背景
边缘集群（基于 树莓派 + K3S) 需要实现基本的告警功能。
边缘集群限制
- CPU/内存/存储 资源紧张，无法支撑至少需要 2GB 以上内存和大量存储的基于 Prometheus 的完整监控体系方案（即使是基于 Prometheus Agent, 也无法支撑） （需要避免额外的存储和计算资源消耗）
- 网络条件，无法支撑监控体系，因为监控体系一般都需要每 1min 定时（或每时每刻）传输数据，且数据量不小；
- 存在 5G 收费网络的情况，且访问的目的端地址需要开通权限，且按照流量收费，且因为 5G 网络条件，网络传输能力受限，且不稳定（可能会在一段时间内离线）;
关键需求
总结下来，关键需求如下：
- 实现对边缘集群异常的及时告警，需要知道边缘集群正在发生的异常情况；
- 网络：网络条件情况较差，网络流量少，只只能开通极少数目的端地址，可以容忍网络不稳定（一段时间内离线）的情况；
- 资源：需要尽量避免额外的存储和计算资源消耗
方案
综上所诉，采用如下方案实现：
基于 Kubernetes Events 的告警通知
架构图
技术方案规划
- 从 Kubernetes 的各项资源收集 Events, 如：
- pod
- node
- kubelet
- crd
- ...
- 通过 kubernetes-event-exporter 组件来实现对 Kubernetes Events 的收集；
- 只筛选
Warning级别 Events 供告警通知（后续，条件可以进一步定义） - 告警通过 飞书 webhook 等通信工具进行发送（后续，发送渠道可以增加）
实施步骤
手动方式：
在边缘集群上，执行如下操作：
1. 创建 roles
如下：
cat << _EOF_ | kubectl apply -f - --- apiVersion: v1 kind: Namespace metadata: name: monitoring --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata: name: event-exporter-extra rules: - apiGroups: - "" resources: - nodes verbs: - get - list - watch --- apiVersion: v1 kind: ServiceAccount metadata: namespace: monitoring name: event-exporter --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: event-exporter roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: view subjects: - kind: ServiceAccount namespace: monitoring name: event-exporter --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: event-exporter-extra roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: event-exporter-extra subjects: - kind: ServiceAccount namespace: kube-event-export name: event-exporter _EOF_ 2. 创建 kubernetes-event-exporter config
如下：
cat << _EOF_ | kubectl apply -f - apiVersion: v1 kind: ConfigMap metadata: name: event-exporter-cfg namespace: monitoring data: config.yaml: | logLevel: error logFormat: json route: routes: - match: - receiver: "dump" - drop: - type: "Normal" match: - receiver: "feishu" receivers: - name: "dump" stdout: {} - name: "feishu" webhook: endpoint: "https://open.feishu.cn/open-apis/bot/v2/hook/..." headers: Content-Type: application/json layout: msg_type: interactive card: config: wide_screen_mode: true enable_forward: true header: title: tag: plain_text content: XXX IoT K3S 集群告警 template: red elements: - tag: div text: tag: lark_md content: "**EventType:** {{ .Type }}n**EventKind:** {{ .InvolvedObject.Kind }}n**EventReason:** {{ .Reason }}n**EventTime:** {{ .LastTimestamp }}n**EventMessage:** {{ .Message }}" _EOF_ 🐾 注意：
endpoint: "https://open.feishu.cn/open-apis/bot/v2/hook/..."按需修改为对应的 webhook endpoint, ❌切记勿对外公布！!!content: XXX IoT K3S 集群告警: 按需调整为方便快速识别的名称，如："家里测试 K3S 集群告警"
3. 创建 Deployment
cat << _EOF_ | kubectl apply -f - apiVersion: apps/v1 kind: Deployment metadata: name: event-exporter namespace: monitoring spec: replicas: 1 selector: matchLabels: app: event-exporter version: v1 template: metadata: labels: app: event-exporter version: v1 spec: volumes: - name: cfg configMap: name: event-exporter-cfg defaultMode: 420 - name: localtime hostPath: path: /etc/localtime type: '' - name: zoneinfo hostPath: path: /usr/share/zoneinfo type: '' containers: - name: event-exporter image: ghcr.io/opsgenie/kubernetes-event-exporter:v0.11 args: - '-conf=/data/config.yaml' env: - name: TZ value: Asia/Shanghai volumeMounts: - name: cfg mountPath: /data - name: localtime readOnly: true mountPath: /etc/localtime - name: zoneinfo readOnly: true mountPath: /usr/share/zoneinfo imagePullPolicy: IfNotPresent serviceAccount: event-exporter affinity: nodeAffinity: preferredDuringSchedulingIgnoredDuringExecution: - weight: 100 preference: matchExpressions: - key: node-role.kubernetes.io/controlplane operator: In values: - 'true' - weight: 100 preference: matchExpressions: - key: node-role.kubernetes.io/control-plane operator: In values: - 'true' - weight: 100 preference: matchExpressions: - key: node-role.kubernetes.io/master operator: In values: - 'true' tolerations: - key: node-role.kubernetes.io/controlplane value: 'true' effect: NoSchedule - key: node-role.kubernetes.io/control-plane operator: Exists effect: NoSchedule - key: node-role.kubernetes.io/master operator: Exists effect: NoSchedule _EOF_ 📝 说明：
