一层Nginx反向代理K8S化部署实践

目录:

1)背景介绍
2)方案分析
3)实现细节
4)监控告警
5)日志收集
6)测试
一、背景介绍
如下图所示,传统方式部署一层Nginx,随着业务扩大,维护管理变得复杂,繁琐,耗时耗力和易出错等问题。我们的Nginx是有按照业务来分组的,不同的业务使用不同分组的Nginx实例区分开。通过nginx.conf中include不同分组的配置文件来实现。

图片

如果有一种方式可以简化Nginx的部署,扩缩容的管理。日常只需关注nginx的配置文件发布上线即可。当前最受欢迎的管理模式莫过于容器化部署,而nginx本身也是无状态服务,非常适合这样的场景。于是,通过一个多月的设计,实践,测试。最终实现了Nginx的“上云”。

二、方案分析
1)架构图如下所示:

2)整体流程:
在发布机(nginx003)上的对应目录修改配置后,推送最新配置到gitlab仓库,我们会有一个reloader的
容器,每10s 拉取gitlab仓库到本地pod,pod中会根据nginx.conf文件include的
对象 /usr/local/nginx/conf-configmap/中是否有include该分组来判断是否进行reload 。
三、实现细节
在K8S上部署Nginx实例,由于Nginx是有分组管理的。所以我们使用一个Deployment对应一个分组,Deployment的yaml声明文件除了名称和引用的include文件不一样之外,其他的配置都是一样的。 一个Deployment根据分组的业务负载了来设定replicas数量,每个pod由四个容器组成。包括:1个initContainer容器init-reloader和3个业务容器nginx,reloader和nginx-exporter。下面,我们着重分析每个容器实现的功能。
1)init-reloader容器
这个容器是一个initContainer容器,是做一些初始化的工作。
1.1)镜像:

cat Dockerfile

FROM fulcrum/ssh-git:latest

COPY init-start.sh /init-start.sh
COPY start.sh /start.sh
COPY Dockerfile /Dockerfile
RUN apk add –no-cache tzdata ca-certificates libc6-compat inotify-tools bc bash && echo ‘hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4’ >> /etc/nsswitch.conf && ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime && echo “Asia/Shanghai” >> /etc/timezone
1.2)执行init-start.sh脚本

功能:
(1)从仓库拉取最新配置并cp 至/usr/local/nginx/conf.d/目录
(2)创建代理缓存相关的目录/data/proxy_cache_path/
(3)在/usr/local/nginx/conf/servers/下创建对应的对应的conf 文件记录后端服务 realserver:port

2)nginx-exporter容器
该容器是实现对接prometheus监控nginx的exporter
2.1)镜像:

cat Dockerfile

FROM busybox:1.28

COPY nginx_exporter /nginx_exporter/nginx_exporter
COPY start.sh /start.sh
ENV start_cmd=”/nginx_exporter/nginx_exporter -nginx.scrape-uri http://127.0.0.1:80/ngx_status”
2.2)执行start.sh脚本

功能
(1) num=$(netstat -anlp | grep -w 80 | grep nginx | grep LISTEN | wc -l)
(2) /nginx_exporter/nginx_exporter -nginx.scrape-uri http://127.0.0.1:80/ngx_status

3)nginx容器
该容器是openresty实例的业务容器
3.1)镜像

FROM centos:7.3.1611

COPY Dockerfile /dockerfile/

COPY sysctl.conf /etc/sysctl.conf

USER root
RUN yum install -y logrotate cronie initscripts bc wget git && yum clean all
ADD nginx /etc/logrotate.d/nginx
ADD root /var/spool/cron/root
ADD kill_shutting_down.sh /kill_shutting_down.sh
ADD etc-init.d-nginx /etc-init.d-nginx
COPY openresty.zip /usr/local/openresty.zip
COPY start.sh /start.sh
COPY reloader-start.sh /reloader-start.sh
RUN chmod +x /start.sh /kill_shutting_down.sh reloader-start.sh && unzip /usr/local/openresty.zip -d /usr/local/ && cd /usr/local/openresty && echo “y” | bash install.sh && rm -rf /usr/local/openresty /var/cache/yum && localedef -c -f UTF-8 -i zh_CN zh_CN.utf8 && mkdir -p /usr/local/nginx/conf/servers && chmod -R 777 /usr/local/nginx/conf/servers && cp -f /etc-init.d-nginx /etc/init.d/nginx && chmod +x /etc/init.d/nginx

