使用 Loki 收集 Traefik 日志
前面我们介绍了 Loki 的实现架构以及 Promtail 的相关配置，本文我们将来介绍如何安装 Loki，并为 Traefik 的日志设置一个可视化的 Dashboard。
首先添加 Loki 的 Chart 仓库：
helm repo add grafana https://grafana.github.io/helm-charts
helm repo update
获取 loki-stack 的 Chart 包并解压：
helm pull grafana/loki-stack --untar --version 2.3.1
loki-stack 这个 Chart 包里面包含所有的 Loki 相关工具依赖，在安装的时候可以根据需要开启或关闭，比如我们想要安装 Grafana，则可以 在安装的时候简单设置 --set grafana.enabled=true 即可。默认情况下 loki、promtail 是自动开启的，也可以根据我们的需要选择使用 filebeat 或者 logstash，同样在 Chart 包根目录下面创建用于安装的 Values 文件：
# values-prod.yaml
loki:
enabled: true
replicas: 1
persistence:
enabled: true
storageClassName: nfs-storage
promtail:
enabled: true
grafana:
enabled: true
service:
type: NodePort
persistence:
enabled: true
storageClassName: nfs-storage
accessModes:
- ReadWriteOnce
size: 1Gi
然后直接使用上面的 Values 文件进行安装即可：
helm upgrade --install loki -n logging -f values-prod.yaml .
Release "loki" does not exist. Installing it now.
NAME: loki
LAST DEPLOYED: Sat May 8 11:58:50 2021
NAMESPACE: logging
STATUS: deployed
REVISION: 1
NOTES:
The Loki stack has been deployed to your cluster. Loki can now be added as a datasource in Grafana.
See http://docs.grafana.org/features/datasources/loki/ for more detail.
安装完成后可以查看 Pod 的状态：
$ kubectl get pods -n logging
NAME READY STATUS RESTARTS AGE
loki-0 1/1 Running 0 153m
loki-grafana-86f4f9cbcc-kls6j 1/1 Running 0 153m
loki-promtail-69w7b 1/1 Running 0 153m
loki-promtail-mzk77 1/1 Running 0 150m
loki-promtail-pnn97 1/1 Running 0 151m
这里我们为 Grafana 设置的 NodePort 类型的 Service：
$ kubectl get svc -n logging
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
loki ClusterIP 10.105.185.97 <none> 3100/TCP 156m
loki-grafana NodePort 10.102.226.255 <none> 80:30029/TCP 156m
loki-headless ClusterIP None <none> 3100/TCP 156m
可以通过 NodePort 端口 30029 访问 Grafana，使用下面的命令获取 Grafana 的登录密码：
kubectl get secret --namespace logging loki-grafana -o jsonpath="{.data.admin-password}" | base64 --decode ; echo
使用用户名 admin 和上面的获取的密码即可登录 Grafana，由于 Helm Chart 已经为 Grafana 配置好了 Loki 的数据源，所以我们可以直接获取到日志数据了。点击左侧 Explore 菜单，然后就可以筛选 Loki 的日志数据了：
我们使用 Helm 安装的 Promtail 默认已经帮我们做好了配置，已经针对 Kubernetes 做了优化，我们可以查看其配置：
$ kubectl get cm loki-promtail -n logging -o yaml
apiVersion: v1
data:
promtail.yaml: |
client:
backoff_config:
max_period: 5m
max_retries: 10
min_period: 500ms
batchsize: 1048576
batchwait: 1s
external_labels: {}
timeout: 10s
positions:
filename: /run/promtail/positions.yaml
server:
http_listen_port: 3101
target_config:
sync_period: 10s
scrape_configs:
- job_name: kubernetes-pods-name
pipeline_stages:
- docker: {}
kubernetes_sd_configs:
- role: pod
relabel_configs:
- source_labels:
- __meta_kubernetes_pod_label_name
target_label: __service__
- source_labels:
- __meta_kubernetes_pod_node_name
target_label: __host__
- action: drop
regex: ''
source_labels:
- __service__
- action: labelmap
regex: __meta_kubernetes_pod_label_(.+)
- action: replace
replacement: $1
separator: /
source_labels:
- __meta_kubernetes_namespace
- __service__
target_label: job
- action: replace
source_labels:
- __meta_kubernetes_namespace
target_label: namespace
