服务器对 Win10 客户端不可见）。顺便说一句，Samba 似乎正在运行，并且 Webmin 报告文件夹共享处于活动状态...

编辑1：

根据评论中 @heynnema 的建议，输出cat /etc/netplan/*.yaml：

# This is the network config written by 'subiquity'
network:
    ethernets:
        enp4s0:
            dhcp4: true
    version: 2

编辑2：

Samba 相关输出。

fstab 内容：

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/md2 during curtin installation
/dev/disk/by-id/md-uuid-4c695059:2f774b0b:9e5492d2:bcb62609 / ext4 defaults 0 0
/dev/disk/by-id/md-uuid-05f3f447:6002213f:2bb97c81:6416f121 none swap sw 0 0
# /boot was on /dev/md0 during curtin installation
/dev/disk/by-id/md-uuid-58dd9ab9:74b02d8a:10890b55:2212c9cb /boot ext4 defaults 0 
0
/swap.img   none    swap    sw  0   0

smb.conf 共享定义：

#======================= Share Definitions =======================

# Un-comment the following (and tweak the other settings below to suit)
# to enable the default home directory shares. This will share each
# user's home directory as \\server\username
;[homes]
;   comment = Home Directories
;   browseable = no

# By default, the home directories are exported read-only. Change the
# next parameter to 'no' if you want to be able to write to them.
;   read only = yes

# File creation mask is set to 0700 for security reasons. If you want to
# create files with group=rw permissions, set next parameter to 0775.
;   create mask = 0700

# Directory creation mask is set to 0700 for security reasons. If you want to
# create dirs. with group=rw permissions, set next parameter to 0775.
;   directory mask = 0700

# By default, \\server\username shares can be connected to by anyone
# with access to the samba server.
# Un-comment the following parameter to make sure that only "username"
# can connect to \\server\username
# This might need tweaking when using external authentication schemes
;   valid users = %S

# Un-comment the following and create the netlogon directory for Domain 
Logons
# (you need to configure Samba to act as a domain controller too.)
;[netlogon]
;   comment = Network Logon Service
;   path = /home/samba/netlogon
;   guest ok = yes
;   read only = yes

# Un-comment the following and create the profiles directory to store
# users profiles (see the "logon path" option above)
# (you need to configure Samba to act as a domain controller too.)
# The path below should be writable by all users so that their
# profile directory may be created the first time they log on
;[profiles]
;   comment = Users profiles
;   path = /home/samba/profiles
;   guest ok = no
;   browseable = no
;   create mask = 0600
;   directory mask = 0700

[printers]
   comment = All Printers
   browseable = no
   path = /var/spool/samba
   printable = yes
   guest ok = no
   read only = yes
   create mask = 0700

# Windows clients look for this share name as a source of downloadable
# printer drivers
[print$]
   comment = Printer Drivers
   path = /var/lib/samba/printers
   browseable = yes
   read only = yes
   guest ok = no
# Uncomment to allow remote administration of Windows print drivers.
# You may need to replace 'lpadmin' with the name of the group your
# admin users are members of.
# Please note that you also need to set appropriate Unix permissions
# to the drivers directory for these users to have write rights in it
;   write list = root, @lpadmin


[media_Public]
    create mode = 777
    path = /home/media/Public
    writeable = yes
    public = yes
    directory mode = 777

Answer 1

用此替换当前的/etc/netplan/*.yaml文件，并将 enpxxx 更改为第二个接口的正确名称...

    network:
      version: 2
      renderer: networkd
      ethernets:
        enp4s0:
          dhcp4: true
          optional: true
        enpxxx:
          dhcp4: true
          optional: true

sudo netplan generate

sudo netplan apply

reboot