ENTRYPOINT [“/start.sh”]
3.2)执行start.sh脚本

功能:
(1)启动crond定时任务实现日志轮转
(2)判断目录(/usr/local/nginx/conf.d) 不为空,启动nginx

4)reloader容器
改容器是实现发布流程逻辑的辅助容器
4.1)镜像和nginx容器一样
4.2)执行reloader-start.sh脚本

功能:
(1)get_reload_flag函数
通过对比/gitrepo/diff.files 文件 改变的文件名和/usr/local/nginx/conf-configmap/中 是否include 此文件名发生改变的分组 来判断是否需要reload (flag=1 则reload)

(2)check_mem函数
判断内存少于30% 返回1

(3)kill_shutting_down函数
先执行内存剩余量判断,如果小于30%,杀掉shutdown 进程

(4)nginx_force_reload函数(只会进行reload)
kill -HUP ${nginxpid}

(5)reload函数
(5.1) 首先将仓库中的配置文件cp至/usr/local/nginx/conf.d ;
(5.2) /usr/local/nginx/conf.d不为空时
创建proxy_cache_path 目录—/usr/local/nginx/conf/servers/文件— nginx -t —kill_shutting_down —–nginx_force_reload

总结整体实现流程如下 :
1)拉取仓库pull 重命名旧的commit id 文件(/gitrepo/local_current_commit_id.old),并生成获取新的commit id(/gitrepo/local_current_commit_id.new);
2)通过对比old和new commit id 获得发生了变更文件到/gitrepo/diff.files ;
3)然后调用 et_reload_flag 判断改组nginx是否需要reload
4)如果/gitrepo/diff.files中有“nginx_force_reload” 字段 然后kill_shutting_down — nginx_force_reload
5)Deployment的实现

通过实现以上容器的功能后,打包成镜像用于部署。以下是Deployment的yaml详细内容:

apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: slb-nginx-group01
name: slb-nginx-group01
namespace: slb-nginx
spec:
replicas: 3 // 3个副本数,即:3个pod
selector:
matchLabels:
app: slb-nginx-group01
strategy: // 滚动更新的策略,
rollingUpdate:
maxSurge: 25%
maxUnavailable: 1
type: RollingUpdate
template:
metadata:
labels:
app: slb-nginx-group01
exporter: nginx
annotations: // 注解,实现和prometheus的对接
prometheus.io/path: /metrics
prometheus.io/port: “9113”
prometheus.io/scrape: “true”
spec:
nodeSelector: // 节点label选择
app: slb-nginx-label-group01
tolerations: // 容忍度设置
– key: “node-type”
operator: “Equal”
value: “slb-nginx-label-group01”
effect: “NoExecute”
affinity: // pod的反亲和性,尽量部署到阿里云不同的可用区
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
– weight: 100
podAffinityTerm:
labelSelector:
matchExpressions:
– key: app
operator: In
values:
– slb-nginx-group01
topologyKey: “failure-domain.beta.kubernetes.io/zone”
shareProcessNamespace: true // 容器间进程空间共享
hostAliases: // 设置hosts
– ip: “xxx.xxx.xxx.xxx”
hostnames:
– “www.test.com”
initContainers:
– image: www.test.com/library/reloader:v0.0.1
name: init-reloader
command: [“/bin/sh”]
args: [“/init-start.sh”]
env:
– name: nginx_git_repo_address
value: “git@www.test.com:psd/nginx-conf.git”
volumeMounts:
– name: code-id-rsa
mountPath: /root/.ssh/code_id_rsa
subPath: code_id_rsa
– name: nginx-shared-confd
mountPath: /usr/local/nginx/conf.d/
– name: nginx-gitrepo
mountPath: /gitrepo/
containers:
– image: www.test.com/library/nginx-exporter:v0.4.2
name: nginx-exporter
command: [“/bin/sh”, “-c”, “/start.sh”]
resources:
limits:
cpu: 50m
memory: 50Mi
requests:
cpu: 50m
memory: 50Mi
volumeMounts:
– name: time-zone
mountPath: /etc/localtime
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
– image: www.test.com/library/openresty:1.13.6
name: nginx
command: [“/bin/sh”, “-c”, “/start.sh”]
lifecycle:
preStop:
exec:
command:
– sh
– -c
– sleep 10
livenessProbe:
failureThreshold: 3
initialDelaySeconds: 90
periodSeconds: 3
successThreshold: 1
httpGet:
path: /healthz
port: 8999
timeoutSeconds: 4
readinessProbe:
failureThreshold: 3
initialDelaySeconds: 4
periodSeconds: 3
successThreshold: 1
tcpSocket:
port: 80
timeoutSeconds: 4
resources:
limits:
cpu: 8
memory: 8192Mi
requests:
cpu: 2
memory: 8192Mi
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
– name: nginx-start-shell
mountPath: /start.sh
subPath: start.sh
readOnly: true
– name: conf-include
mountPath: /usr/local/nginx/conf-configmap/
– name: nginx-shared-confd
mountPath: /usr/local/nginx/conf.d/
– name: nginx-logs
mountPath: /data/log/nginx/
– name: data-nfs-webroot
mountPath: /data_nfs/WebRoot
– name: data-nfs-httpd
mountPath: /data_nfs/httpd
– name: data-nfs-crashdump
mountPath: /data_nfs/crashdump
– name: data-cdn
mountPath: /data_cdn
– image: www.test.com/library/openresty:1.13.6
name: reloader
command: [“/bin/sh”, “-c”, “/reloader-start.sh”]
env:
– name: nginx_git_repo_address
value: “git@www.test.com:psd/nginx-conf.git”
– name: MY_MEM_LIMIT
valueFrom:
resourceFieldRef:
containerName: nginx
resource: limits.memory
securityContext:
capabilities:
add:
– SYS_PTRACE
resources:
limits:
cpu: 100m
memory: 550Mi
requests:
cpu: 100m
memory: 150Mi
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
– name: code-id-rsa
mountPath: /root/.ssh/code_id_rsa
subPath: code_id_rsa
readOnly: true
– name: reloader-start-shell
mountPath: /reloader-start.sh
subPath: reloader-start.sh
readOnly: true
– name: conf-include
mountPath: /usr/local/nginx/conf-configmap/
– name: nginx-shared-confd
mountPath: /usr/local/nginx/conf.d/
– name: nginx-gitrepo
mountPath: /gitrepo/
volumes:
– name: code-id-rsa
configMap:
name: code-id-rsa
defaultMode: 0600
– name: nginx-start-shell
configMap:
name: nginx-start-shell
defaultMode: 0755
– name: reloader-start-shell
configMap:
name: reloader-start-shell
defaultMode: 0755
– name: conf-include
configMap:
name: stark-conf-include
– name: nginx-shared-confd
emptyDir: {}
– name: nginx-gitrepo
emptyDir: {}
– name: nginx-logs
emptyDir: {}
– name: time-zone
hostPath:
path: /etc/localtime
– name: data-nfs-webroot
nfs:
server: xxx.nas.aliyuncs.com
path: “/WebRoot”
– name: data-nfs-httpd
nfs:
server: xxx.nas.aliyuncs.com
path: “/httpd”
– name: data-nfs-crashdump
nfs:
server: xxx.nas.aliyuncs.com
path: “/crashdump”
– name: data-cdn
persistentVolumeClaim:
claimName: oss-pvc
如上所示,deployment的关键配置有:nodeSelector,tolerations,pod反亲和性affinity,shareProcessNamespace,资源限制(是否超卖),容器实名周期lifecycle,存活探针livenessProbe,就绪探针readinessProbe,安全上下文授权securityContext和存储挂载(NFS,OSS,emptyDir和configmap的挂载)。

