OS provided by AKS is currently Ubuntu 16.04.6 LTS, kernel 4.15.0-1077-azure.
Every block written by a k8s pod to a ceph CSI volume generates 2 warning lines in the node's system logs (kern.log, syslog, messages, warn):
"Apr 24 09:37:46 aks-<nodename> kernel: [242123.654538] ceph: Failed to find inode for 1"
Under production load, eventually the node succumbs to DiskPressure as the drive fills up. Also performance is noticeably degraded.
Background here: https://tracker.ceph.com/issues/45283
Luis Hernandez indicates 4 commits relating to this issue, just 2 of which have been backported to Ubuntu 16.
d557c48db730 ("ceph: quota: add counter for snaprealms with quota") <==
e3161f17d926 ("ceph: quota: cache inode pointer in ceph_snap_realm")
0eb6bbe4d9cf ("ceph: fix root quota realm check") <==
2596366907f8 ("ceph: don't check quota for snap inode")
Quoth Luis:
"I've done a quick test and, after compiling the bionic kernel 4.15.0-96.97 (the latest released), I can reproduce the issue. Cherry-picking the 2 missing commits (2596366907f8 and e3161f17d926) fixes it."
In my testing Ubuntu 18 does not exhibit the bug, but Azure support tells me it will be months before they make it GA in AKS.
Can we get those commits backported to Ubuntu 16?
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-azure (not installed)
ProcVersionSignature: Ubuntu 4.15.0-1077.82-azure 4.15.18
Uname: Linux 4.15.0-1077-azure x86_64
ApportVersion: 2.20.1-0ubuntu2.23
Architecture: amd64
Date: Wed Apr 29 12:45:12 2020
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: linux-meta-azure
UpgradeStatus: No upgrade log present (probably fresh install)
---
AlsaDevices: Error: command ['ls', '-l', '/dev/snd/'] failed with exit code 2: ls: cannot access '/dev/snd/': No such file or directory
AplayDevices: Error: [Errno 2] No such file or directory
ApportVersion: 2.20.1-0ubuntu2.23
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory
CRDA: N/A
DistroRelease: Ubuntu 16.04
IwConfig: Error: [Errno 2] No such file or directory
Lsusb: Error: command ['lsusb'] failed with exit code 1:
MachineType: Microsoft Corporation Virtual Machine
Package: linux-azure-4.15
PciMultimedia:
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB: 0 hyperv_fb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-1082-azure root=UUID=026eedeb-bd55-4fe3-9e65-0f5f76c13202 ro console=tty1 console=ttyS0 earlyprintk=ttyS0 rootdelay=300
ProcVersionSignature: Ubuntu 4.15.0-1082.92~16.04.1-azure 4.15.18
RelatedPackageVersions:
linux-restricted-modules-4.15.0-1082-azure N/A
linux-backports-modules-4.15.0-1082-azure N/A
linux-firmware N/A
RfKill: Error: [Errno 2] No such file or directory
Tags: xenial uec-images xenial uec-images
Uname: Linux 4.15.0-1082-azure x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:
_MarkForUpload: True
dmi.bios.date: 06/02/2017
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 090007
dmi.board.name: Virtual Machine
dmi.board.vendor: Microsoft Corporation
dmi.board.version: 7.0
dmi.chassis.asset.tag: 7783-7084-3265-9085-8269-3286-77
dmi.chassis.type: 3
dmi.chassis.vendor: Microsoft Corporation
dmi.chassis.version: 7.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr090007:bd06/02/2017:svnMicrosoftCorporation:pnVirtualMachine:pvr7.0:rvnMicrosoftCorporation:rnVirtualMachine:rvr7.0:cvnMicrosoftCorporation:ct3:cvr7.0:
dmi.product.name: Virtual Machine
dmi.product.uuid: 2B0B428F-CF5B-3142-8500-028AFD70E74B
dmi.product.version: 7.0
dmi.sys.vendor: Microsoft Corporation
Targeting bionic: