Lab 3.2 - lxc installation fails with 'dnsmasq[]: failed to create listening socket for 10.0.3.1'

I was trying to install lxc on a Ubuntu 20.04 host but got the following failure report during installation and subsequent service invocation:
systemctl restart lxc-net.service Job for lxc-net.service failed because the control process exited with error code. See "systemctl status lxc-net.service" and "journalctl -xe" for details.
Here some more information from journalctl -xe
Aug 13 22:16:20 oldy systemd-udevd[3490]: lxcbr0: Could not generate persistent MAC: No data available Aug 13 22:16:20 oldy avahi-daemon[1018]: Joining mDNS multicast group on interface lxcbr0.IPv4 with address 10.0.3.1. Aug 13 22:16:20 oldy avahi-daemon[1018]: New relevant interface lxcbr0.IPv4 for mDNS. Aug 13 22:16:20 oldy avahi-daemon[1018]: Registering new address record for 10.0.3.1 on lxcbr0.IPv4. Aug 13 22:16:20 oldy named[1215]: listening on IPv4 interface lxcbr0, 10.0.3.1#53 Aug 13 22:16:20 oldy NetworkManager[1024]: <info> [1597346180.6219] device (lxcbr0): state change: unmanaged -> unavailable (reason 'connection-assumed', sys-iface-state: 'external') Aug 13 22:16:20 oldy lxc-net[3529]: dnsmasq: failed to create listening socket for 10.0.3.1: Address already in use Aug 13 22:16:20 oldy dnsmasq[3529]: failed to create listening socket for 10.0.3.1: Address already in use Aug 13 22:16:20 oldy dnsmasq[3529]: FAILED to start up Aug 13 22:16:20 oldy lxc-net[3487]: Failed to setup lxc-net. Aug 13 22:16:20 oldy avahi-daemon[1018]: Withdrawing address record for 10.0.3.1 on lxcbr0. Aug 13 22:16:20 oldy avahi-daemon[1018]: Leaving mDNS multicast group on interface lxcbr0.IPv4 with address 10.0.3.1. Aug 13 22:16:20 oldy NetworkManager[1024]: <info> [1597346180.6247] device (lxcbr0): state change: unavailable -> disconnected (reason 'connection-assumed', sys-iface-state: 'external') Aug 13 22:16:20 oldy avahi-daemon[1018]: Interface lxcbr0.IPv4 no longer relevant for mDNS.
So this points to:
dnsmasq: failed to create listening socket for 10.0.3.1: Address already in use
I've been trying to find this mysterious IP 10.0.3.1 but was unable - ss doesn't show it, neither does lsof -i, nor netstat.
Searching the web suggests uninstalling dnsmasq, but I have only dnsmasq-base installed. See https://stanislas.blog/2018/02/setup-network-bridge-lxc-net/
Obviously 10.0.3.1:53 is related to DNS.
Solution: Uninstall the bind9 DNS server!
I totally forgot that I had installed a bind9 DNS server which wasn't doing much.
Conclusion: lxc doesn't like DNS servers.
Comments
-
Hi @heiko_s,
Thank you for your detailed feedback. Such conflicts are to be expected on dedicated systems, where many packages have been installed over time.
One way to prevent such issues is to start with a clean system (VM) when running through a set of exercises.Regards,
-Chris1 -
Thanks Chris. That's usually what I do - using QEMU/kvm and do the labs in VMs. This time I wanted to see if lxc would be suitable to run a web server and bind9 in containers on my media PC. Following the motto: Don't just preach the word, live it.
0 -
I may include the "lesson learned" from your findings in a future course update release
2 -
^good stuff. I was going to go down the rabbit hole on this one, but a quick google led me here.
If you don't want to uninstall bind9, you can:
1. Stop the named service.- Feel free to disable it, if you think you'll reboot any time soon, so as to not repeat these steps. I just stopped it, as I rarely reboot my machines. I have 2 spare laptops and a desktop, so I just put them to sleep after I am done with them for the day.
- restart the lxc-net service
- confirm it started properly
- get on with your containers.
1 -
0
Categories
- 9.9K All Categories
- 29 LFX Mentorship
- 82 LFX Mentorship: Linux Kernel
- 473 Linux Foundation Boot Camps
- 268 Cloud Engineer Boot Camp
- 96 Advanced Cloud Engineer Boot Camp
- 44 DevOps Engineer Boot Camp
- 32 Cloud Native Developer Boot Camp
- 1 Express Training Courses
- 1 Express Courses - Discussion Forum
- 1.6K Training Courses
- 18 LFC110 Class Forum
- 4 LFC131 Class Forum
- 19 LFD102 Class Forum
- 133 LFD103 Class Forum
- 9 LFD121 Class Forum
- 60 LFD201 Class Forum
- LFD210 Class Forum
- 1 LFD213 Class Forum - Discontinued
- 128 LFD232 Class Forum
- 23 LFD254 Class Forum
- 545 LFD259 Class Forum
- 100 LFD272 Class Forum
- 1 LFD272-JP クラス フォーラム
- 1 LFS145 Class Forum
- 20 LFS200 Class Forum
- 739 LFS201 Class Forum
- 1 LFS201-JP クラス フォーラム
- 1 LFS203 Class Forum
- 37 LFS207 Class Forum
- 296 LFS211 Class Forum
- 53 LFS216 Class Forum
- 45 LFS241 Class Forum
- 40 LFS242 Class Forum
- 33 LFS243 Class Forum
- 10 LFS244 Class Forum
- 27 LFS250 Class Forum
- 1 LFS250-JP クラス フォーラム
- 131 LFS253 Class Forum
- 967 LFS258 Class Forum
- 10 LFS258-JP クラス フォーラム
- 86 LFS260 Class Forum
- 124 LFS261 Class Forum
- 29 LFS262 Class Forum
- 78 LFS263 Class Forum
- 15 LFS264 Class Forum
- 10 LFS266 Class Forum
- 17 LFS267 Class Forum
- 16 LFS268 Class Forum
- 14 LFS269 Class Forum
- 195 LFS272 Class Forum
- 1 LFS272-JP クラス フォーラム
- 207 LFW211 Class Forum
- 148 LFW212 Class Forum
- 892 Hardware
- 213 Drivers
- 74 I/O Devices
- 44 Monitors
- 115 Multimedia
- 206 Networking
- 100 Printers & Scanners
- 85 Storage
- 747 Linux Distributions
- 88 Debian
- 64 Fedora
- 13 Linux Mint
- 13 Mageia
- 24 openSUSE
- 133 Red Hat Enterprise
- 33 Slackware
- 13 SUSE Enterprise
- 354 Ubuntu
- 469 Linux System Administration
- 38 Cloud Computing
- 68 Command Line/Scripting
- Github systems admin projects
- 93 Linux Security
- 77 Network Management
- 107 System Management
- 48 Web Management
- 62 Mobile Computing
- 22 Android
- 26 Development
- 1.2K New to Linux
- 1.1K Getting Started with Linux
- 524 Off Topic
- 127 Introductions
- 210 Small Talk
- 19 Study Material
- 783 Programming and Development
- 257 Kernel Development
- 492 Software Development
- 919 Software
- 255 Applications
- 181 Command Line
- 2 Compiling/Installing
- 76 Games
- 316 Installation
- 46 All In Program
- 46 All In Forum
Upcoming Training
-
August 20, 2018
Kubernetes Administration (LFS458)
-
August 20, 2018
Linux System Administration (LFS301)
-
August 27, 2018
Open Source Virtualization (LFS462)
-
August 27, 2018
Linux Kernel Debugging and Security (LFD440)