6)对接阿里云SLB的service声明文件:

cat external-group01-svc.yaml

apiVersion: v1
kind: Service
metadata:
annotations:
service.beta.kubernetes.io/alibaba-cloud-loadbalancer-id: “xxx”
#service.beta.kubernetes.io/alibaba-cloud-loadbalancer-force-override-listeners: “true”
service.beta.kubernetes.io/alibaba-cloud-loadbalancer-scheduler: “wrr”
service.beta.kubernetes.io/alibaba-cloud-loadbalancer-remove-unscheduled-backend: “on”
name: external-grou01-svc
namespace: slb-nginx
spec:
externalTrafficPolicy: Local
ports:

  • port: 80
    name: http
    protocol: TCP
    targetPort: 80
  • port: 443
    name: https
    protocol: TCP
    targetPort: 443
    selector:
    app: slb-nginx-group01
    type: LoadBalancer

cat inner-group01-svc.yaml

apiVersion: v1
kind: Service
metadata:
annotations:
service.beta.kubernetes.io/alibaba-cloud-loadbalancer-id: “xxx”
service.beta.kubernetes.io/alibaba-cloud-loadbalancer-scheduler: “wrr”
service.beta.kubernetes.io/alibaba-cloud-loadbalancer-remove-unscheduled-backend: “on”
name: inner-stark-svc
namespace: slb-nginx
spec:
externalTrafficPolicy: Local
ports:

  • port: 80
    name: http
    protocol: TCP
    targetPort: 80
  • port: 443
    name: https
    protocol: TCP
    targetPort: 443
    selector:
    app: slb-nginx-group01
    type: LoadBalancer
    如上所示,对接阿里云SLB分别创建内网外的service。通过注解指定使用的负载均衡算法,指定的SLB,以及是否覆盖已有监听。externalTrafficPolicy参数指定SLB的后端列表只有部署了pod的宿主机。部署后可在阿里云SLB控制台查看负载情况。

四、监控告警
在集群中以prometheus-operator方式部署监控系统,配置监控有两种方式。分别如下:

1)第一种:创建service和ServiceMonitor来实现:
// 创建service

cat slb-nginx-exporter-svc.yaml

apiVersion: v1
kind: Service
metadata:
name: slb-nginx-exporter-svc
labels:
app: slb-nginx-exporter-svc
namespace: slb-nginx
spec:
type: ClusterIP
ports:
– name: exporter
port: 9113
targetPort: 9113
selector:
exporter: nginx // 这里的selector对应depolyment中的label

// 创建ServiceMonitor

cat nginx-exporter-serviceMonitor.yaml

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
labels:
k8s-app: nginx-exporter
name: nginx-exporter
namespace: monitoring
spec:
selector:
matchLabels:
app: slb-nginx-exporter-svc //这里的选择的label和service对应
namespaceSelector:
matchNames:
– slb-nginx
endpoints:

  • interval: 3s
    port: “exporter” //这里port的名称也需要和service对应
    scheme: http
    path: ‘/metrics’
    jobLabel: k8s-nginx-exporter

创建完这两个资源后,prometheus会自动添加生效以下配置:

kubectl -n monitoring exec -ti prometheus-k8s-0 -c prometheus — cat /etc/prometheus/config_out/prometheus.env.yaml


scrape_configs:

  • job_name: monitoring/nginx-exporter/0
    honor_labels: false
    kubernetes_sd_configs:
  • role: endpoints namespaces: names:
    • slb-nginx
      scrape_interval: 3s
      metrics_path: /metrics
      scheme: http
      relabel_configs:
  • action: keep source_labels:
    • __meta_kubernetes_service_label_app
      regex: slb-nginx-exporter-svc
  • action: keep source_labels:
    • __meta_kubernetes_endpoint_port_name
      regex: exporter
  • source_labels:
    • __meta_kubernetes_endpoint_address_target_kind
    • __meta_kubernetes_endpoint_address_target_name
      separator: ;
      regex: Node;(.*)
      replacement: ${1}
      target_label: node
  • source_labels:
    • __meta_kubernetes_endpoint_address_target_kind
    • __meta_kubernetes_endpoint_address_target_name
      separator: ;
      regex: Pod;(.*)
      replacement: ${1}
      target_label: pod
  • source_labels:
    • __meta_kubernetes_namespace
      target_label: namespace
  • source_labels:
    • __meta_kubernetes_service_name
      target_label: service
  • source_labels:
    • __meta_kubernetes_pod_name
      target_label: pod
  • source_labels:
    • __meta_kubernetes_service_name
      target_label: job
      replacement: ${1}
  • source_labels:
    • __meta_kubernetes_service_label_k8s_nginx_exporter
      target_label: job
      regex: (.+)
      replacement: ${1}
  • target_label: endpoint
    replacement: exporter

