一、简单例子

我们创建一个Chart：

# helm create hello-helm

可以看到其目录结构如下：

[root@master helm]# tree hello-helm/
hello-helm/
├── charts
├── Chart.yaml
├── templates
│   ├── deployment.yaml
│   ├── _helpers.tpl
│   ├── ingress.yaml
│   ├── NOTES.txt
│   ├── service.yaml
│   └── tests
│       └── test-connection.yaml
└── values.yaml

这是一个Nginx服务，我们修改其镜像（values.yaml）：

...
replicaCount: 1
image:
  repository: nginx
  tag: 1.7.9
  pullPolicy: IfNotPresent
...

然后安装这个Helm：

# helm install ./hello-helm/
NAME:   winning-crab
LAST DEPLOYED: Wed Nov  6 14:36:45 2019
NAMESPACE: default
STATUS: DEPLOYED
RESOURCES:
==> v1/Deployment
NAME                     READY  UP-TO-DATE  AVAILABLE  AGE
winning-crab-hello-helm  0/1    0           0          0s
==> v1/Pod(related)
NAME                                      READY  STATUS   RESTARTS  AGE
winning-crab-hello-helm-6f59ffc587-x8lrs  0/1    Pending  0         0s
==> v1/Service
NAME                     TYPE       CLUSTER-IP    EXTERNAL-IP  PORT(S)  AGE
winning-crab-hello-helm  ClusterIP  10.68.12.232  <none>       80/TCP   0s
NOTES:
1. Get the application URL by running these commands:
  export POD_NAME=$(kubectl get pods --namespace default -l "app.kubernetes.io/name=hello-helm,app.kubernetes.io/instance=winning-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

这样就安装成功了，我们可以查看其Service和Pod：

# kubectl get svc
NAME                      TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE
kubernetes                ClusterIP   10.68.0.1      <none>        443/TCP          62d
winning-crab-hello-helm   ClusterIP   10.68.12.232   <none>        80/TCP           7m5s
# kubectl get pod 
NAME                                       READY   STATUS    RESTARTS   AGE
winning-crab-hello-helm-6f59ffc587-x8lrs   1/1     Running   0          7m9s

查看release：

[root@master hello-helm]# helm list
NAME            REVISION        UPDATED                         STATUS          CHART                   APP VERSION     NAMESPACE
winning-crab    1               Wed Nov  6 14:36:45 2019        DEPLOYED        hello-helm-0.1.0        1.0             default

打包chart：

# helm package hello-helm
Successfully packaged chart and saved it to: /root/k8s/helm/hello-helm-0.1.0.tgz

然后我们就可以将打包的tgz文件分发到任意的服务器上，通过helm fetch就可以获取到该 Chart 了。

删除release：

# helm list
NAME            REVISION        UPDATED                         STATUS          CHART                   APP VERSION     NAMESPACE
winning-crab    1               Wed Nov  6 14:36:45 2019        DEPLOYED        hello-helm-0.1.0        1.0             default  
# helm delete winning-crab
release "winning-crab" deleted
# helm list
#

