helm 部署

2018/08/14 17:25
阅读数 1.5K

Helm 基本概念

Helm 可以理解为 Kubernetes 的包管理工具,可以方便地发现、共享和使用为Kubernetes构建的应用,它包含几个基本概念

  • Chart:一个 Helm 包,其中包含了运行一个应用所需要的镜像、依赖和资源定义等,还可能包含 Kubernetes 集群中的服务定义,类似 Homebrew 中的 formula,APT 的 dpkg 或者 Yum 的 rpm 文件,
  • Release: 在 Kubernetes 集群上运行的 Chart 的一个实例。在同一个集群上,一个 Chart 可以安装很多次。每次安装都会创建一个新的 release。例如一个 MySQL Chart,如果想在服务器上运行两个数据库,就可以把这个 Chart 安装两次。每次安装都会生成自己的 Release,会有自己的 Release 名称。
  • Repository:用于发布和存储 Chart 的仓库。

Helm 组件

Helm 采用客户端/服务器架构,有如下组件组成:

  • Helm CLI 是 Helm 客户端,可以在本地执行
  • Tiller 是服务器端组件,在 Kubernetes 群集上运行,并管理 Kubernetes 应用程序的生命周期
  • Repository 是 Chart 仓库,Helm客户端通过HTTP协议来访问仓库中Chart的索引文件和压缩包。

  

安装步骤

1、 下载helm安装包

wget https://storage.googleapis.com/kubernetes-helm/helm-v2.10.0-rc.3-linux-amd64.tar.gz

2、创建tiller的serviceaccountclusterrolebinding

kubectl create serviceaccount --namespace kube-system tiller
kubectl create clusterrolebinding tiller-cluster-rule --clusterrole=cluster-admin --serviceaccount=kube-system:tiller

3. 安装helm服务端tiller

[root@master1 gateway]# helm init -i 192.168.200.10/source/kubernetes-helm/tiller:v2.10.0-rc.3  --service-account tiller --skip-refresh
Creating /root/.helm 
Creating /root/.helm/repository 
Creating /root/.helm/repository/cache 
Creating /root/.helm/repository/local 
Creating /root/.helm/plugins 
Creating /root/.helm/starters 
Creating /root/.helm/cache/archive 
Creating /root/.helm/repository/repositories.yaml 
Adding stable repo with URL: https://kubernetes-charts.storage.googleapis.com 
Adding local repo with URL: http://127.0.0.1:8879/charts 
$HELM_HOME has been configured at /root/.helm.

Tiller (the Helm server-side component) has been installed into your Kubernetes Cluster.

Please note: by default, Tiller is deployed with an insecure 'allow unauthenticated users' policy.
To prevent this, run `helm init` with the --tiller-tls-verify flag.
For more information on securing your installation see: https://docs.helm.sh/using_helm/#securing-your-helm-installation
Happy Helming!

 

4、 查看是否安装

[root@master1 gateway]# kubectl -n kube-system get pods|grep tiller
tiller-deploy-849c444cff-h9zw2 1/1 Running 0 46s

 

5. 替换helm 的repo源

[root@kubernetes-1 ~]# helm repo list
NAME    URL                                             
stable  https://kubernetes-charts.storage.googleapis.com
local   http://127.0.0.1:8879/charts 



[root@kubernetes-1 ~]# helm repo remove stable
"stable" has been removed from your repositories



[root@kubernetes-1 ~]# helm repo add stable https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts
"stable" has been added to your repositories


[root@kubernetes-1 ~]# helm repo update
Hang tight while we grab the latest from your chart repositories...
...Skip local chart repository
...Successfully got an update from the "stable" chart repository
Update Complete. ⎈ Happy Helming!⎈ 



[root@kubernetes-1 ~]# helm repo list
NAME    URL                                                   
local   http://127.0.0.1:8879/charts                          
stable  https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts

 

 

6、创建chart

helm  create    gateway

 

7. 测试修改是否正确

[root@master1 helm]# ls
gateway  helm-v2.10.0-rc.3-linux-amd64.tar.gz  linux-amd64
[root@master1 helm]# helm install --dry-run --debug ./gateway

[debug] Created tunnel using local port: '46252'

[debug] SERVER: "127.0.0.1:46252"

[debug] Original chart version: ""
[debug] CHART PATH: /root/helm/gateway

NAME:   imprecise-sabertooth
REVISION: 1
RELEASED: Tue Aug 14 14:42:14 2018
CHART: gateway-0.1.0
USER-SUPPLIED VALUES:
{}