    这样,监控数据就被采集到prometheus中了。可以配置对应的告警规则了。如下:

2)第二种:直接在prometheus添加对应的配置来实现:

// 在deployment中添加如下pod的annotation
annotations:
prometheus.io/path: /metrics
prometheus.io/port: “9113”
prometheus.io/scrape: “true”

// 添加role:pods的配置,prometheus会自动去采集数据

  • job_name: ‘slb-nginx-pods’
    honor_labels: false
    kubernetes_sd_configs:
  • role: pod
    tls_config:
    insecure_skip_verify: true
    relabel_configs:
  • target_label: dc
    replacement: guangzhou
  • target_label: cluster
    replacement: guangzhou-test2
  • source_labels: [__meta_kubernetes_pod_annotation_prometheus_io_scrape] // 以下三个参数和annotation想对应
    action: keep
    regex: true
  • source_labels: [meta_kubernetes_pod_annotation_prometheus_io_path] action: replace target_label: __metrics_path
    regex: (.+)
  • source_labels: [address, meta_kubernetes_pod_annotation_prometheus_io_port] action: replace regex: ([^:]+)(?::d+)?;(d+) replacement: $1:$2 target_label: __address
  • action: labelmap
    regex: _meta_kubernetes_pod_label(.+)
  • source_labels: [__meta_kubernetes_namespace]
    action: replace
    target_label: kubernetes_namespace
  • source_labels: [__meta_kubernetes_pod_name]
    action: replace
    target_label: kubernetes_pod_name

// 添加告警规则

cat slb-nginx-pods.rules

groups:

  • name: “内网一层Nginx pods监控”
    rules:
  • alert: 内网Nginx pods 实例down
    expr: nginx_up{dc=”guangzhou”,namespace=”slb-nginx”} == 0
    for: 5s
    labels:
    severity: 0
    key: “nginx-k8s”
    annotations:
    description: “5秒钟内一层Nginx {{ $labels.instance }} 发生宕机.”
    summary: “内网k8s1.18集群{{ $labels.namespace }} 名称空间下的pod: {{ $labels.pod }} down”
    hint: “登录内网k8s1.18集群查看{{ $labels.namespace }} 名称空间下的pod: {{ $labels.pod }} 是否正常。或者联系k8s管理员进行处理。”
    测试告警如下:

五、日志收集
日志收集通过在K8S集群中部署DaemonSet实现收集每个节点上的Nginx和容器日志。这里使用Filebeat做收集,然后发送到Kafka集群,再由Logstash从Kafka中读取日志过滤后发送到ES集群。最后通过Kibana查看日志。

流程如下:

        Filebeat --> Kafka --> Logstash --> ES --> Kibana



    1)部署

Filebeat的DaemonSet部署yaml内容:

cat filebeat.yml

filebeat.inputs:

  • type: container enabled: true ignore_older: 1h paths:
    • /var/log/containers/slb-nginx-*.log
      fields:
      nodeIp: ${node_ip}
      kafkaTopic: ‘log-collect-filebeat’
      fields_under_root: true
      processors:
    • add_kubernetes_metadata:
      host: ${node_name}
      default_indexers.enabled: false
      default_matchers.enabled: false
      indexers:
      – container:
      matchers:
      – logs_path:
      logs_path: ‘/var/log/containers’
      resource_type: ‘container’
      include_annotations: [‘DISABLE_STDOUT_LOG_COLLECT’]
    • rename:
      fields:
      – from: “kubernetes.pod.ip”
      to: “containerIp”
      – from: “host.name”
      to: “nodeName”
      – from: “kubernetes.pod.name”
      to: “podName”
      ignore_missing: true
      fail_on_error: true
  • type: log
    paths:
    • “/var/lib/kubelet/pods//volumes/kubernetes.io~empty-dir/nginx-logs/access.log”
      fields:
      nodeIp: ${node_ip}
      kafkaTopic: ‘nginx-access-log-filebeat’
      topic: ‘slb-nginx-filebeat’
      fields_under_root: true

processors:

