Helm帮助您管理Kubernetes应用程序。在原来Kubernetes项目中都是基于yaml文件来进行部署发布微服务化应用的，会分成很多个组件来部署，每个组件可能对应一个deployment.yaml,一个service.yaml,一个Ingress.yaml等文件，还可能存在各种依赖关系。Helm旨在解决
（1）基于yaml配置的集中存放 （2）基于项目的打包 （3）组件间的依赖 （4）部署过程中的前置和后置任务 （5）更新、回滚和测试部署
Helm由以下几个组件组成：
- Helm Charts: 一个 Helm 包，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
- Helm Release: 运行中的一个Chart实例。在同一个Kubernetes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
- Helm Repository：用于发布和存储 Chart 的仓库。
- Helm Config：创建发布对象的chart的配置信息
常见的文件结构：
wordpress/
Chart.yaml # A YAML file containing information about the chart
LICENSE # OPTIONAL: A plain text file containing the license for the chart
README.md # OPTIONAL: A human-readable README file
requirements.yaml # OPTIONAL: A YAML file listing dependencies for the chart
values.yaml # The default configuration values for this chart
charts/ # A directory containing any charts upon which this chart depends.
templates/ # A directory of templates that, when combined with values,
# will generate valid Kubernetes manifest files.
templates/NOTES.txt # OPTIONAL: A plain text file containing short usage notes本节目的
- 安装配置Helm
- 使用Helm部署样例微服务
9.1 Install Helm
# 通用
curl -sSL https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3 | bash
# MacOS
brew install helm
# 验证安装
helm version --short
# 设置 stable repository
## 删除默认的源
helm repo remove stable
## 增加新的国内镜像源, 你可以选择其他偏好的国内镜像
helm repo add stable https://burdenbear.github.io/kube-charts-mirror/
helm search repo wordpress
# 配置 Bash completion
# linux
helm completion bash >> ~/.bash_completion
. /etc/profile.d/bash_completion.sh
. ~/.bash_completion
source <(helm completion bash)
# Mac
brew install bash-completion
brew tap homebrew/completions
# Edit ~/.bash_profile or ~/.bashrc
source <(kubectl completion bash)
source <(helm completion bash)
if [ -f $(brew --prefix)/etc/bash_completion ]; then
. $(brew --prefix)/etc/bash_completion
fi9.2 使用Helm部署 nginx
helm repo update
helm search repo nginx
# add nginx standalone web server
helm repo add bitnami https://charts.bitnami.com/bitnami
helm search repo bitnami/nginx
# install
helm install gcr-eks-webserver bitnami/nginx
# verify the helm chart deployed, nginx deployment available and pod on running
helm list
kubectl describe deployment gcr-eks-webserver
kubectl get pods -l app.kubernetes.io/name=nginx
# Get the NGINX URL:
#Watch the status with
kubectl get svc -n default -w gcr-eks-webserver-nginx
SERVICE_IP=$(kubectl get svc --namespace default gcr-eks-webserver-nginx --template "{{ range (index .status.loadBalancer.ingress 0) }}{{.}}{{ end }}")
echo "NGINX URL: http://${SERVICE_IP}/"
curl ${SERVICE_IP}
# cleanup
helm list
helm uninstall gcr-eks-webserver
kubectl get pods -l app.kubernetes.io/name=nginx
kubectl get svc -n default -o wide gcr-eks-webserver-nginx9.3 使用Helm部署样例微服务
学习如何用Helm部署步骤4的微服务
cd ~/temp
# create a chart
helm create eks-helm-demo
ls eks-helm-demo/
Chart.yaml charts templates values.yaml
# create our own file
rm -rf eks-helm-demo/templates/
rm eks-helm-demo/Chart.yaml
rm eks-helm-demo/values.yaml
cat <<EoF > eks-helm-demo/Chart.yaml
apiVersion: v2
name: eks-helm-demo
description: A Helm chart for EKS Workshop Microservices application
version: 0.1.0
appVersion: 1.0
EoF
#create subfolders for each template type
mkdir -p eks-helm-demo/templates/deployment
mkdir -p eks-helm-demo/templates/service
# Copy and rename frontend manifests
cp ecsdemo-frontend/kubernetes/deployment.yaml eks-helm-demo/templates/deployment/frontend.yaml
cp ecsdemo-frontend/kubernetes/service.yaml eks-helm-demo/templates/service/frontend.yaml
# Copy and rename crystal manifests
cp ecsdemo-crystal/kubernetes/deployment.yaml eks-helm-demo/templates/deployment/crystal.yaml
cp ecsdemo-crystal/kubernetes/service.yaml eks-helm-demo/templates/service/crystal.yaml
# Copy and rename nodejs manifests
cp ecsdemo-nodejs/kubernetes/deployment.yaml eks-helm-demo/templates/deployment/nodejs.yaml
cp ecsdemo-nodejs/kubernetes/service.yaml eks-helm-demo/templates/service/nodejs.yaml
# Replace hard-coded values with template directives
spec:
replicas: 1
#replace with the following:
replicas: {{ .Values.replicas }}
spec.template.spec.containers.image
#replace with
frontend.yaml - image: {{ .Values.frontend.image }}:{{ .Values.version }}
crystal.yaml - image: {{ .Values.crystal.image }}:{{ .Values.version }}
nodejs.yaml - image: {{ .Values.nodejs.image }}:{{ .Values.version }}
eks-helm-demo/templates/deployment/frontend.yaml
eks-helm-demo/templates/deployment/crystal.yaml
eks-helm-demo/templates/deployment/nodejs.yaml
cat <<EoF > eks-helm-demo/values.yaml
# Default values for eksdemo.
# This is a YAML-formatted file.
# Declare variables to be passed into your templates.
# Release-wide Values
replicas: 3
version: 'latest'
# Service Specific Values
nodejs:
image: brentley/ecsdemo-nodejs
crystal:
image: brentley/ecsdemo-crystal
frontend:
image: brentley/ecsdemo-frontend
EoF
# Deployment chart
## dry-run
helm install --debug --dry-run workshop eks-helm-demo
## install chart
helm install workshop eks-helm-demo
NAME: workshop
LAST DEPLOYED: Tue Mar 10 15:04:18 2020
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
# Verify
helm list
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
ecsdemo-crystal 3/3 3 3 11m ecsdemo-crystal brentley/ecsdemo-crystal:latest app=ecsdemo-crystal
ecsdemo-frontend 3/3 3 3 11m ecsdemo-frontend brentley/ecsdemo-frontend:latest app=ecsdemo-frontend
ecsdemo-nodejs 3/3 3 3 11m ecsdemo-nodejs brentley/ecsdemo-nodejs:latest app=ecsdemo-nodejs
kubectl get pods -l app=ecsdemo-crystal
kubectl get pods -l app=ecsdemo-nodejs
kubectl get pods -l app=ecsdemo-frontend
kubectl get svc ecsdemo-frontend -o jsonpath="{.status.loadBalancer.ingress[*].hostname}"; echo
9.4 ROLLING Upgrade / Back
# Update the demo application chart with a breaking change
# Edit values.yaml and modify the image name under nodejs.image to brentley/ecsdemo-nodejs-non-existing.
# This image does not exist, so this will break our deployment.
# rolling upgrade
helm upgrade workshop eks-helm-demo
Release "workshop" has been upgraded. Happy Helming!
NAME: workshop
LAST DEPLOYED: Tue Mar 10 15:22:20 2020
NAMESPACE: default
STATUS: deployed
REVISION: 2
TEST SUITE: None
# Check the rolling upgrade
# ecsdemo-nodejs should shown ImagePullBackOff error
kubectl get pods -l app=ecsdemo-nodejs
NAME READY STATUS RESTARTS AGE
ecsdemo-nodejs-6fdf964f5f-27569 1/1 Running 0 18m
ecsdemo-nodejs-6fdf964f5f-ngw54 1/1 Running 0 18m
ecsdemo-nodejs-6fdf964f5f-rr9m6 1/1 Running 0 18m
ecsdemo-nodejs-7c6575b56c-brfpv 0/1 ErrImagePull 0 5s
# rolling back
# Run helm status workshop to verify the LAST DEPLOYED timestamp.
helm status workshop
helm history workshop
REVISION UPDATED STATUS CHART APP VERSION DESCRIPTION
1 Tue Mar 10 15:04:18 2020 superseded eks-helm-demo-0.1.0 1 Install complete
2 Tue Mar 10 15:22:20 2020 deployed eks-helm-demo-0.1.0 1 Upgrade complete
# rollback to the 1st revision
helm rollback workshop 1
Rollback was a success! Happy Helming!
# Check status
kubectl get pods -l app=ecsdemo-nodejs
NAME READY STATUS RESTARTS AGE
ecsdemo-nodejs-6fdf964f5f-27569 1/1 Running 0 20m
ecsdemo-nodejs-6fdf964f5f-ngw54 1/1 Running 0 20m
ecsdemo-nodejs-6fdf964f5f-rr9m6 1/1 Running 0 20m
# Clean up
helm uninstall workshop
kubectl get pods -l app=ecsdemo-nodejs
kubectl get pods -l app=ecsdemo-crystal
kubectl get pods -l app=ecsdemo-frontend
kubectl get svc ecsdemo-frontend -o wide