COMPUTED VALUES:
affinity: {}
image:
  pullPolicy: IfNotPresent
  repository: 192.168.200.10/source/nginx
  tag: latest
ingress: {}
nodeSelector: {}
replicaCount: 1
resources:
  limits:
    cpu: 100m
    memory: 128Mi
  requests:
    cpu: 100m
    memory: 128Mi
service:
  port: 80
  type: ClusterIP
tolerations: []

HOOKS:
MANIFEST:

---
# Source: gateway/templates/service.yaml
apiVersion: v1
kind: Service
metadata:
  name: imprecise-sabertooth-gateway
  labels:
    app: gateway
    chart: gateway-0.1.0
    release: imprecise-sabertooth
    heritage: Tiller
spec:
  type: ClusterIP
  ports:
    - port: 80
      targetPort: http
      protocol: TCP
      name: http
  selector:
    app: gateway
    release: imprecise-sabertooth
---
# Source: gateway/templates/deployment.yaml
apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: imprecise-sabertooth-gateway
  labels:
    app: gateway
    chart: gateway-0.1.0
    release: imprecise-sabertooth
    heritage: Tiller
spec:
  replicas: 1
  selector:
    matchLabels:
      app: gateway
      release: imprecise-sabertooth
  template:
    metadata:
      labels:
        app: gateway
        release: imprecise-sabertooth
    spec:
      containers:
        - name: gateway
          image: "192.168.200.10/source/nginx:latest"
          imagePullPolicy: IfNotPresent
          ports:
            - name: http
              containerPort: 80
              protocol: TCP
          livenessProbe:
            httpGet:
              path: /
              port: http
          readinessProbe:
            httpGet:
              path: /
              port: http
          resources:
            limits:
              cpu: 100m
              memory: 128Mi
            requests:
              cpu: 100m
              memory: 128Mi

 

部署到kubernetes

[root@master1 gateway]# helm install .
NAME:   riotous-crab
LAST DEPLOYED: Tue Aug 14 14:43:21 2018
NAMESPACE: default
STATUS: DEPLOYED

RESOURCES:
==> v1/Service
NAME                  TYPE       CLUSTER-IP    EXTERNAL-IP  PORT(S)  AGE
riotous-crab-gateway  ClusterIP  10.254.26.20  <none>       80/TCP   0s

==> v1beta2/Deployment
NAME                  DESIRED  CURRENT  UP-TO-DATE  AVAILABLE  AGE
riotous-crab-gateway  1        1        1           0          0s

==> v1/Pod(related)
NAME                                  READY  STATUS             RESTARTS  AGE
riotous-crab-gateway-fd7465cc8-frcmd  0/1    ContainerCreating  0         0s


NOTES:
1. Get the application URL by running these commands:
  export POD_NAME=$(kubectl get pods --namespace default -l "app=gateway,release=riotous-crab" -o jsonpath="{.items[0].metadata.name}")
  echo "Visit http://127.0.0.1:8080 to use your application"
  kubectl port-forward $POD_NAME 8080:80

 

查看部署的relaese

helm  list

 

删除relaese

helm delete   gateway

 

将应用打包

[root@master1 gateway]# helm  package .
Successfully packaged chart and saved it to: /root/helm/gateway/gateway-0.1.0.tgz

gateway目录会被打包为一个 gateway-0.1.0.tgz 格式的压缩包,该压缩包会被放到当前目录下,并同时被保存到了 Helm 的本地缺省仓库目录中。 

如果你想看到更详细的输出,可以加上 --debug 参数来查看打包的输出,输出内容应该类似如下:

helm package gateway  --debug
Successfully packaged chart and saved it to: /root/gateway/gateway-0.1.0.tgz
[debug] Successfully saved /root/gateway/mychart-0.1.0.tgz to /root/.helm/repository/local

 

将应用发布到 Repository

虽然我们已经打包了 Chart 并发布到了 Helm 的本地目录中,但通过 helm search 命令查找,并不能找不到刚才生成的 mychart包

helm search gateway
No results found

 

这是因为 Repository 目录中的 Chart 包还没有被 Helm 管理。通过 helm repo list命令可以看到目前 Helm 中已配置的 Repository 的信息。

helm repo list
NAME    URL
stable  https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts

 