  • drop_fields:
    fields: [“ecs”, “agent”, “input”, “host”, “kubernetes”, “log”]

output.kafka:
hosts: [“kafka-svc.kafka.svc.cluster.local:9092”]
topic: ‘%{[kafkaTopic]}’
required_acks: 1
compression: gzip
max_message_bytes: 1000000

filebeat.config:
inputs:
enabled: true

# cat filebeat-ds.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
name: filebeat

namespace: kube-system

apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: filebeat
subjects:

  • kind: ServiceAccount
    name: filebeat
    namespace: kube-system
    roleRef:
    kind: ClusterRole
    name: cluster-admin

apiGroup: rbac.authorization.k8s.io

apiVersion: apps/v1
kind: DaemonSet
metadata:
generation: 1
labels:
k8s-app: slb-nginx-filebeat
name: slb-nginx-filebeat
namespace: kube-system
spec:
revisionHistoryLimit: 10
selector:
matchLabels:
k8s-app: slb-nginx-filebeat
template:
metadata:
labels:
k8s-app: slb-nginx-filebeat
spec:
nodeSelector:
app: slb-nginx-guangzhou
serviceAccount: filebeat
serviceAccountName: filebeat
containers:
– args:
– -c
– /etc/filebeat/filebeat.yml
– -e
env:
– name: node_name
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: spec.nodeName
– name: node_ip
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: status.hostIP
image: www.test.com/library/filebeat:7.6.1
imagePullPolicy: IfNotPresent
name: slb-nginx-filebeat
resources:
limits:
memory: 200Mi
requests:
cpu: 100m
memory: 100Mi
securityContext:
procMount: Default
runAsUser: 0
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
– mountPath: /etc/filebeat
name: filebeat-config
readOnly: true
– mountPath: /var/lib/kubelet/pods
name: kubeletpods
readOnly: true
– mountPath: /var/log/containers
name: containerslogs
readOnly: true
– mountPath: /var/log/pods
name: pods-logs
readOnly: true
– mountPath: /var/lib/docker/containers
name: docker-logs
readOnly: true
dnsPolicy: ClusterFirstWithHostNet
hostNetwork: true
restartPolicy: Always
volumes:
– configMap:
defaultMode: 384
name: slb-nginx-filebeat-ds-config
name: filebeat-config
– hostPath:
path: /var/lib/kubelet/pods
type: “”
name: kubeletpods
– hostPath:
path: /var/log/containers
type: “”
name: containerslogs
– hostPath:
path: /var/log/pods
type: “”
name: pods-logs
– hostPath:
path: /var/lib/docker/containers
type: “”
name: docker-logs
updateStrategy:
rollingUpdate:
maxUnavailable: 1
type: RollingUpdate

    2)查看日志:

六、测试
测试逻辑功能和pod的健壮性。发布nginx的逻辑验证;修改nginx配置文件和执行nginx -t,nginx -s reload等功能;pod杀死后自动恢复;扩缩容功能等等。如下是发布流程的日志:

可以看到,Nginx发布时,会显示更新的配置文件,并做语法检测,然后判断内存大小是否要做内存回收,最后执行reload。如果更新的不是自己分组的配置文件则不会执行reload。

总结:

最后,经过一个月的时间我们实现一层Nginx的容器化的迁移。实现了更加自动化和简便的Nginx的管理方式。同时,也更加熟悉对K8S的使用。在此分享记录,让大家对迁移传统应用到K8S等容器化平台做个参考。如果会开发,当然要拥抱Operator这样的好东西。

声明:文中观点不代表本站立场。本文传送门:https://eyangzhen.com/235133.html

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