event-exporter-cfg相关配置，是用于加载以 ConfigMap 形式保存的配置文件；localtimezoneinfoTZ相关配置，是用于修改该 pod 的时区为Asia/Shanghai, 以使得最终显示的通知效果为 CST 时区；affinitytolerations相关配置，是为了确保：无论如何，优先调度到 master node 上去，按需调整，此处是因为 master 往往在边缘集群中作为网关存在，配置较高，且在线时间较长；
自动化部署
效果：安装 K3S 时就自动部署
在 K3S server 所在节点，/var/lib/rancher/k3s/server/manifests/ 目录（如果没有该目录就先创建）下，创建 event-exporter.yaml
--- apiVersion: v1 kind: Namespace metadata: name: monitoring --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata: name: event-exporter-extra rules: - apiGroups: - "" resources: - nodes verbs: - get - list - watch --- apiVersion: v1 kind: ServiceAccount metadata: namespace: monitoring name: event-exporter --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: event-exporter roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: view subjects: - kind: ServiceAccount namespace: monitoring name: event-exporter --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: event-exporter-extra roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: event-exporter-extra subjects: - kind: ServiceAccount namespace: kube-event-export name: event-exporter --- apiVersion: v1 kind: ConfigMap metadata: name: event-exporter-cfg namespace: monitoring data: config.yaml: | logLevel: error logFormat: json route: routes: - match: - receiver: "dump" - drop: - type: "Normal" match: - receiver: "feishu" receivers: - name: "dump" stdout: {} - name: "feishu" webhook: endpoint: "https://open.feishu.cn/open-apis/bot/v2/hook/dc4fd384-996b-4d20-87cf-45b3518869ec" headers: Content-Type: application/json layout: msg_type: interactive card: config: wide_screen_mode: true enable_forward: true header: title: tag: plain_text content: xxxK3S集群告警 template: red elements: - tag: div text: tag: lark_md content: "**EventType:** {{ .Type }}n**EventKind:** {{ .InvolvedObject.Kind }}n**EventReason:** {{ .Reason }}n**EventTime:** {{ .LastTimestamp }}n**EventMessage:** {{ .Message }}" --- apiVersion: apps/v1 kind: Deployment metadata: name: event-exporter namespace: monitoring spec: replicas: 1 selector: matchLabels: app: event-exporter version: v1 template: metadata: labels: app: event-exporter version: v1 spec: volumes: - name: cfg configMap: name: event-exporter-cfg defaultMode: 420 - name: localtime hostPath: path: /etc/localtime type: '' - name: zoneinfo hostPath: path: /usr/share/zoneinfo type: '' containers: - name: event-exporter image: ghcr.io/opsgenie/kubernetes-event-exporter:v0.11 args: - '-conf=/data/config.yaml' env: - name: TZ value: Asia/Shanghai volumeMounts: - name: cfg mountPath: /data - name: localtime readOnly: true mountPath: /etc/localtime - name: zoneinfo readOnly: true mountPath: /usr/share/zoneinfo imagePullPolicy: IfNotPresent serviceAccount: event-exporter affinity: nodeAffinity: preferredDuringSchedulingIgnoredDuringExecution: - weight: 100 preference: matchExpressions: - key: node-role.kubernetes.io/controlplane operator: In values: - 'true' - weight: 100 preference: matchExpressions: - key: node-role.kubernetes.io/control-plane operator: In values: - 'true' - weight: 100 preference: matchExpressions: - key: node-role.kubernetes.io/master operator: In values: - 'true' tolerations: - key: node-role.kubernetes.io/controlplane value: 'true' effect: NoSchedule - key: node-role.kubernetes.io/control-plane operator: Exists effect: NoSchedule - key: node-role.kubernetes.io/master operator: Exists effect: NoSchedule 之后启动 K3S 就会自动部署。
📚️Reference:
自动部署 manifests 和 Helm charts | Rancher 文档
最终效果
如下图：
📚️参考文档
- opsgenie/kubernetes-event-exporter: Export Kubernetes events to multiple destinations with routing and filtering (github.com)
- AliyunContainerService/kube-eventer: kube-eventer emit kubernetes events to sinks (github.com)
- kubesphere/kube-events: K8s Event Exporting, Filtering and Alerting in Multi-Tenant Environment (github.com)
- kubesphere/notification-manager: K8s native notification management with multi-tenancy support (github.com)
三人行, 必有我师; 知识共享, 天下为公. 本文由东风微鸣技术博客 EWhisper.cn 编写.