- action: replace
source_labels:
- __meta_kubernetes_pod_name
target_label: pod
- action: replace
source_labels:
- __meta_kubernetes_pod_container_name
target_label: container
- replacement: /var/log/pods/*$1/*.log
separator: /
source_labels:
- __meta_kubernetes_pod_uid
- __meta_kubernetes_pod_container_name
target_label: __path__
- job_name: kubernetes-pods-app
pipeline_stages:
- docker: {}
kubernetes_sd_configs:
- role: pod
relabel_configs:
- action: drop
regex: .+
source_labels:
- __meta_kubernetes_pod_label_name
- source_labels:
- __meta_kubernetes_pod_label_app
target_label: __service__
- source_labels:
- __meta_kubernetes_pod_node_name
target_label: __host__
- action: drop
regex: ''
source_labels:
- __service__
- action: labelmap
regex: __meta_kubernetes_pod_label_(.+)
- action: replace
replacement: $1
separator: /
source_labels:
- __meta_kubernetes_namespace
- __service__
target_label: job
- action: replace
source_labels:
- __meta_kubernetes_namespace
target_label: namespace
- action: replace
source_labels:
- __meta_kubernetes_pod_name
target_label: pod
- action: replace
source_labels:
- __meta_kubernetes_pod_container_name
target_label: container
- replacement: /var/log/pods/*$1/*.log
separator: /
source_labels:
- __meta_kubernetes_pod_uid
- __meta_kubernetes_pod_container_name
target_label: __path__
- job_name: kubernetes-pods-direct-controllers
pipeline_stages:
- docker: {}
kubernetes_sd_configs:
- role: pod
relabel_configs:
- action: drop
regex: .+
separator: ''
source_labels:
- __meta_kubernetes_pod_label_name
- __meta_kubernetes_pod_label_app
- action: drop
regex: '[0-9a-z-.]+-[0-9a-f]{8,10}'
source_labels:
- __meta_kubernetes_pod_controller_name
- source_labels:
- __meta_kubernetes_pod_controller_name
target_label: __service__
- source_labels:
- __meta_kubernetes_pod_node_name
target_label: __host__
- action: drop
regex: ''
source_labels:
- __service__
- action: labelmap
regex: __meta_kubernetes_pod_label_(.+)
- action: replace
replacement: $1
separator: /
source_labels:
- __meta_kubernetes_namespace
- __service__
target_label: job
- action: replace
source_labels:
- __meta_kubernetes_namespace
target_label: namespace
- action: replace
source_labels:
- __meta_kubernetes_pod_name
target_label: pod
- action: replace
source_labels:
- __meta_kubernetes_pod_container_name
target_label: container
- replacement: /var/log/pods/*$1/*.log
separator: /
source_labels:
- __meta_kubernetes_pod_uid
- __meta_kubernetes_pod_container_name
target_label: __path__
- job_name: kubernetes-pods-indirect-controller
pipeline_stages:
- docker: {}
kubernetes_sd_configs:
- role: pod
relabel_configs:
- action: drop
regex: .+
separator: ''
source_labels:
- __meta_kubernetes_pod_label_name
- __meta_kubernetes_pod_label_app
- action: keep
regex: '[0-9a-z-.]+-[0-9a-f]{8,10}'
source_labels:
- __meta_kubernetes_pod_controller_name
- action: replace
regex: '([0-9a-z-.]+)-[0-9a-f]{8,10}'
source_labels:
- __meta_kubernetes_pod_controller_name
target_label: __service__
- source_labels:
- __meta_kubernetes_pod_node_name
target_label: __host__
- action: drop
