Kubernetes轻量级日志工具Loki安装及踩坑记录
Loki简介
Loki是Grafana出品的一个轻量级日志系统，熟悉ELK的都知道ELK使用起来的成本，而且仅仅是日志检索使用ELK的话有点大材小用了。Loki8技术栈中使用了以下组件。
- Promtail
用来将容器日志发送到 Loki 或者 Grafana 服务上的日志收集工具，该工具主要包括发现采集目标以及给日志流添加上 Label 标签 然后发送给 Loki，Promtail 的服务发现是基于 Prometheus 的服务发现机制实现的。 - Loki
受 Prometheus 启发的可以水平扩展、高可用以及支持多租户的日志聚合系统，使用了和 Prometheus 相同的服务发现机制，将标签添加到日志流中而不是构建全文索引，从 Promtail 接收到的日志和应用的 metrics 指标就具有相同的标签集，不仅提供了更好的日志和指标之间的上下文切换，还避免了对日志进行全文索引。 - Grafana
一个用于监控和可视化观测的开源平台，支持非常丰富的数据源，在 Loki 技术栈中它专门用来展示来自 Prometheus 和 Loki 等数据源的时间序列数据，可进行查询、可视化、报警等操作，可以用于创建、探索和共享数据 Dashboard，鼓励数据驱动。
Loki的工作原理如下图所示：
安装
Loki
关于k8s如何创建应用就不再赘述，Loki在接收日志后会对日志数据进行一定的加工整理，因为存储的数据为有状态的，安装时候推荐使用StatefulSet。创建文件loki.yaml，文件内容如下：
apiVersion: v1
kind: ServiceAccount
metadata:
name: loki
namespace: logging
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
name: loki
namespace: logging
rules:
- apiGroups:
- extensions
resourceNames:
- loki
resources:
- podsecuritypolicies
verbs:
- use
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: loki
namespace: logging
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: loki
subjects:
- kind: ServiceAccount
name: loki
---
apiVersion: v1
kind: ConfigMap
metadata:
name: loki
namespace: logging
labels:
app: loki
data:
loki.yaml: |
auth_enabled: false
ingester:
chunk_idle_period: 3m
chunk_block_size: 262144
chunk_retain_period: 1m
max_transfer_retries: 0
lifecycler:
ring:
kvstore:
store: inmemory
replication_factor: 1
limits_config:
enforce_metric_name: false
reject_old_samples: true
reject_old_samples_max_age: 168h
schema_config:
configs:
- from: "2022-05-15"
store: boltdb-shipper
object_store: filesystem
schema: v11
index:
prefix: index_
period: 24h
server:
http_listen_port: 3100
storage_config:
boltdb_shipper:
active_index_directory: /data/loki/boltdb-shipper-active
cache_location: /data/loki/boltdb-shipper-cache
cache_ttl: 24h
shared_store: filesystem
filesystem:
directory: /data/loki/chunks
chunk_store_config:
max_look_back_period: 0s
table_manager:
retention_deletes_enabled: true
retention_period: 48h
compactor:
working_directory: /data/loki/boltdb-shipper-compactor
shared_store: filesystem
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: loki
namespace: logging
labels:
app: loki
spec:
podManagementPolicy: OrderedReady
replicas: 1
selector:
matchLabels:
app: loki
serviceName: loki
updateStrategy:
type: RollingUpdate
template:
metadata:
labels:
app: loki
spec:
serviceAccountName: loki
securityContext:
fsGroup: 10001
runAsGroup: 10001
runAsNonRoot: true
runAsUser: 10001
initContainers: []
containers:
- name: loki
image: grafana/loki:2.3.0
imagePullPolicy: IfNotPresent
args:
- -config.file=/etc/loki/loki.yaml
volumeMounts:
- name: config
mountPath: /etc/loki
- name: loki-storage
mountPath: /data
ports:
- name: http-metrics
containerPort: 3100
protocol: TCP
livenessProbe:
httpGet:
path: /ready
port: http-metrics
scheme: HTTP
initialDelaySeconds: 45
timeoutSeconds: 1
periodSeconds: 10
successThreshold: 1
failureThreshold: 3
readinessProbe:
httpGet:
path: /ready
port: http-metrics
scheme: HTTP
initialDelaySeconds: 45
timeoutSeconds: 1
periodSeconds: 10
successThreshold: 1
failureThreshold: 3
securityContext:
readOnlyRootFilesystem: true
terminationGracePeriodSeconds: 4800
imagePullSecrets:
