[Release-1.29] - Multiple simultaneous snapshots result in silent failure and/or corruption of at least one snapshot

[brandond]

Backport fix for Multiple simultaneous snapshots result in silent failure and/or corruption of at least one snapshot

• Multiple simultaneous snapshots result in silent failure and/or corruption of at least one snapshot #10371

[fmoral2]

Validated on Version:

-$ k3s version v1.29.6-rc3+k3s1 (83ae095a) 

Environment Details

Infrastructure
Cloud EC2 instance

Node(s) CPU architecture, OS, and Version:
ubuntu
AMD

Cluster Configuration:
-3 node server
-1 node agents

Steps to validate the fix

1. Install k3s etcd embedded
2. Take etcd snapshot more than once at the same time
3. validate error response

Reproduction Issue:

 

 k3s -v
k3s version v1.27.15-rc1+k3s1 (102e42a5)
go version go1.21.11


k3s etcd-snapshot save & k3s etcd-snapshot save; sleep 5

WARN[0000] Unknown flag --write-kubeconfig-mode found in config.yaml, skipping 
WARN[0000] Unknown flag --tls-san found in config.yaml, skipping 
WARN[0000] Unknown flag --cluster-init found in config.yaml, skipping 
WARN[0000] Unknown flag --protect-kernel-defaults found in config.yaml, skipping 
WARN[0000] Unknown flag --selinux found in config.yaml, skipping 
WARN[0000] Unknown flag --node-external-ip found in config.yaml, skipping 
WARN[0000] Unknown flag --node-ip found in config.yaml, skipping 
WARN[0000] Unknown flag --secrets-encryption found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-apiserver-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-apiserver-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-apiserver-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-apiserver-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-apiserver-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-apiserver-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-apiserver-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-apiserver-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-apiserver-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-controller-manager-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kube-controller-manager-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kubelet-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --kubelet-arg found in config.yaml, skipping 
WARN[0000] Unknown flag --node-label found in config.yaml, skipping 
WARN[0000] Unknown flag --node-label found in config.yaml, skipping 
WARN[0000] Unknown flag --node-label found in config.yaml, skipping 
FATA[0000] see server log for details: Internal error occurred: etcd-snapshot error ID 20267 
INFO[0000] Snapshot on-demand-ip- us-east-2.compute.internal-1719002637 saved. 
[1]+  Done                    k3s etcd-snapshot save



$ journalctl -xeu k3s.service | grep "snapshot"

Jun 21 20:23:09 ip- k3s[13884]: time="2024-06-21T20:23:09Z" level=error msg="Failed to take etcd snapshot: could not rename /var/lib/rancher/k3s/server/db/snapshots/on-demand-ip- .us-east-2.compute.internal-1719001390.part to /var/lib/rancher/k3s/server/db/snapshots/on-demand-ip-1 .us-east-2.compute.internal-1719001390 (rename /var/lib/rancher/k3s/server/db/snapshots/on-demand-ip- .us-east-2.compute.internal-1719001390.part /var/lib/rancher/k3s/server/db/snapshots/on-demand-ip- us-east-2.compute.internal-1719001390: no such file or directory)"
Jun 21 20:23:09 ip-  k3s[13884]: I0621 20:23:09.912916   13884 event.go:307] "Event occurred" object="local-on-demand-ip- .us-east-2.compute.internal-1719001390-c93945" fieldPath="" kind="ETCDSnapshotFile" apiVersion="k3s.cattle.io/v1" type="Warning" reason="ETCDSnapshotFailed" message="Failed to save snapshot on-demand-ip-1 .us-east-2.compute.internal-1719001390 on ip-1 .us-east-2.compute.internal: could not rename /var/lib/rancher/k3s/server/db/snapshots/on-demand-ip- us-east-2.compute.internal-1719001390.part to /var/lib/rancher/k3s/server/db/snapshots/on-demand-ip- us-east-2.compute.internal-1719001390 (rename /var/lib/rancher/k3s/server/db/snapshots/on-demand-ip-1 us-east-2.compute.internal-1719001390.part /var/lib/rancher/k3s/server/db/snapshots/on-demand-ip-172-31-1-64.us-east-2.compute.internal-1719001390: no such file or directory)"

Validation Results:

 
 




k3s etcd-snapshot save & k3s etcd-snapshot save; sleep 5
WARN[0000] Unknown flag --node-label found in config.yaml, skipping 
FATA[0000] see server log for details: Internal error occurred: etcd-snapshot error ID 14248 
INFO[0000] Snapshot on-demand-ip- us-east-2.compute.internal-1719002640 saved. 
[1]+  Exit 1                  k3s etcd-snapshot save

$ journalctl -xeu k3s.service | grep "snapshot"

 Jun 21 20:20:01 ip- k3s[13083]: time="2024-06-21T20:20:01Z" level=info msg="Starting managed etcd snapshot ConfigMap controller"
Jun 21 20:20:02 ip-  k3s[13083]: time="2024-06-21T20:20:02Z" level=info msg="Reconciling snapshot ConfigMap data"
Jun 21 20:22:52 ip- k3s[13083]: time="2024-06-21T20:22:52Z" level=info msg="Saving etcd snapshot to /var/lib/rancher/k3s/server/db/snapshots/on-demand-ip-172-31-7-229.us-east-2.compute.internal-1719001372"
Jun 21 20:22:52 ip-  k3s[13083]: {"level":"info","ts":"2024-06-21T20:22:52.098617Z","logger":"etcd-client","caller":"snapshot/v3_snapshot.go:65","msg":"created temporary db file","path":"/var/lib/rancher/k3s/server/db/snapshots/on-demand-ip- .us-east-2.compute.internal-1719001372.part"}
Jun 21 20:22:52 ip-  k3s[13083]: {"level":"info","ts":"2024-06-21T20:22:52.101602Z","logger":"etcd-client.client","caller":"v3@v3.5.13-k3s1/maintenance.go:212","msg":"opened snapshot stream; downloading"}
Jun 21 20:22:52 ip- k3s[13083]: {"level":"info","ts":"2024-06-21T20:22:52.101781Z","logger":"etcd-client","caller":"snapshot/v3_snapshot.go:73","msg":"fetching snapshot","endpoint":"https://127.0.0.1:2379"}
Jun 21 20:22:52 ip-1 k3s[13083]: {"level":"info","ts":"2024-06-21T20:22:52.111894Z","caller":"v3rpc/maintenance.go:126","msg":"sending database snapshot to client","total-bytes":5713920,"size":"5.7 MB"}
Jun 21 20:22:52 ip-  k3s[13083]: time="2024-06-21T20:22:52Z" level=error msg="etcd-snapshot error ID 11914: snapshot save already in progress"
Jun 21 20:22:52 ip-  k3s[13083]: time="2024-06-21T20:22:52Z" level=error msg="Sending HTTP 500 response to 127.0.0.1:50686: etcd-snapshot error ID 11914"
Jun 21 20:22:52 ip- k3s[13083]: {"level":"info","ts":"2024-06-21T20:22:52.160236Z","caller":"v3rpc/maintenance.go:175","msg":"successfully sent database snapshot to client","total-bytes":5713920,"size":"5.7 MB","took":"now"}