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没有使用Helm之前,在Kubernetes部署应用,我们要依次部署deployment、service等,步骤比较繁琐。况且随着很多项目微服务化,复杂的应用在容器中部署以及管理显得较为复杂。
helm通过打包的方式,支持发布的版本管理和控制,很大程度上简化了Kubernetes应用的部署和管理。
Helm本质就是让k8s的应用管理(Deployment、Service等)可配置,能动态生成。通过动态生成K8S资源清单文件(deployment.yaml、service.yaml)。然后kubectl自动调用K8S资源部署。
Helm是官方提供类似于YUM的包管理,是部署环境的流程封装,Helm有三个重要的概念:chart、release和Repository
chart是创建一个应用的信息集合,包括各种Kubernetes对象的配置模板、参数定义、依赖关系、文档说明等。可以将chart想象成apt、yum中的软件安装包。
release是chart的运行实例,代表一个正在运行的应用。当chart被安装到Kubernetes集群,就生成一个release。chart能多次安装到同一个集群,每次安装都是一个release【根据chart赋值不同,完全可以部署出多个release出来】。
Repository用于发布和存储 Chart 的存储库。
Helm包含两个组件:Helm客户端和Tiller服务端,如下图所示:
Helm 客户端负责 chart 和 release 的创建和管理以及和 Tiller 的交互。Tiller 服务端运行在 Kubernetes 集群中,它会处理Helm客户端的请求,与 Kubernetes API Server 交互。
现在越来越多的公司和团队开始使用Helm这个Kubernetes的包管理器,我们也会使用Helm安装Kubernetes的常用组件。Helm由客户端命令helm工具和服务端tiller组成。
helm的GitHub地址
https://github.com/helm/helm
本次部署版本
服务器名称(hostname) | 系统版本 | 配置 | 内网IP | 外网IP(模拟) |
---|---|---|---|---|
k8s-master | CentOS7.7 | 2C/4G/20G | 172.16.1.110 | 10.0.0.110 |
k8s-node01 | CentOS7.7 | 2C/4G/20G | 172.16.1.111 | 10.0.0.111 |
k8s-node02 | CentOS7.7 | 2C/4G/20G | 172.16.1.112 | 10.0.0.112 |
[root@k8s-master software]# pwd
/root/software
[root@k8s-master software]# wget https://get.helm.sh/helm-v2.16.9-linux-amd64.tar.gz
[root@k8s-master software]#
[root@k8s-master software]# tar xf helm-v2.16.9-linux-amd64.tar.gz
[root@k8s-master software]# ll
total 12624
-rw-r--r-- 1 root root 12926032 Jun 16 06:55 helm-v3.2.4-linux-amd64.tar.gz
drwxr-xr-x 2 3434 3434 50 Jun 16 06:55 linux-amd64
[root@k8s-master software]#
[root@k8s-master software]# cp -a linux-amd64/helm /usr/bin/helm
因为Kubernetes API Server开启了RBAC访问控制,所以需要创建tiller的service account:tiller并分配合适的角色给它。这里为了简单起见我们直接分配cluster-admin这个集群内置的ClusterRole给它。
[root@k8s-master helm]# pwd /root/k8s_practice/helm [root@k8s-master helm]# [root@k8s-master helm]# cat rbac-helm.yaml apiVersion: v1 kind: ServiceAccount metadata: name: tiller namespace: kube-system --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: tiller roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: cluster-admin subjects: - kind: ServiceAccount name: tiller namespace: kube-system [root@k8s-master helm]# [root@k8s-master helm]# kubectl apply -f rbac-helm.yaml serviceaccount/tiller created clusterrolebinding.rbac.authorization.k8s.io/tiller created
初始化Helm的client 和 server
[root@k8s-master helm]# helm init --service-account tiller ……………… [root@k8s-master helm]# kubectl get pod -n kube-system -o wide | grep 'tiller' tiller-deploy-8488d98b4c-j8txs 0/1 Pending 0 38m <none> <none> <none> <none> [root@k8s-master helm]# ##### 之所有没有调度成功,就是因为拉取镜像包失败;查看需要拉取的镜像包 [root@k8s-master helm]# kubectl describe pod tiller-deploy-8488d98b4c-j8txs -n kube-system Name: tiller-deploy-8488d98b4c-j8txs Namespace: kube-system Priority: 0 Node: <none> Labels: app=helm name=tiller pod-template-hash=8488d98b4c Annotations: <none> Status: Pending IP: IPs: <none> Controlled By: ReplicaSet/tiller-deploy-8488d98b4c Containers: tiller: Image: gcr.io/kubernetes-helm/tiller:v2.16.9 Ports: 44134/TCP, 44135/TCP Host Ports: 0/TCP, 0/TCP Liveness: http-get http://:44135/liveness delay=1s timeout=1s period=10s #success=1 #failure=3 Readiness: http-get http://:44135/readiness delay=1s timeout=1s period=10s #success=1 #failure=3 Environment: TILLER_NAMESPACE: kube-system TILLER_HISTORY_MAX: 0 Mounts: /var/run/secrets/kubernetes.io/serviceaccount from tiller-token-kjqb7 (ro) Conditions: ………………
由上可见,镜像下载失败。原因是镜像在国外,因此这里需要修改镜像地址
[root@k8s-master helm]# helm init --upgrade --tiller-image registry.cn-beijing.aliyuncs.com/google_registry/tiller:v2.16.9
[root@k8s-master helm]#
### 等待一会儿后
[root@k8s-master helm]# kubectl get pod -o wide -A | grep 'till'
kube-system tiller-deploy-7b7787d77-zln6t 1/1 Running 0 8m43s 10.244.4.123 k8s-node01 <none> <none>
由上可见,Helm服务端tiller部署成功
helm版本信息查看
[root@k8s-master helm]# helm version
Client: &version.Version{SemVer:"v2.16.9", GitCommit:"8ad7037828e5a0fca1009dabe290130da6368e39", GitTreeState:"clean"}
Server: &version.Version{SemVer:"v2.16.9", GitCommit:"8ad7037828e5a0fca1009dabe290130da6368e39", GitTreeState:"dirty"}
helm默认使用的charts源地址
[root@k8s-master helm]# helm repo list
NAME URL
stable https://kubernetes-charts.storage.googleapis.com
local http://127.0.0.1:8879/charts
改变helm源【是否改变helm源,根据实际情况而定,一般不需要修改】
helm repo remove stable
helm repo add stable https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts
helm repo update
helm repo list
改变helm源【是否改变helm源,根据实际情况而定,一般不需要修改】
helm repo remove stable
helm repo add stable https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts
helm repo update
helm repo list
helm安装包下载存放位置
/root/.helm/cache/archive
# 列出charts仓库中所有可用的应用
helm search
# 查询指定应用
helm search memcached
# 查询指定应用的具体信息
helm inspect stable/memcached
# 用helm安装软件包,--name:指定release名字
helm install --name memcached1 stable/memcached
# 查看安装的软件包
helm list
# 删除指定引用
helm delete memcached1
chart管理
create:根据给定的name创建一个新chart
fetch:从仓库下载chart,并(可选项)将其解压缩到本地目录中
inspect:chart详情
package:打包chart目录到一个chart归档
lint:语法检测
verify:验证位于给定路径的chart已被签名且有效
release管理
get:下载一个release
delete:根据给定的release name,从Kubernetes中删除指定的release
install:安装一个chart
list:显示release列表
upgrade:升级release
rollback:回滚release到之前的一个版本
status:显示release状态信息
history:Fetch release历史信息
# 添加仓库 helm repo add REPO_INFO # 如:helm repo add incubator http://storage.googleapis.com/kubernetes-charts-incubator ##### 示例 helm repo add incubator http://storage.googleapis.com/kubernetes-charts-incubator helm repo add elastic https://helm.elastic.co # 查看helm仓库列表 helm repo list # 创建chart【可供参考,一般都是自己手动创建chart】 helm create CHART_PATH # 根据指定chart部署一个release helm install --name RELEASE_NAME CHART_PATH # 根据指定chart模拟安装一个release,并打印处debug信息 helm install --dry-run --debug --name RELEASE_NAME CHART_PATH # 列出已经部署的release helm list # 列出所有的release helm list --all # 