最近看到一篇公众号讲了Nginx-ingress-controller的应用。下面有人评论如何做日志持久化，刚好工作上遇到该问题，整理一个方案，仅供参考。
nginx-ingress-controller的日志
nginx-ingress-controller的日志包括三个部分：
- controller日志： 输出到stdout，通过启动参数中的–log_dir可已配置输出到文件，重定向到文件后会自动轮转，但不会自动清理
- accesslog：输出到stdout，通过nginx-configuration中的字段可以配置输出到哪个文件。输出到文件后不会自动轮转或清理
- errorlog：输出到stderr，配置方式与accesslog类似。
给controller日志落盘
- 给nginx-ingress-controller挂一个hostpath： /data/log/nginx_ingress_controller/ 映射到容器里的/var/log/nginx_ingress_controller/ ，
- 给nginx-ingress-controller配置log-dir和logtostderr参数，将日志重定向到/var/log/nginx_ingress_controller/中。
controller的日志需要做定时清理。由于controller的日志是通过klog(k8s.io/klog)输出的，会进行日志滚动，所以我们通过脚本定时清理一定时间之前的日志文件即可。
给nginx日志落盘
修改configmap： nginx-configuration。配置accesslog和errorlog的输出路径，替换默认的stdout和stderr。输出路径我们可以与controller一致，便于查找。
accesslog和errorlog都只有一个日志文件，我们可以使用logrotate进行日志轮转，将输出到宿主机上的日志进行轮转和清理。配置如：
$ cat /etc/logrotate.d/nginx.log
/data/log/nginx_ingress_controller/access.log {
su root list
rotate 7
daily
maxsize 50M
copytruncate
missingok
create 0644 www-data root
}
官方提供的模板中，nginx-ingress-controller默认都是以33这个用户登录启动容器的，因此挂载hostpath路径时存在权限问题。我们需要手动在机器上执行chown -R 33:33 /data/log/nginx_ingress_controller.
自动化ops
nginx日志落盘中，第2、3两点均需要人工运维，有什么解决办法吗？
问题的关键是：有什么办法可以在nginx-ingress-controller容器启动之前加一个hook，将宿主机的指定目录执行chown呢？
可以用initContainer。initcontainer必须在containers中的容器运行前运行完毕并成功退出。利用这一k8s特性，我们开发一个docker image，里面只执行如下脚本：
#!/bin/bash logdir=$LOG_DIR userID=$USER_ID echo "try to set dir: $logdir 's group as $userID" chown -R $userID:$userID $logdir
脚本读取一些环境变量， 确认需要修改哪个目录，改成怎样的user group。
将脚本打包成dockerimage， 放在nginx-ingress-controller的deploy yaml中，作为initcontainers。 注意要对该initcontainer配置环境变量和volumeMount.
再说第二点，我们注意到nginx-ingress-controller的基础镜像中就自带了logrotate，那么问题就简单了，我们将写好的logrotate配置文件以configmap的形式挂载到容器中就可以了。
一个deploy yaml如下：
---
apiVersion: v1
kind: Service
metadata:
name: ingress-nginx
namespace: kube-system
spec:
type: ClusterIP
ports:
- name: http
port: 80
targetPort: 80
protocol: TCP
- name: https
port: 443
targetPort: 443
protocol: TCP
selector:
app: ingress-nginx
---
apiVersion: v1
kind: Service
metadata:
name: default-http-backend
namespace: kube-system
labels:
app: default-http-backend
spec:
ports:
- port: 80
targetPort: 8080
selector:
app: default-http-backend
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: default
namespace: kube-system
spec:
backend:
serviceName: default-http-backend
servicePort: 80
---
kind: ConfigMap
apiVersion: v1
metadata:
name: nginx-configuration
namespace: kube-system
labels:
app: ingress-nginx
data:
use-forwarded-headers: "true"
# 此处配置nginx日志的重定向目标
access-log-path: /var/log/nginx_ingress_controller/access.log
error-log-path: /var/log/nginx_ingress_controller/error.log
---
# 创建一个configmap，配置nginx日志的轮转策略，对应的是nginx日志在容器内的日志文件
apiVersion: v1
data:
nginx.log: |
{{ user_nginx_log.host_path }}/access.log {
rotate {{ user_nginx_log.rotate_count }}
daily
maxsize {{ user_nginx_log.rotate_size }}
minsize 10M
copytruncate
missingok
create 0644 root root
}
{{ user_nginx_log.host_path }}/error.log {
rotate {{ user_nginx_log.rotate_count }}
daily
maxsize {{ user_nginx_log.rotate_size }}
minsize 10M
copytruncate
missingok
create 0644 root root
}
kind: ConfigMap
metadata:
name: nginx-ingress-logrotate
namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
name: tcp-services
namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
name: udp-services
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: nginx-ingress-serviceaccount
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
name: nginx-ingress-clusterrole
rules:
- apiGroups:
- ""
resources:
- configmaps
- endpoints
- nodes
- pods
- secrets
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes
verbs:
- get
- apiGroups:
- ""
resources:
- services
verbs:
- get
- list
- watch
- apiGroups:
- "extensions"
resources:
- ingresses
verbs:
- get
- list
- watch
- apiGroups:
- ""
resources:
- events
verbs:
- create
- patch
- apiGroups:
- "extensions"
resources:
- ingresses/status
verbs:
- update
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: Role
metadata:
name: nginx-ingress-role
namespace: kube-system
rules:
- apiGroups:
- ""
resources:
- configmaps
- pods
- secrets
- namespaces
verbs:
- get
- apiGroups:
- ""
resources:
- configmaps
resourceNames:
