k8s部署Prometheus

Kubernetes (K8s) 是一个流行的容器编排工具，而Prometheus是一个开源的监控和警报系统。在K8s环境中部署Prometheus可以帮助我们监控集群的健康状态和性能指标。本文将介绍在K8s上部署Prometheus的基本流程，并提供相应的代码示例。

总体流程如下：

| 步骤 | 描述 |
| --- | --- |
| 1 | 创建Prometheus配置文件 |
| 2 | 创建Prometheus Deployment |
| 3 | 创建Prometheus Service |
| 4 | 创建Prometheus ConfigMap |
| 5 | 创建Prometheus Rule ConfigMap |
| 6 | 创建Prometheus ServiceMonitor |
| 7 | 部署Prometheus Operator |
| 8 | 验证Prometheus部署 |

接下来，我们将逐步进行这些步骤的讲解。

步骤1：创建Prometheus配置文件

首先，我们需要创建一个Prometheus的配置文件prometheus.yaml，用于定义Prometheus的配置信息。示例内容如下：

```yaml
apiVersion: monitoring.coreos.com/v1
kind: Prometheus
metadata:
name: prometheus
spec:
replicas: 1
version: v2.14.0
serviceAccountName: prometheus
serviceMonitorSelector:
matchLabels:
app: target-app
resources:
requests:
memory: 400Mi
```

步骤2：创建Prometheus Deployment

接下来，我们需要创建一个Deployment来部署Prometheus实例。示例内容如下：

```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: prometheus
spec:
replicas: 1
selector:
matchLabels:
app: prometheus
template:
metadata:
labels:
app: prometheus
spec:
containers:
- name: prometheus
image: prom/prometheus:v2.14.0
args:
- "--config.file=/etc/prometheus/prometheus.yml"
- "--storage.tsdb.path=/prometheus"
- "--web.console.libraries=/etc/prometheus/console_libraries"
- "--web.console.templates=/etc/prometheus/consoles"
ports:
- containerPort: 9090
volumeMounts:
- name: config-volume
mountPath: /etc/prometheus
- name: data-volume
mountPath: /prometheus
volumes:
- name: config-volume
configMap:
name: prometheus-config
- name: data-volume
emptyDir: {}
```

步骤3：创建Prometheus Service

接下来，我们需要创建一个Service来暴露Prometheus的访问入口。示例内容如下：

```yaml
apiVersion: v1
kind: Service
metadata:
name: prometheus-service
spec:
selector:
app: prometheus
ports:
- name: web
port: 80
targetPort: 9090
```

步骤4：创建Prometheus ConfigMap

接下来，我们需要创建一个ConfigMap来存储Prometheus的配置文件。示例内容如下：

```yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: prometheus-config
data:
prometheus.yml: |
global:
scrape_interval: 15s
scrape_timeout: 10s
scrape_configs:
- job_name: 'kubernetes-nodes'
scheme: https
tls_config:
ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token
kubernetes_sd_configs:
- role: node
relabel_configs:
- source_labels: [__meta_kubernetes_node_label_kubernetes_io_hostname]
target_label: node
- source_labels: [__address__, __meta_kubernetes_node_label_kubernetes_io_hostname]
regex: (.+)(?::\d+)?;(.+)
replacement: ${1}:9100
target_label: __address__
action: replace

```

步骤5：创建Prometheus Rule ConfigMap

接下来，我们需要创建一个ConfigMap来存储Prometheus的规则配置文件。示例内容如下：

```yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: prometheus-rule-config
data:
prometheus.rules.yaml: |
groups:
- name: node-exporter.rules
rules:
- alert: NodeMemoryUsage
expr: node_memory_usage_bytes / node_memory_limit_bytes > 0.8
for: 5m
labels:
severity: warning
annotations:
summary: "Memory usage is above 80% on instance {{ $labels.instance }}"
description: "Memory usage is above 80% on instance {{ $labels.instance }}. Please investigate."
```

步骤6：创建Prometheus ServiceMonitor

接下来，我们需要创建一个ServiceMonitor来监控目标应用的指标。示例内容如下：

```yaml
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
name: target-app-monitor
labels:
app: target-app
spec:
selector:
matchLabels:
app: target-app
endpoints:
- port: web
path: /metrics
interval: 30s
```

步骤7：部署Prometheus Operator

Prometheus Operator是一个Kubernetes Operator，它可以帮助我们管理和操作Prometheus及相关组件。可以使用如下命令来部署Prometheus Operator：

```shell
kubectl apply -f https://raw.githubusercontent.com/prometheus-operator/prometheus-operator/v0.42.1/bundle.yaml
```

步骤8：验证Prometheus部署

最后，我们可以通过访问Prometheus的Web界面来验证部署是否成功。使用以下命令获取Prometheus的访问地址：

```shell
kubectl get services prometheus-service
```

将其复制到浏览器中打开，如果能正常访问到Prometheus的界面，则说明部署成功。

至此，我们完成了在K8s上部署Prometheus的流程。通过这样的部署，我们可以监控K8s集群中各个节点的资源使用情况和应用的性能指标。希望这篇文章能够对你理解和实践K8s部署Prometheus有所帮助。