查询指定release的状态 helm status Release_NAME # 回滚到指定版本的release,这里指定的helm release版本 helm rollback Release_NAME REVISION_NUM # 查看指定release的历史信息 helm history Release_NAME # 对指定chart打包 helm package CHART_PATH 如:helm package my-test-app/ # 对指定chart进行语法检测 helm lint CHART_PATH # 查看指定chart详情 helm inspect CHART_PATH # 从Kubernetes中删除指定release相关的资源【helm list --all 中仍然可见release记录信息】 helm delete RELEASE_NAME # 从Kubernetes中删除指定release相关的资源,并删除release记录 helm delete --purge RELEASE_NAME
[root@k8s-master helm]# pwd /root/k8s_practice/helm [root@k8s-master helm]# [root@k8s-master helm]# mkdir my-test-app [root@k8s-master helm]# cd my-test-app [root@k8s-master my-test-app]# [root@k8s-master my-test-app]# ll total 8 -rw-r--r-- 1 root root 158 Jul 16 17:53 Chart.yaml drwxr-xr-x 2 root root 49 Jul 16 21:04 templates -rw-r--r-- 1 root root 129 Jul 16 21:04 values.yaml [root@k8s-master my-test-app]# [root@k8s-master my-test-app]# cat Chart.yaml apiVersion: v1 appVersion: v2.2 description: my test app keywords: - myapp maintainers: - email: zhang@test.com name: zhang # 该name值与上级目录名相同 name: my-test-app version: v1.0.0 [root@k8s-master my-test-app]# [root@k8s-master my-test-app]# cat values.yaml deployname: my-test-app02 replicaCount: 2 images: repository: registry.cn-beijing.aliyuncs.com/google_registry/myapp tag: v2 [root@k8s-master my-test-app]# [root@k8s-master my-test-app]# ll templates/ total 8 -rw-r--r-- 1 root root 544 Jul 16 21:04 deployment.yaml -rw-r--r-- 1 root root 222 Jul 16 20:41 service.yaml [root@k8s-master my-test-app]# [root@k8s-master my-test-app]# cat templates/deployment.yaml apiVersion: apps/v1 kind: Deployment metadata: name: {{ .Values.deployname }} labels: app: mytestapp-deploy spec: replicas: {{ .Values.replicaCount }} selector: matchLabels: app: mytestapp env: test template: metadata: labels: app: mytestapp env: test description: mytest spec: containers: - name: myapp-pod image: {{ .Values.images.repository }}:{{ .Values.images.tag }} imagePullPolicy: IfNotPresent ports: - containerPort: 80 [root@k8s-master my-test-app]# [root@k8s-master my-test-app]# cat templates/service.yaml apiVersion: v1 kind: Service metadata: name: my-test-app namespace: default spec: type: NodePort selector: app: mytestapp env: test ports: - name: http port: 80 targetPort: 80 protocol: TCP
[root@k8s-master my-test-app]# pwd /root/k8s_practice/helm/my-test-app [root@k8s-master my-test-app]# ll total 8 -rw-r--r-- 1 root root 160 Jul 16 21:15 Chart.yaml drwxr-xr-x 2 root root 49 Jul 16 21:04 templates -rw-r--r-- 1 root root 129 Jul 16 21:04 values.yaml [root@k8s-master my-test-app]# [root@k8s-master my-test-app]# helm install --name mytest-app01 . ### 如果在上级目录则为 helm install --name mytest-app01 my-test-app/ NAME: mytest-app01 LAST DEPLOYED: Thu Jul 16 21:18:08 2020 NAMESPACE: default STATUS: DEPLOYED RESOURCES: ==> v1/Deployment NAME READY UP-TO-DATE AVAILABLE AGE my-test-app02 0/2 2 0 0s ==> v1/Pod(related) NAME READY STATUS RESTARTS AGE my-test-app02-58cb6b67fc-4ss4v 0/1 ContainerCreating 0 0s my-test-app02-58cb6b67fc-w2nhc 0/1 ContainerCreating 0 0s ==> v1/Service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE my-test-app NodePort 10.110.82.62 <none> 80:30965/TCP 0s [root@k8s-master my-test-app]# helm list NAME REVISION UPDATED STATUS CHART APP VERSION NAMESPACE mytest-app01 1 Thu Jul 16 21:18:08 2020 DEPLOYED my-test-app-v1.0.0 v2.2 default