regex: ''
source_labels:
- __service__
- action: labelmap
regex: __meta_kubernetes_pod_label_(.+)
- action: replace
replacement: $1
separator: /
source_labels:
- __meta_kubernetes_namespace
- __service__
target_label: job
- action: replace
source_labels:
- __meta_kubernetes_namespace
target_label: namespace
- action: replace
source_labels:
- __meta_kubernetes_pod_name
target_label: pod
- action: replace
source_labels:
- __meta_kubernetes_pod_container_name
target_label: container
- replacement: /var/log/pods/*$1/*.log
separator: /
source_labels:
- __meta_kubernetes_pod_uid
- __meta_kubernetes_pod_container_name
target_label: __path__
- job_name: kubernetes-pods-static
pipeline_stages:
- docker: {}
kubernetes_sd_configs:
- role: pod
relabel_configs:
- action: drop
regex: ''
source_labels:
- __meta_kubernetes_pod_annotation_kubernetes_io_config_mirror
- action: replace
source_labels:
- __meta_kubernetes_pod_label_component
target_label: __service__
- source_labels:
- __meta_kubernetes_pod_node_name
target_label: __host__
- action: drop
regex: ''
source_labels:
- __service__
- action: labelmap
regex: __meta_kubernetes_pod_label_(.+)
- action: replace
replacement: $1
separator: /
source_labels:
- __meta_kubernetes_namespace
- __service__
target_label: job
- action: replace
source_labels:
- __meta_kubernetes_namespace
target_label: namespace
- action: replace
source_labels:
- __meta_kubernetes_pod_name
target_label: pod
- action: replace
source_labels:
- __meta_kubernetes_pod_container_name
target_label: container
- replacement: /var/log/pods/*$1/*.log
separator: /
source_labels:
- __meta_kubernetes_pod_annotation_kubernetes_io_config_mirror
- __meta_kubernetes_pod_container_name
target_label: __path__
......
这里我们以收集 Traefik 为例，为 Traefik 定制一个可视化的 Dashboard，默认情况下访问日志没有输出到 stdout，我们可以通过在命令行参数中设置 --accesslog=true 来开启，此外我们还可以设置访问日志格式为 json，这样更方便在 Loki 中查询使用：
containers:
- args:
- --accesslog=true
- --accesslog.format=json
......
默认 traefik 的日志输出为 stdout，如果你的采集端是通过读取文件的话，则需要用 filePath 参数将 traefik 的日志重定向到文件目录。
修改完成后正常在 Grafana 中就可以看到 Traefik 的访问日志了：
然后我们还可以导入 Dashboard 来展示 Traefik 的信息：https://grafana.com/grafana/dashboards/13713，在 Grafana 中导入 13713 号 Dashboard：
不过要注意我们需要更改 Dashboard 里面图表的查询语句，将 job 的值更改为你实际的标签，比如我这里采集 Traefik 日志的最终标签为 job="kube-system/traefik"：
此外该 Dashboard 上还出现了 Panel plugin not found: grafana-piechart-panel 这样的提示，这是因为该面板依赖 grafana-piechart-panel 这个插件，我们进入 Grafana 容器内安装重建 Pod 即可：
$ kubectl exec -it loki-grafana-864fc6999c-z9587 -n logging -- /bin/bash
bash-5.0$ grafana-cli plugins install grafana-piechart-panel
installing grafana-piechart-panel @ 1.6.1
from: https://grafana.com/api/plugins/grafana-piechart-panel/versions/1.6.1/download
into: /var/lib/grafana/plugins
✔ Installed grafana-piechart-panel successfully
Restart grafana after installing plugins . <service grafana-server restart>
由于上面我们安装的时候为 Grafana 持久化了数据，所以删掉 Pod 重建即可：
kubectl delete pod loki-grafana-864fc6999c-z9587 -n logging
pod "loki-grafana-864fc6999c-z9587" deleted
最后调整过后的 Traefik Dashboard 大盘效果如下所示：
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