二、常用操作

2.1、查找chart

命令：

# helm search
# helm search mysql

2.2、查看chart详情

命令：

# helm inspect stable/mysql

2.3、安装chart

命令：

# helm install stable/mysql

如果要自定义release名字使用如下命令：

# helm install stable/mysql --name mydb

2.4、查看release状态

# helm status mydb

2.5、自定义chart

首先通过helm inspect values命令来查看可配置选项。
如下：

# helm inspect values stable/mysql
## mysql image version
## ref: https://hub.docker.com/r/library/mysql/tags/
##
image: "mysql"
imageTag: "5.7.14"
busybox:
  image: "busybox"
  tag: "1.29.3"
testFramework:
  image: "dduportal/bats"
  tag: "0.4.0"
## Specify password for root user
##
## Default: random 10 character string
# mysqlRootPassword: testing
## Create a database user
##
# mysqlUser:
## Default: random 10 character string
# mysqlPassword:
## Allow unauthenticated access, uncomment to enable
##
# mysqlAllowEmptyPassword: true
## Create a database
##
# mysqlDatabase:
## Specify an imagePullPolicy (Required)
## It's recommended to change this to 'Always' if the image tag is 'latest'
## ref: http://kubernetes.io/docs/user-guide/images/#updating-images
##
imagePullPolicy: IfNotPresent
## Additionnal arguments that are passed to the MySQL container.
## For example use --default-authentication-plugin=mysql_native_password if older clients need to
## connect to a MySQL 8 instance.
args: []
extraVolumes: |
  # - name: extras
  #   emptyDir: {}
extraVolumeMounts: |
  # - name: extras
  #   mountPath: /usr/share/extras
  #   readOnly: true
extraInitContainers: |
  # - name: do-something
  #   image: busybox
  #   command: ['do', 'something']
# Optionally specify an array of imagePullSecrets.
# Secrets must be manually created in the namespace.
# ref: https://kubernetes.io/docs/concepts/containers/images/#specifying-imagepullsecrets-on-a-pod
# imagePullSecrets:
  # - name: myRegistryKeySecretName
## Node selector
## ref: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#nodeselector
nodeSelector: {}
## Tolerations for pod assignment
## Ref: https://kubernetes.io/docs/concepts/configuration/taint-and-toleration/
##
tolerations: []
livenessProbe:
  initialDelaySeconds: 30
  periodSeconds: 10
  timeoutSeconds: 5
  successThreshold: 1
  failureThreshold: 3
readinessProbe:
  initialDelaySeconds: 5
  periodSeconds: 10
  timeoutSeconds: 1
  successThreshold: 1
  failureThreshold: 3
## Persist data to a persistent volume
persistence:
  enabled: true
  ## database data Persistent Volume Storage Class
  ## If defined, storageClassName: <storageClass>
  ## If set to "-", storageClassName: "", which disables dynamic provisioning
  ## If undefined (the default) or set to null, no storageClassName spec is
  ##   set, choosing the default provisioner.  (gp2 on AWS, standard on
  ##   GKE, AWS & OpenStack)
  ##
  # storageClass: "-"
  accessMode: ReadWriteOnce
  size: 8Gi
  annotations: {}
## Use an alternate scheduler, e.g. "stork".
## ref: https://kubernetes.io/docs/tasks/administer-cluster/configure-multiple-schedulers/
##
# schedulerName:
## Security context
securityContext:
  enabled: false
  runAsUser: 999
  fsGroup: 999
## Configure resource requests and limits
## ref: http://kubernetes.io/docs/user-guide/compute-resources/
##
resources:
  requests:
    memory: 256Mi
    cpu: 100m
# Custom mysql configuration files path
configurationFilesPath: /etc/mysql/conf.d/
# Custom mysql configuration files used to override default mysql settings
configurationFiles: {}
#  mysql.cnf: |-
#    [mysqld]
#    skip-name-resolve
#    ssl-ca=/ssl/ca.pem
#    ssl-cert=/ssl/server-cert.pem
#    ssl-key=/ssl/server-key.pem
# Custom mysql init SQL files used to initialize the database
initializationFiles: {}
#  first-db.sql: |-
#    CREATE DATABASE IF NOT EXISTS first DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_general_ci;
#  second-db.sql: |-
#    CREATE DATABASE IF NOT EXISTS second DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_general_ci;
metrics:
  enabled: false
  image: prom/mysqld-exporter
  imageTag: v0.10.0
  imagePullPolicy: IfNotPresent
  resources: {}
  annotations: {}
    # prometheus.io/scrape: "true"
    # prometheus.io/port: "9104"
  livenessProbe:
    initialDelaySeconds: 15
    timeoutSeconds: 5
  readinessProbe:
    initialDelaySeconds: 5
    timeoutSeconds: 1
  flags: []
  serviceMonitor:
    enabled: false
    additionalLabels: {}
## Configure the service
## ref: http://kubernetes.io/docs/user-guide/services/
service:
  annotations: {}
  ## Specify a service type
  ## ref: https://kubernetes.io/docs/concepts/services-networking/service/#publishing-services---service-types
  type: ClusterIP
  port: 3306
  # nodePort: 32000
  # loadBalancerIP:
ssl:
  enabled: false
  secret: mysql-ssl-certs
  certificates:
#  - name: mysql-ssl-certs
#    ca: |-
#      -----BEGIN CERTIFICATE-----
#      ...
#      -----END CERTIFICATE-----
#    cert: |-
#      -----BEGIN CERTIFICATE-----
#      ...
#      -----END CERTIFICATE-----
#    key: |-
#      -----BEGIN RSA PRIVATE KEY-----
#      ...
#      -----END RSA PRIVATE KEY-----
## Populates the 'TZ' system timezone environment variable
## ref: https://dev.mysql.com/doc/refman/5.7/en/time-zone-support.html
##
## Default: nil (mysql will use image's default timezone, normally UTC)
## Example: 'Australia/Sydney'
# timezone:
# Deployment Annotations
deploymentAnnotations: {}
# To be added to the database server pod(s)
podAnnotations: {}
podLabels: {}
## Set pod priorityClassName
# priorityClassName: {}
## Init container resources defaults
initContainer:
  resources:
    requests:
      memory: 10Mi
      cpu: 10m

然后，我们可以直接在 YAML 格式的文件中来覆盖上面的任何配置，在安装的时候直接使用该配置文件即可：(config.yaml)

mysqlUser: unclejoker
mysqlDatabase: jokerDB
service:
  type: NodePort

我们这里通过 config.yaml 文件定义了 mysqlUser 和 mysqlDatabase，并且把 service 的类型更改为了NodePort，然后现在我们来安装的时候直接指定该 yaml 文件：

# helm install -f config.yaml stable/mysql --name mydb
NAME:   mydb
LAST DEPLOYED: Wed Nov  6 15:27:01 2019
NAMESPACE: default
STATUS: DEPLOYED
RESOURCES:
==> v1/ConfigMap
NAME             DATA  AGE
mydb-mysql-test  1     1s
...

