由于“快照过多”错误，备份失败

描述

在备份期间，通过获取卷快照并将其发送到远程位置来备份 Longhorn 卷。如果快照创建问题影响 Longhorn 卷，且该卷的快照计数高于 248，则备份将不会成功。

您可以通过以下方式验证备份是否由于 TooManySnapshots 错误而失败：

• 通过检查 Velero 日志：

   kubectl logs  -n velero -l app.kubernetes.io/name=velero -c velero |grep "Waiting for volumesnapshotcontents"
  

  示例输出：

  time="2023-12-15T08:15:59Z" level=info msg="Waiting for volumesnapshotcontents snapcontent-f073b88e-bd01-40a8-a645-ec929e276cef to have snapshot handle. Retrying in 5s" backup=velero/daily-2 cmd=/plugins/velero-plugin-for-csi logSource="/go/src/velero-plugin-for-csi/internal/util/util.go:182" pluginName=velero-plugin-for-csi
  time="2023-12-15T08:15:59Z" level=info msg="Waiting for volumesnapshotcontents snapcontent-f073b88e-bd01-40a8-a645-ec929e276cef to have snapshot handle. Retrying in 5s" backup=velero/daily-2 cmd=/plugins/velero-plugin-for-csi logSource="/go/src/velero-plugin-for-csi/internal/util/util.go:182" pluginName=velero-plugin-for-csi
  

• 通过检查 Longhorn Pod 日志：

  kubectl logs  -n longhorn-system -l app=csi-snapshotter --tail=-1 |grep "too many snapshots created"
  

  示例输出：

  I1215 08:39:41.707351       1 snapshot_controller.go:291] createSnapshotWrapper: CreateSnapshot for content snapcontent-f073b88e-bd01-40a8-a645-ec929e276cef returned error: rpc error: code = Internal desc = Bad response statusCode [500]. Status [500 Internal Server Error]. Body: [code=Server Error, detail=, message=failed to create snapshot: proxyServer=10.42.7.56:8501 destination=10.42.7.56:10004: failed to snapshot volume: rpc error: code = Unknown desc = failed to create snapshot snapshot-f073b88e-bd01-40a8-a645-ec929e276cef for volume 10.42.7.56:10004: rpc error: code = Unknown desc = too many snapshots created] from [http://longhorn-backend:9500/v1/volumes/pvc-7d89efa4-3d60-4837-a632-f190cd3cd9ed?action=snapshotCreate]
  

解决方案

If you encounter the TooManySnapshots error, you must clean up the snapshots for all the volumes by running the following script. For details on how to automate this operation, see How to automatically clean up Longhorn snapshots.

#!/bin/bash
set -e

# longhorn backend URL
url=
# By default, snapshot older than 10 days will be deleted
days=10

function display_usage() {
	echo "usage: $(basename "$0") [-h] -u longhorn-url -d days"
	echo "  -u	Longhorn URL"
	echo "  -d 	Number of days(should be >0). By default, script will delete snapshot older than 10 days."
	echo "  -h	Print help"
}

while getopts 'hd:u:' flag "$@"; do
	case "${flag}" in
		u)
			url=${OPTARG}
			;;
		d)
			days=${OPTARG}
			[ "$days" ] && [ -z "${days//[0-9]}" ] || { echo "Invalid number of days=$days"; exit 1; }
			;;
		h)
			display_usage
			exit 0
			;;
		:)
			echo "Invalid option: ${OPTARG} requires an argument."
			exit 1
			;;
		*)
			echo "Unexpected option ${flag}"
			exit 1
			;;
	esac
done

[[ -z "$url" ]] && echo "Missing longhorn URL" && exit 1

# check if URL is valid
curl -s --connect-timeout 30 ${url}/v1 >> /dev/null || { echo "Unable to connect to longhorn backend"; exit 1; }

echo "Deleting snapshots older than $days days"

# Fetch list of longhorn volumes
vols=$( (curl -s -X GET ${url}/v1/volumes |jq -r '.data[].name') )

#delete given snapshot for given volume
function delete_snapshot() {
	local vol=$1
	local snap=$2

	[[ -z "$vol" || -z "$snap" ]] && echo "Error: delete_snapshot: Empty argument" && return 1
	curl -s -X POST ${url}/v1/volumes/${vol}?action=snapshotDelete -d '{"name": "'$snap'"}'
	echo "Snapshot=$snap deleted for volume=$vol"
}

#perform cleanup for given volume
function cleanup_volume() {
	local vol=$1
	local deleted_snap=0

	[[ -z "$vol" ]] && echo "Error: cleanup_volume: Empty argument" && return 1

	# fetch list of snapshot
	snaps=$( (curl -s -X POST ${url}/v1/volumes/${vol}?action=snapshotList | jq  -r '.data[] | select(.usercreated==true) | .name' ) )
	for i in ${snaps[@]}; do
		if [[ $i == "volume-head" ]]; then
			continue
		fi

		# calculate date difference for snapshot
		snapTime=$(curl -s -X POST ${url}/v1/volumes/${vol}?action=snapshotGet -d '{"name":"'$i'"}' |jq -r '.created')
		currentTime=$(date "+%s")
		timeDiff=$(($currentTime - ($(date -d $snapTime "+%s")) / 86400))
		if [[ $timeDiff -lt $days ]]; then
			echo "Ignoring snapshot $i, since it is older than $timeDiff days"
			continue
		fi

		#trigger deletion for snapshot
		delete_snapshot $vol $i
		deleted_snap=$((deleted_snap+1))
	done

	if [[ "$deleted_snap" -gt 0 ]]; then
		#trigger purge for volume
		curl -s -X POST ${url}/v1/volumes/${vol}?action=snapshotPurge >> /dev/null
	fi

}

for i in ${vols[@]}; do
	cleanup_volume $i
done

执行上述脚本时，必须传递以下参数：

• -u - Longhorn 后端 URL。要获取 Longhorn 后端 URL，请运行以下命令：

  kubectl get svc -n longhorn-system longhorn-backend -o json | jq -r '.spec | (.clusterIP|tostring) + ":" + (.ports[0].port|tostring)' to fetch URL
  

• -d - 删除快照前的天数。

备注：

要获取受 TooManySnapshots 错误影响的卷的列表，请运行以下命令：

kubectl get volumes -n longhorn-system -o json | jq -r '.items[] | select(([ .status.conditions[] | select(.type == "toomanysnapshots" and .status == "True") ] | length ) == 1 ) | .metadata.name'