我们可以在本地启动一个 Repository Server,并将其加入到 Helm Repo 列表中。Helm Repository 必须以 Web 服务的方式提供,这里我们就使用 helm serve 命令启动一个 Repository Server,该 Server 缺省使用 $HOME/.helm/repository/local目录作为 Chart 存储,并在 8879 端口上提供服务。

chart通过HTTP server方式提供

helm serve #默认是  127.0.0.1:8879 

可以添加参数
helm serve  --address 192.168.20.171:80

如果你想使用指定目录来做为 Helm Repository 的存储目录,可以加上 --repo-path参数:

$ helm serve --address 192.168.20.171:8879 --repo-path /data/helm/repository/ --url http://192.168.20.171:8879/charts/

 

通过 helm repo index 命令将 Chart 的 Metadata 记录更新在 index.yaml 文件中:

 

# 更新 Helm Repository 的索引文件
 cd /home/k8s/.helm/repository/local
 helm repo index --url=http://192.168.20.171:8879 .

 

 完成启动本地 Helm Repository Server 后,就可以将本地 Repository 加入 Helm 的 Repo 列表。

helm repo add local http://127.0.0.1:8879
"local" has been added to your repositories

 

现在再次查找 mychart 包,就可以搜索到了。

helm repo update

helm search gateway
NAME          CHART VERSION APP VERSION DESCRIPTION
local/gateway  0.1.0         1.0         A Helm chart for Kubernetes

 

注:helm install 默认会用到 socat,需要在所有节点上安装 socat 软件包。

 

部署一个应用 通过 helm install 命令部署该 Chart

当使用 helm install 命令部署应用时,实际上就是将 templates 目录下的模板文件渲染成 Kubernetes 能够识别的 YAML 格式。

在部署前我们可以使用 helm install --dry-run --debug <chart_dir>  --name <release_name>命令来验证 Chart 的配置。该输出中包含了模板的变量配置与最终渲染的 YAML 文件。

 

[root@master1 helm]# helm install istio --name istio --namespace istio-system
Error: a release named istio already exists.
Run: helm ls --all istio; to check the status of the release
Or run: helm del --purge istio; to delete it
[root@master1 helm]# helm ls  --all istio
NAME     REVISION    UPDATED                     STATUS     CHART          APP VERSION    NAMESPACE   
istio    1           Tue Aug 14 10:48:26 2018    DELETED    istio-1.0.0    1.0.0          istio-system
[root@master1 helm]# helm ls  --all 
NAME                  REVISION    UPDATED                     STATUS     CHART               APP VERSION    NAMESPACE   
garish-lion           1           Mon Aug 13 14:22:15 2018    DELETED    gateway-0.1.2       1.2            default     
istio                 1           Tue Aug 14 10:48:26 2018    DELETED    istio-1.0.0         1.0.0          istio-system
opining-kudu          1           Mon Aug  6 17:48:14 2018    DELETED    fengjian-0.1.0      1.0            default     
riotous-crab          1           Tue Aug 14 14:43:21 2018    DELETED    gateway-0.1.0       1.0            default     
undercooked-alpaca    1           Mon Aug 13 12:13:26 2018    DELETED    gateway-0.1.0       1.0            default     
virtuous-hamster      1           Mon Aug  6 17:07:44 2018    DELETED    hello-helm-0.1.0    1.0            default     
[root@master1 helm]# helm  del --purge istio
release "istio" deleted

 

升级和回退一个应用

从上面 helm list 输出的结果中我们可以看到有一个 Revision(更改历史)字段,该字段用于表示某一个 Release 被更新的次数,我们可以用该特性对已部署的 Release 进行回滚。

修改 Chart.yaml 文件

将版本号从 0.1.0 修改为 0.2.0, 然后使用 helm package 命令打包并发布到本地仓库。

cat gateay/Chart.yaml
apiVersion: v1
appVersion: "1.0"
description: A Helm chart for Kubernetes
name: mychart
version: 0.2.0

$ helm package gateway
Successfully packaged chart and saved it to: /root/gateway/gateway-0.2.0.tgz

 

查询本地仓库中的 Chart 信息

我们可以看到在本地仓库中 gateway 有两个版本。

helm search gateway  -l
NAME          CHART VERSION APP VERSION DESCRIPTION
local/gateway 0.2.0         1.0         A Helm chart for Kubernetes
local/gateway 0.1.0         1.0         A Helm chart for Kubernetes

 