可以看到release的名字是我们定义的mydb：

# helm list
NAME    REVISION        UPDATED                         STATUS          CHART           APP VERSION     NAMESPACE
mydb    1               Wed Nov  6 15:27:01 2019        DEPLOYED        mysql-1.3.1     5.7.14          default

其service也变成了我们config.yaml中定义的nodeport：

# kubectl get svc
NAME                     TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE
kubernetes               ClusterIP   10.68.0.1      <none>        443/TCP          62d
mydb-mysql               NodePort    10.68.108.76   <none>        3306:33158/TCP   83s
[root@master helm]# kubectl get pod
NAME                                READY   STATUS    RESTARTS   AGE
mydb-mysql-8d746574b-8b2n7          0/1     Pending   0          88s

而其中pod处于pending的状态原因如下：

Events:
  Type     Reason            Age                  From               Message
  ----     ------            ----                 ----               -------
  Warning  FailedScheduling  79s (x2 over 2m43s)  default-scheduler  pod has unbound immediate PersistentVolumeClaims (repeated 2 times)

我们可以发现两个 Pod 处于 Pending 状态的原因都是 PVC 没有被绑定上，所以这里我们可以通过 storageclass 或者手动创建一个合适的 PV 对象来解决这个问题。

2.6、升级

比如我们把上面的持久化禁用掉，改写config.yaml如下：

mysqlUser: unclejoker
mysqlDatabase: jokerDB
service:
  type: NodePort
persistence:
  enabled: false

然后执行以下命令：

# helm upgrade -f config.yaml mydb stable/mysql
Release "mydb" has been upgraded.

我们可以看到Pod的状态已经变了;

# kubectl get pod
NAME                                READY   STATUS            RESTARTS   AGE
mydb-mysql-897fcbfcd-jv96j          0/1     PodInitializing   0          28s

其日志并不是PVC的问题了：

Events:
  Type    Reason     Age   From                   Message
  ----    ------     ----  ----                   -------
  Normal  Scheduled  67s   default-scheduler      Successfully assigned default/mydb-mysql-897fcbfcd-jv96j to 172.16.1.129
  Normal  Pulling    65s   kubelet, 172.16.1.129  Pulling image "busybox:1.29.3"
  Normal  Pulled     46s   kubelet, 172.16.1.129  Successfully pulled image "busybox:1.29.3"
  Normal  Created    46s   kubelet, 172.16.1.129  Created container remove-lost-found
  Normal  Started    46s   kubelet, 172.16.1.129  Started container remove-lost-found
  Normal  Pulling    45s   kubelet, 172.16.1.129  Pulling image "mysql:5.7.14"

我们可以通过helm list查看release信息：

# helm list
NAME    REVISION        UPDATED                         STATUS          CHART           APP VERSION     NAMESPACE
mydb    2               Wed Nov  6 15:33:24 2019        DEPLOYED        mysql-1.3.1     5.7.14          default

可以看到 mydb 这个 release 的REVISION已经变成2了，这是因为 release 的版本是递增的，每次安装、升级或者回滚，版本号都会加1，第一个版本号始终为1，同样我们可以使用 helm history 命令查看 release 的历史版本：

# helm history mydb
REVISION        UPDATED                         STATUS          CHART           DESCRIPTION     
1               Wed Nov  6 15:27:01 2019        SUPERSEDED      mysql-1.3.1     Install complete
2               Wed Nov  6 15:33:24 2019        DEPLOYED        mysql-1.3.1     Upgrade complete

2.7、回滚

命令如下：

# helm rollback mydb 1

2.8、删除

命令如下：

# helm delete mydb

这种删除并不会彻底删除，我们可以通过以下命令查看：

# helm list --all
NAME            REVISION        UPDATED                         STATUS  CHART                   APP VERSION     NAMESPACE
mydb            2               Wed Nov  6 15:33:24 2019        DELETED mysql-1.3.1             5.7.14          default  
winning-crab    1               Wed Nov  6 14:36:45 2019        DELETED hello-helm-0.1.0        1.0             default

如果要彻底删除需要加上—purge参数：

# helm delete mydb --purge