[root@k8s-master ~]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES my-test-app02-58cb6b67fc-4ss4v 1/1 Running 0 9m3s 10.244.2.187 k8s-node02 <none> <none> my-test-app02-58cb6b67fc-w2nhc 1/1 Running 0 9m3s 10.244.4.134 k8s-node01 <none> <none> [root@k8s-master ~]# [root@k8s-master ~]# kubectl get svc -o wide NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 65d <none> my-test-app NodePort 10.110.82.62 <none> 80:30965/TCP 9m8s app=mytestapp,env=test [root@k8s-master ~]# ##### 根据svc的IP访问 [root@k8s-master ~]# curl 10.110.82.62 Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a> [root@k8s-master ~]# [root@k8s-master ~]# curl 10.110.82.62/hostname.html my-test-app02-58cb6b67fc-4ss4v [root@k8s-master ~]# [root@k8s-master ~]# curl 10.110.82.62/hostname.html my-test-app02-58cb6b67fc-w2nhc [root@k8s-master ~]# ##### 根据本机的IP访问 [root@k8s-master ~]# curl 172.16.1.110:30965/hostname.html my-test-app02-58cb6b67fc-w2nhc [root@k8s-master ~]# [root@k8s-master ~]# curl 172.16.1.110:30965/hostname.html my-test-app02-58cb6b67fc-4ss4v
values.yaml文件修改
[root@k8s-master my-test-app]# pwd
/root/k8s_practice/helm/my-test-app
[root@k8s-master my-test-app]#
[root@k8s-master my-test-app]# cat values.yaml
deployname: my-test-app02
replicaCount: 2
images:
repository: registry.cn-beijing.aliyuncs.com/google_registry/myapp
# 改了tag
tag: v3
重新release发布
[root@k8s-master my-test-app]# helm list NAME REVISION UPDATED STATUS CHART APP VERSION NAMESPACE mytest-app01 1 Thu Jul 16 21:18:08 2020 DEPLOYED my-test-app-v1.0.0 v2.2 default [root@k8s-master my-test-app]# [root@k8s-master my-test-app]# helm upgrade mytest-app01 . ### 如果在上级目录则为 helm upgrade mytest-app01 my-test-app/ Release "mytest-app01" has been upgraded. LAST DEPLOYED: Thu Jul 16 21:32:25 2020 NAMESPACE: default STATUS: DEPLOYED RESOURCES: ==> v1/Deployment NAME READY UP-TO-DATE AVAILABLE AGE my-test-app02 2/2 1 2 14m ==> v1/Pod(related) NAME READY STATUS RESTARTS AGE my-test-app02-58cb6b67fc-4ss4v 1/1 Running 0 14m my-test-app02-58cb6b67fc-w2nhc 1/1 Running 0 14m my-test-app02-6b84df49bb-lpww7 0/1 ContainerCreating 0 0s ==> v1/Service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE my-test-app NodePort 10.110.82.62 <none> 80:30965/TCP 14m [root@k8s-master my-test-app]# [root@k8s-master my-test-app]# helm list NAME REVISION UPDATED STATUS CHART APP VERSION NAMESPACE mytest-app01 2 Thu Jul 16 21:32:25 2020 DEPLOYED my-test-app-v1.0.0 v2.2 default
curl访问,可参见上面。可见app version已从v2改为了v3。
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