Looks like the restart to enable debug triggered a DHCPDISCOVER, that's the easiest point to use to synchronise the PCAP and the log.
Note logs of successful DHCP ACK messages followed by "Lease lost!". ** Attachment added: "systemd-networkd logs" https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1896229/+attachment/5412184/+files/systemd-networkd.log -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1896229 Title: systemd-networkd thinks it loses its lease every renewal Status in systemd package in Ubuntu: New Bug description: With a server running 20.04 on AWS, I noticed connectivity glitches once per half hour. Eventually managed to correlate it with DHCP renewals. Each time systemd-networkd does a renewal, it logs that the lease was lost and goes through a cycle of removing and re-adding the IP and routes (Even though it's the same IP and routes). This causes disruption, especially to SNATted flows; if a packet arrives for an SNATted flow during hte windows where the IP is removed then (I think) the host sends a RST and the flow gets torn down. (In any case, such flows get lost during the glitch.) I'd expect a DHCP renewal to be completely transparent; the IP shouldn't flap, it should just be updated to have a longer lifetime. I managed to capture a PCAP of the DHCP renewals along with a debug log from systemd-networkd. ProblemType: Bug DistroRelease: Ubuntu 19.10 Package: systemd 242-7ubuntu3.11 ProcVersionSignature: User Name 5.3.0-1030.32-aws 5.3.18 Uname: Linux 5.3.0-1030-aws x86_64 ApportVersion: 2.20.11-0ubuntu8.9 Architecture: amd64 Date: Fri Sep 18 13:05:22 2020 Ec2AMI: ami-0d3d788094d3f0aa9 Ec2AMIManifest: (unknown) Ec2AvailabilityZone: us-west-2a Ec2InstanceType: t3.large Ec2Kernel: unavailable Ec2Ramdisk: unavailable Lsusb: Error: command ['lsusb'] failed with exit code 1: MachineType: Amazon EC2 t3.large ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=C.UTF-8 SHELL=/bin/bash ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.3.0-1030-aws root=PARTUUID=e96a8035-01 ro console=tty1 console=ttyS0 nvme_core.io_timeout=4294967295 panic=-1 SourcePackage: systemd UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/16/2017 dmi.bios.vendor: Amazon EC2 dmi.bios.version: 1.0 dmi.board.asset.tag: i-0fc0b0107c428fe19 dmi.board.vendor: Amazon EC2 dmi.chassis.asset.tag: Amazon EC2 dmi.chassis.type: 1 dmi.chassis.vendor: Amazon EC2 dmi.modalias: dmi:bvnAmazonEC2:bvr1.0:bd10/16/2017:svnAmazonEC2:pnt3.large:pvr:rvnAmazonEC2:rn:rvr:cvnAmazonEC2:ct1:cvr: dmi.product.name: t3.large dmi.sys.vendor: Amazon EC2 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1896229/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