升级一个应用

现在用 helm upgrade 命令将已部署的 mike-test 升级到新版本。你可以通过 --version 参数指定需要升级的版本号,如果没有指定版本号,则缺省使用最新版本。

helm upgrade mike-test local/mychart
Release "mike-test" has been upgraded. Happy Helming!
LAST DEPLOYED: Mon Jul 23 10:50:25 2018
NAMESPACE: default
STATUS: DEPLOYED

RESOURCES:
==> v1/Pod(related)
NAME                                READY  STATUS   RESTARTS  AGE
mike-test-gateway-6d56f8c8c9-d685v  1/1    Running  0         9m

==> v1/Service
NAME               TYPE       CLUSTER-IP      EXTERNAL-IP  PORT(S)  AGE
mike-test-gateway  ClusterIP  10.254.120.177  <none>       80/TCP   9m

==> v1beta2/Deployment
NAME               DESIRED  CURRENT  UP-TO-DATE  AVAILABLE  AGE
mike-test-gateway  1        1        1           1          9m

NOTES:
1. Get the application URL by running these commands:
export POD_NAME=$(kubectl get pods --namespace default -l "app=gateway,release=mike-test" -o jsonpath="{.items[0].metadata.name}")
echo "Visit http://127.0.0.1:8080 to use your application"
kubectl port-forward $POD_NAME 8080:80

 

完成后,可以看到已部署的 mike-test 被升级到 0.2.0 版本。

helm list
NAME      REVISION  UPDATED                   STATUS    CHART         NAMESPACE
mike-test 2         Mon Jul 23 10:50:25 2018  DEPLOYED  gateway-0.2.0 default

 

回退一个应用

如果更新后的程序由于某些原因运行有问题,需要回退到旧版本的应用。首先我们可以使用 helm history 命令查看一个 Release 的所有变更记录。

helm history mike-test
REVISION  UPDATED                   STATUS      CHART         DESCRIPTION
1         Mon Jul 23 10:41:20 2018  SUPERSEDED  gateway-0.1.0 Install complete
2         Mon Jul 23 10:50:25 2018  DEPLOYED    gateway-0.2.0 Upgrade complete

 

其次,我们可以使用下面的命令对指定的应用进行回退。

helm rollback mike-test 1
Rollback was a success! Happy Helming!

 

最后,我们使用 helm list 和 helm history 命令都可以看到 mychart 的版本已经回退到 0.1.0 版本。

helm list
NAME      REVISION  UPDATED                   STATUS    CHART         NAMESPACE
mike-test 3         Mon Jul 23 10:53:42 2018  DEPLOYED  gateway-0.1.0 default

$ helm history mike-test
REVISION  UPDATED                   STATUS      CHART         DESCRIPTION
1         Mon Jul 23 10:41:20 2018  SUPERSEDED  gateway-0.1.0 Install complete
2         Mon Jul 23 10:50:25 2018  SUPERSEDED  gateway-0.2.0 Upgrade complete
3         Mon Jul 23 10:53:42 2018  DEPLOYED    gateway-0.1.0 Rollback to 1

 

删除一个应用

如果需要删除一个已部署的 Release,可以利用 helm delete 命令来完成删除。

helm delete mike-test
release "mike-test" deleted

 

确认应用是否删除,该应用已被标记为 DELETED 状态。

helm ls -a mike-test
NAME      REVISION  UPDATED                   STATUS  CHART         NAMESPACE
mike-test 3         Mon Jul 23 10:53:42 2018  DELETED gateway-0.1.0 default

 

也可以使用 --deleted 参数来列出已经删除的 Release

helm ls --deleted
NAME      REVISION  UPDATED                   STATUS  CHART         NAMESPACE
mike-test 3         Mon Jul 23 10:53:42 2018  DELETED gateway-0.1.0 default

 

从上面的结果也可以看出,默认情况下已经删除的 Release 只是将状态标识为 DELETED 了 ,但该 Release 的历史信息还是继续被保存的。

helm hist mike-test
REVISION  UPDATED                   STATUS      CHART         DESCRIPTION
1         Mon Jul 23 10:41:20 2018  SUPERSEDED  gateway-0.1.0 Install complete
2         Mon Jul 23 10:50:25 2018  SUPERSEDED  gateway-0.2.0 Upgrade complete
3         Mon Jul 23 10:53:42 2018  DELETED     gateway-0.1.0 Deletion complete

 

如果要移除指定 Release 所有相关的 Kubernetes 资源和 Release 的历史记录,可以用如下命令:

helm delete --purge mike-test
release "mike-test" deleted

 

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