# Defaults to "<election-id>-<ingress-class>"
# Here: "<ingress-controller-leader>-<nginx>"
# This has to be adapted if you change either parameter
# when launching the nginx-ingress-controller.
- "ingress-controller-leader-nginx"
verbs:
- get
- update
- apiGroups:
- ""
resources:
- configmaps
verbs:
- create
- apiGroups:
- ""
resources:
- endpoints
verbs:
- get
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
name: nginx-ingress-role-nisa-binding
namespace: kube-system
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: nginx-ingress-role
subjects:
- kind: ServiceAccount
name: nginx-ingress-serviceaccount
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: nginx-ingress-clusterrole-nisa-binding
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: nginx-ingress-clusterrole
subjects:
- kind: ServiceAccount
name: nginx-ingress-serviceaccount
namespace: kube-system
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: ingress-nginx
namespace: kube-system
spec:
selector:
matchLabels:
app: ingress-nginx
template:
metadata:
labels:
app: ingress-nginx
annotations:
prometheus.io/port: '10254'
prometheus.io/scrape: 'true'
spec:
serviceAccountName: nginx-ingress-serviceaccount
tolerations:
- key: dedicated
value: ingress-nginx
effect: NoSchedule
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: "system/ingress"
operator: In
values:
- "true"
dnsPolicy: ClusterFirstWithHostNet
hostNetwork: true
# 配置initcontainer，确保在nginx-ingress-controller容器启动前将日志目录的权限配置好
initContainers:
- name: adddirperm
image: "{{ image_registry.addr }}/{{ image.adddirperm }}"
env:
- name: LOG_DIR
value: /var/log/nginx_ingress_controller
- name: USER_ID
value: "33"
volumeMounts:
- name: logdir
mountPath: /var/log/nginx_ingress_controller
containers:
- name: nginx-ingress-controller
image: "{{ image_registry.addr }}/{{ image.ingress }}"
imagePullPolicy: IfNotPresent
args:
- /nginx-ingress-controller
- --default-backend-service=$(POD_NAMESPACE)/default-http-backend
- --configmap=$(POD_NAMESPACE)/nginx-configuration
- --tcp-services-configmap=$(POD_NAMESPACE)/tcp-services
- --udp-services-configmap=$(POD_NAMESPACE)/udp-services
- --publish-service=$(POD_NAMESPACE)/ingress-nginx
- --annotations-prefix=nginx.ingress.kubernetes.io
# 设置controller日志的输出路径和方式
- --log_dir=/var/log/nginx_ingress_controller
- --logtostderr=false
securityContext:
capabilities:
drop:
- ALL
add:
- NET_BIND_SERVICE
# www-data -> 33
runAsUser: 33
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
ports:
- name: http
containerPort: 80
- name: https
containerPort: 443
resources:
requests:
cpu: 100m
memory: 256Mi
livenessProbe:
failureThreshold: 3
httpGet:
path: /healthz
port: 10254
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 1
readinessProbe:
failureThreshold: 3
httpGet:
path: /healthz
port: 10254
scheme: HTTP
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 1
volumeMounts:
# 配置挂载容器中控制器组件和nginx的日志输出路径
- name: logdir
mountPath: /var/log/nginx_ingress_controller
# 配置nginx日志的logrotate配置挂载路径
- name: logrotateconf
mountPath: /etc/logrotate.d/nginx.log
subPath: nginx.log
volumes:
# 控制器组件和nginx的日志输出路径为宿主机的hostpath
- name: logdir
hostPath:
path: {{ user_nginx_log.host_path }}
type: ""
# nginx日志的轮转配置文件来自于configmap
- name: logrotateconf
configMap:
name: nginx-ingress-logrotate
items:
- key: nginx.log
path: nginx.log
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: default-http-backend
namespace: kube-system
labels:
app: default-http-backend
spec:
selector:
matchLabels:
app: default-http-backend
template:
metadata:
labels:
app: default-http-backend
spec:
terminationGracePeriodSeconds: 60
tolerations:
- key: dedicated
value: ingress-nginx
effect: NoSchedule
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: "system/ingress"
operator: In
values:
- "true"
containers:
- name: default-http-backend
# Any image is permissible as long as:
# 1. It serves a 404 page at /
# 2. It serves 200 on a /healthz endpoint
image: "{{ image_registry.addr }}/{{ image.http_backend }}"
imagePullPolicy: IfNotPresent
livenessProbe:
httpGet:
path: /healthz
port: 8080
scheme: HTTP
initialDelaySeconds: 30
timeoutSeconds: 5
ports:
- containerPort: 8080
resources:
limits:
cpu: 10m
memory: 20Mi
requests:
cpu: 10m
memory: 20Mi
---
最后，有的人建议将initcontainer去掉，改为基于原有的nginx-ingress-controller镜像加一层layer，将配置路径权限的脚本放在该层执行。 个人认为这种方法既不美观，也不方便。唯一的好处仅在于deploy yaml仍然简洁（但少不了volumeMount之类的配置）。不过还是看个人使用感受吧~