- name: your-secret
volumes:
- name: config
configMap:
defaultMode: 420
name: loki
volumeClaimTemplates:
- metadata:
name: loki-storage
labels:
app: loki
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 3Gi
volumeMode: Filesystem
---
apiVersion: v1
kind: Service
metadata:
name: loki
namespace: logging
labels:
app: loki
spec:
type: ClusterIP
ports:
- port: 3100
protocol: TCP
name: http-metrics
targetPort: http-metrics
selector:
app: loki
---
apiVersion: v1
kind: Service
metadata:
name: loki-outer
namespace: logging
labels:
app: loki
spec:
type: NodePort
ports:
- port: 3100
protocol: TCP
name: http-metrics
targetPort: http-metrics
nodePort: 32537
selector:
app: loki
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: loki-storage
spec:
capacity:
storage: 5Gi
nfs:
server: yourIP
path: /data/loki
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
volumeMode: FilesystemGrafana
Grafana的功能就不再多说了，YYDS，用来做可视化界面，创建loki-grafana.yml，文件内容如下：
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: grafana-pvc
namespace: logging
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 5Gi
volumeName: grafana-storage
volumeMode: Filesystem
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: grafana-storage
spec:
capacity:
storage: 10Gi
nfs:
server: yourIp
path: /data/loki/grafana
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
volumeMode: Filesystem
---
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: grafana
name: grafana
namespace: logging
spec:
selector:
matchLabels:
app: grafana
template:
metadata:
labels:
app: grafana
spec:
securityContext:
fsGroup: 472
supplementalGroups:
- 0
containers:
- name: grafana
image: grafana/grafana
imagePullPolicy: IfNotPresent
ports:
- containerPort: 3000
name: http-grafana
protocol: TCP
resources:
requests:
cpu: 500m
memory: 1024Mi
limits:
cpu: 1000m
memory: 2048Mi
volumeMounts:
- mountPath: /var/lib/grafana
name: grafana-pv
imagePullSecrets:
- name: your-secret
volumes:
- name: grafana-pv
persistentVolumeClaim:
claimName: grafana-pvc
---
apiVersion: v1
kind: Service
metadata:
name: grafana
namespace: logging
spec:
ports:
- port: 3000
protocol: TCP
targetPort: http-grafana
nodePort: 30339
selector:
app: grafana
type: NodePort
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: grafana-ui
namespace: logging
labels:
k8s-app: grafana
spec:
rules:
- host: your web address
http:
paths:
- path: /
backend:
serviceName: grafana
servicePort: 3000Promtail
Promtail的主要作用是进行日志采集，每个K8s宿主机上所存储的docker容器及日志存储是独立的，和Host绑定，为了可以采集到所有节点Node的数据，官方推荐Promatail使用DaemonSet安装，创建loki-promtail.yml文件，文件内容如下：
apiVersion: v1
kind: ServiceAccount
metadata:
name: loki-promtail
labels:
app: promtail
namespace: logging
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
labels:
app: promtail
name: promtail-clusterrole
namespace: logging
rules:
- apiGroups: [""]
resources:
- nodes
- nodes/proxy
- services
- endpoints
- pods
verbs: ["get", "watch", "list"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: promtail-clusterrolebinding
labels:
app: promtail
namespace: logging
subjects:
- kind: ServiceAccount
name: loki-promtail
namespace: logging
roleRef:
kind: ClusterRole
name: promtail-clusterrole
apiGroup: rbac.authorization.k8s.io
---
apiVersion: v1
kind: ConfigMap
metadata:
name: loki-promtail
namespace: logging
labels:
app: promtail
data:
promtail.yaml: |2-
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:
- namespace
- pod
- __meta_kubernetes_pod_uid
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:
- namespace
- pod
- __meta_kubernetes_pod_uid
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:
- namespace
- pod
- __meta_kubernetes_pod_uid
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:
- namespace
- pod
- __meta_kubernetes_pod_uid
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:
- namespace
- pod
- __meta_kubernetes_pod_uid
target_label: __path__
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: loki-promtail
namespace: logging
labels:
app: promtail
spec:
selector:
matchLabels:
app: promtail
updateStrategy:
rollingUpdate:
maxUnavailable: 1
type: RollingUpdate
template:
metadata:
labels:
app: promtail
spec:
serviceAccountName: loki-promtail
containers:
- name: promtail
image: grafana/promtail:2.3.0
imagePullPolicy: IfNotPresent
args:
- -config.file=/etc/promtail/promtail.yaml
- -client.url=http://loki:3100/loki/api/v1/push
env:
- name: HOSTNAME
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: spec.nodeName
volumeMounts:
- mountPath: /etc/promtail
name: config
- mountPath: /run/promtail
name: run
- mountPath: /var/lib/docker/containers
name: docker
readOnly: true
- mountPath: /var/log/pods
name: pods
readOnly: true
ports:
- containerPort: 3101
name: http-metrics
protocol: TCP
securityContext:
readOnlyRootFilesystem: true
runAsGroup: 0
runAsUser: 0
readinessProbe:
failureThreshold: 5
httpGet:
path: /ready
port: http-metrics
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 1
imagePullSecrets:
- name: your-secret
tolerations:
- effect: NoSchedule
key: node-role.kubernetes.io/master
operator: Exists
volumes:
- name: config
configMap:
defaultMode: 420
name: loki-promtail
- name: run
hostPath:
path: /run/promtail
type: ""
- name: docker
hostPath:
path: /var/lib/docker/containers
- name: pods
hostPath:
path: /var/log/pods在安装过程中最容易遇到问题的应该就是Promtail配置的过程了，首先需要明白其工作原理，Promtail的优势在于如果直接采集Docker容器的日志，可以使用官方提供的模板自动采集，对于应用没有侵入，不需要进行特殊配置。
使用Promtail核心操作在于两步
- 挂载k8s节点宿主机到容器内目录，这一步需要注意Docker的工作目录，默认为
/var/lib/docker/，如果修改了，在挂载目录时需要同步修改。k8s 1.14之前版本为/var/log/pods/，1.14 or later:/ / .log /var/log/pods/。其中num为容器重启的次数，使用_ _ / / .log ls -l命令查看会发现/var/log/pods/中的日志文件为软链接/var/lib/docker/中的文件，因此在挂载时后需要注意。 - 日志文件路径匹配，在进行relabel_configs配置时需要结合容器中的实际地址进行标签设置。
- action: replace
source_labels:
- __meta_kubernetes_pod_container_name
target_label: container
- replacement: /var/log/pods/$1/**/*.log
separator: _
source_labels:
- namespace
- pod
- __meta_kubernetes_pod_uid
target_label: __path__当遇到__path__时会将replacement替换为具体的文件路径，$1表示取source_labels中的第一个参数，在此对应namespace，这里的namespace已经进行了替换，会被拼接为实际的值。
注意事项
Loki的安装使用k8s会很简单，如果使用helm就更简单了，基于笔者使用的环境为内网，所以通过下载离线镜像的方式，在内网私服进行安装，过程很简单，细节是魔鬼。在安装过程中也踩了很多坑，知其然更知其所以然才能避开安装过程中的问题，如果参考了很多博客，安装过程没问题，却依然不能正常使用，那肯定是环境或者配置问题导致的，在此记录，希望遇到相同问题的人可以得到一些帮助。
关于Loki和Promtail安装中涉及到的ConfigMap中的配置项就不再赘述，详细的配置内容可以参考：
- loki-cm: Configuration | Grafana Loki documentation
- promtail-cm: Configuration | Grafana Loki documentation
其他参考资料：
- Loki - Kubernetes 进阶训练营(第2期)
- Grafana学习(loki日志存在错误的label) | Z.S.K.'s Records