Public bug reported: A server I have stopped being able to resolve DNS queries. According to resolvectl status, no DNS servers have been configured.
/etc/netplan/01-netcfg.yaml has networking configuration that looks correct to me, and if I do 'netplan try', I get working a network. Somehow systemd's configuration diverged from netplan's. Before I did the 'netplan try', I looked at /run/systemd/network/. There was one file in it, /run/systemd/network/, with just [Match] [Link] WakeOnLan=magic in it. The timestamp on that file is Apr 7, 06:28, which is almost 24 hours since the last reboot. journalctl shows this at around that timestamp: Apr 07 06:27:56 momsen systemd[1]: Starting Daily apt upgrade and clean activities... Apr 07 06:27:56 momsen postfix/smtpd[38430]: disconnect from unknown[121.66.35.37] ehlo=1 auth=0/1 quit=1 commands=2/3 Apr 07 06:28:01 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:01 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:01 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:01 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:01 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:01 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:01 momsen systemd[1]: Reloading. Apr 07 06:28:01 momsen kernel: traps: netplan[38842] general protection fault ip:55c8cfed3cf0 sp:7fff25300030 error:0 in generate[55c8cfed0000+8000] Apr 07 06:28:01 momsen systemd[38840]: /usr/lib/systemd/system-generators/netplan terminated by signal SEGV. Apr 07 06:28:01 momsen systemd[1]: /lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly. Apr 07 06:28:01 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:01 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen dbus-daemon[548]: [system] Reloaded configuration Apr 07 06:28:02 momsen systemd[1]: Reexecuting. Apr 07 06:28:02 momsen systemd[1]: systemd 245.4-4ubuntu3.6 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN +PCRE2 default-hierarchy=hybrid) Apr 07 06:28:02 momsen systemd[1]: Detected architecture x86-64. Apr 07 06:28:02 momsen kernel: traps: netplan[39030] general protection fault ip:563995b5acf0 sp:7ffc8299c2f0 error:0 in generate[563995b57000+8000] Apr 07 06:28:02 momsen systemd[39028]: /usr/lib/systemd/system-generators/netplan terminated by signal SEGV. ... Apr 07 06:28:03 momsen kernel: traps: netplan[39132] general protection fault ip:55f15ae8ecf0 sp:7fff9cbcb100 error:0 in generate[55f15ae8b000+8000] Apr 07 06:28:03 momsen systemd[39130]: /usr/lib/systemd/system-generators/netplan terminated by signal SEGV. ... Apr 07 06:28:07 momsen systemd-udevd[429]: /run/systemd/network/10-netplan-enp35s0.link: No valid settings found in the [Match] section, ignoring file. To match all interfaces, add OriginalName=* in the [Match] section. Apr 07 06:28:08 momsen systemd[1]: Reloading. Apr 07 06:28:08 momsen kernel: traps: netplan[40203] general protection fault ip:55bbc1fe6cf0 sp:7ffedcbfea00 error:0 in generate[55bbc1fe3000+8000] Apr 07 06:28:08 momsen systemd[40201]: /usr/lib/systemd/system-generators/netplan terminated by signal SEGV. ... Apr 07 06:28:22 momsen systemd[1]: apt-daily-upgrade.service: Succeeded. Apr 07 06:28:22 momsen systemd[1]: Finished Daily apt upgrade and clean activities. /var/crash is empty, so I'm afraid I don't have any information about the netplan generator segfault. I tried running systemctl daemon-reload to see if I could provoke a crash again, and either that command doesn't run all the generators, or the netplan generator failed to crash. Or maybe something was broken during the nightly unattended upgrade on Apr 7 causing the crash -- e.g. I find it somewhat suspicious that /var/log/apt/history.log shows netplan.io and libnetplan0 being upgraded in separate transactions? Start-Date: 2021-04-07 06:27:59 Commandline: /usr/bin/unattended-upgrade Upgrade: libnetplan0:amd64 (0.101-0ubuntu3~20.04.2, 0.102-0ubuntu1~20.04.1) End-Date: 2021-04-07 06:27:59 Start-Date: 2021-04-07 06:28:01 Commandline: /usr/bin/unattended-upgrade Upgrade: libsystemd0:amd64 (245.4-4ubuntu3.5, 245.4-4ubuntu3.6), systemd-timesyncd:amd64 (245.4-4ubuntu3.5, 245.4-4ubuntu3.6), systemd-sysv:amd64 (245.4-4ubuntu3.5, 245.4-4ubuntu3.6), libpam-systemd:amd64 (245.4-4ubuntu3.5, 245.4-4ubuntu3.6), systemd:amd64 (245.4-4ubuntu3.5, 245.4-4ubuntu3.6), libnss-systemd:amd64 (245.4-4ubuntu3.5, 245.4-4ubuntu3.6) End-Date: 2021-04-07 06:28:05 Start-Date: 2021-04-07 06:28:07 Commandline: /usr/bin/unattended-upgrade Upgrade: udev:amd64 (245.4-4ubuntu3.5, 245.4-4ubuntu3.6), libudev1:amd64 (245.4-4ubuntu3.5, 245.4-4ubuntu3.6) End-Date: 2021-04-07 06:28:18 Start-Date: 2021-04-07 06:28:20 Commandline: /usr/bin/unattended-upgrade Upgrade: netplan.io:amd64 (0.101-0ubuntu3~20.04.2, 0.102-0ubuntu1~20.04.1) End-Date: 2021-04-07 06:28:21 I'm sorry for the rambling bug report. I don't know how to make it better. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: netplan.io 0.102-0ubuntu1~20.04.1 ProcVersionSignature: Ubuntu 5.4.0-70.78-generic 5.4.94 Uname: Linux 5.4.0-70-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.16 Architecture: amd64 CasperMD5CheckResult: skip Date: Mon Apr 12 13:37:27 2021 ProcEnviron: LC_CTYPE=lt_LT.UTF-8 TERM=xterm-256color PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: netplan.io UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: netplan.io (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug focal -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1923445 Title: netplan generator segfaults, leaves server with no working DNS To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/netplan.io/+bug/1923445/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs