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TSL:20200211 Basic kubectl and Helm commands for beginners.md
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@ -1,211 +0,0 @@
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[#]: collector: (lujun9972)
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[#]: translator: (wxy)
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[#]: reviewer: ( )
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[#]: publisher: ( )
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[#]: url: ( )
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[#]: subject: (Basic kubectl and Helm commands for beginners)
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[#]: via: (https://opensource.com/article/20/2/kubectl-helm-commands)
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[#]: author: (Jessica Cherry https://opensource.com/users/jrepka)
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Basic kubectl and Helm commands for beginners
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======
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Take a trip to the grocery store to shop for the commands you'll need to
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get started with these Kubernetes tools.
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![A person working.][1]
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Recently, my husband was telling me about an upcoming job interview where he would have to run through some basic commands on a computer. He was anxious about the interview, but the best way for him to learn and remember things has always been to equate the thing he doesn't know to something very familiar to him. Because our conversation happened right after I was roaming the grocery store trying to decide what to cook that evening, it inspired me to write about kubectl and Helm commands by equating them to an ordinary trip to the grocer.
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[Helm][2] is a tool to manage applications within Kubernetes. You can easily deploy charts with your application information, allowing them to be up and preconfigured in minutes within your Kubernetes environment. When you're learning something new, it's always helpful to look at chart examples to see how they are used, so if you have time, take a look at these stable [charts][3].
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[Kubectl][4] is a command line that interfaces with Kubernetes environments, allowing you to configure and manage your cluster. It does require some configuration to work within environments, so take a look through the [documentation][5] to see what you need to do.
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I'll use namespaces in the examples, which you can learn about in my article [_Kubernetes namespaces for beginners_][6].
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Now that we have that settled, let's start shopping for basic kubectl and Helm commands!
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### Helm list
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What is the first thing you do before you go to the store? Well, if you're organized, you make a **list**. LIkewise, this is the first basic Helm command I will explain.
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In a Helm-deployed application, **list** provides details about an application's current release. In this example, I have one deployed application—the Jenkins CI/CD application. Running the basic **list** command always brings up the default namespace. Since I don't have anything deployed in the default namespace, nothing shows up:
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```
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$helm list
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NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION
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```
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However, if I run the command with an extra flag, my application and information appear:
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```
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$helm list --all-namespaces
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NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION
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jenkins jenkins 1 2020-01-18 16:18:07 EST deployed jenkins-1.9.4 lts
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```
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Finally, I can direct the **list** command to check only the namespace I want information from:
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```
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$helm list --namespace jenkins
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NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION
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jenkins jenkins 1 2020-01-18 16:18:07 EST deployed jenkins-1.9.4 lts
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```
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Now that I have a list and know what is on it, I can go and get my items with **get** commands! I'll start with the Kubernetes cluster; what can I get from it?
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### Kubectl get
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The **kubectl get** command gives information about many things in Kubernetes, including pods, nodes, and namespaces. Again, without a namespace flag, you'll always land in the default. First, I'll get the namespaces in the cluster to see what's running:
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```
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$kubectl get namespaces
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NAME STATUS AGE
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default Active 53m
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jenkins Active 44m
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kube-node-lease Active 53m
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kube-public Active 53m
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kube-system Active 53m
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```
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Now that I have the namespaces running in my environment, I'll get the nodes and see how many are running:
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```
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$kubectl get nodes
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NAME STATUS ROLES AGE VERSION
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minikube Ready master 55m v1.16.2
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```
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I have one node up and running, mainly because my Minikube is running on one small server. To get the pods running on my one node:
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```
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$kubectl get pods
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No resources found in default namespace.
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```
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Oops, it's empty. I'll get what's in my Jenkins namespace with:
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```
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$kubectl get pods --namespace jenkins
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NAME READY STATUS RESTARTS AGE
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jenkins-7fc688c874-mh7gv 1/1 Running 0 40m
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```
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Good news! There's one pod, it hasn't restarted, and it has been running for 40 minutes. Well, since I know the pod is up, I want to see what I can get from Helm.
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### Helm get
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**Helm get** is a little more complicated because this **get** command requires more than an application name, and you can request multiple things from applications. I'll begin by getting the values used to make the application, and then I'll show a snip of the **get all** action, which provides all the data related to the application.
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```
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$helm get values jenkins -n jenkins
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USER-SUPPLIED VALUES:
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null
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```
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Since I did a very minimal stable-only install, the configuration didn't change. If I run the **all** command, I get everything out of the chart:
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```
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`$helm get all jenkins -n jenkins`
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```
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![output from helm get all command][7]
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This produces a ton of data, so I always recommend keeping a copy of a Helm chart so you can look over the templates in the chart. I also create my own values to see what I have in place.
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Now that I have all my goodies in my shopping cart, I'll check the labels that **describe** what's in them. These examples pertain only to kubectl, and they describe what I've deployed through Helm.
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### Kubectl describe
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As I did with the **get** command, which can describe just about anything in Kubernetes, I'll limit my examples to namespaces, pods, and nodes. Since I know I'm working with one of each, this will be easy.
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```
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$kubectl describe ns jenkins
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Name: jenkins
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Labels: <none>
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Annotations: <none>
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Status: Active
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No resource quota.
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No resource limits.
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```
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I can see my namespace's name and that it is active and has no resource nor quote limits.
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The **describe pods** command produces a large amount of information, so I'll provide a small snip of the output. If you run the command without the pod name, it will return information for all of the pods in the namespace, which can be overwhelming. So, be sure you always include the pod name with this command. For example:
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```
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`$kubectl describe pods jenkins-7fc688c874-mh7gv --namespace jenkins`
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```
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![output of kubectl-describe-pods][8]
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This provides (among many other things) the status of the container, how the container is managed, the label, and the image used in the pod. The data not in this abbreviated output includes resource requests and limits along with any conditions, init containers, and storage volume information applied in a Helm values file. This data is useful if your application is crashing due to inadequate resources, a configured init container that runs a prescript for configuration, or generated hidden passwords that shouldn't be in a plain text YAML file.
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Finally, I'll use **describe node**, which (of course) describes the node. Since this example has just one, named Minikube, that is what I'll use; if you have multiple nodes in your environment, you must include the node name of interest.
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As with pods, the node command produces an abundance of data, so I'll include just a snip of the output.
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```
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`$kubectl describe node minikube`
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```
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![output of kubectl describe node][9]
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Note that **describe node** is one of the more important basic commands. As this image shows, the command returns statistics that indicate when the node is running out of resources, and this data is excellent for alerting you when you need to scale up (if you do not have autoscaling in your environment). Other things not in this snippet of output include the percentages of requests made for all resources and limits, as well as the age and allocation of resources (e.g., for my application).
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### Checking out
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With these commands, I've finished my shopping and gotten everything I was looking for. Hopefully, these basic commands can help you, too, in your day-to-day with Kubernetes.
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I urge you to work with the command line often and learn the shorthand flags available in the Help sections, which you can access by running these commands:
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```
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`$helm --help`
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```
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and
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```
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`$kubectl -h`
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```
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### Peanut butter and jelly
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Some things just go together like peanut butter and jelly. Helm and kubectl are a little like that.
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I often use these tools in my environment. Because they have many similarities in a ton of places, after using one, I usually need to follow up with the other. For example, I can do a Helm deployment and watch it fail using kubectl. Try them together, and see what they can do for you.
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--------------------------------------------------------------------------------
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via: https://opensource.com/article/20/2/kubectl-helm-commands
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作者：[Jessica Cherry][a]
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选题：[lujun9972][b]
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译者：[译者ID](https://github.com/译者ID)
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校对：[校对者ID](https://github.com/校对者ID)
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
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[a]: https://opensource.com/users/jrepka
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[b]: https://github.com/lujun9972
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[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/rh_003784_02_os.comcareers_os_rh2x.png?itok=jbRfXinl (A person working.)
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[2]: https://helm.sh/
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[3]: https://github.com/helm/charts/tree/master/stable
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[4]: https://kubernetes.io/docs/reference/kubectl/kubectl/
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[5]: https://kubernetes.io/docs/reference/kubectl/overview/
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[6]: https://opensource.com/article/19/12/kubernetes-namespaces
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[7]: https://opensource.com/sites/default/files/uploads/helm-get-all.png (output from helm get all command)
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[8]: https://opensource.com/sites/default/files/uploads/kubectl-describe-pods.png (output of kubectl-describe-pods)
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[9]: https://opensource.com/sites/default/files/uploads/kubectl-describe-node.png (output of kubectl describe node)
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@ -0,0 +1,198 @@
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[#]: collector: (lujun9972)
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[#]: translator: (wxy)
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[#]: reviewer: ( )
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[#]: publisher: ( )
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[#]: url: ( )
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[#]: subject: (Basic kubectl and Helm commands for beginners)
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[#]: via: (https://opensource.com/article/20/2/kubectl-helm-commands)
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[#]: author: (Jessica Cherry https://opensource.com/users/jrepka)
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适用于初学者的基本 kubectl 和 Helm 命令
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======
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> 像去杂货店购物一样，你需要用这些命令入门 Kubernetes。
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![A person working.][1]
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最近，我丈夫告诉我他即将要去参加一个工作面试，面试时他需要在计算机上运行一些基本命令。他对这场面试感到焦虑，但是对于他来说，学习和记住事情的最好方法是将不了解的事物比喻为非常熟悉的事物。因为我们的谈话是在我逛杂货店试图决定当晚要烹饪的食物之后进行的，所以这启发我用一次去杂货店的行程来描述 `kubectl` 和 `helm` 命令。
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[Helm][2]（“舵轮”）是在 Kubernetes（来自希腊语，意思是“舵手” 或 “领航员”）中管理应用程序的工具。你可以轻松地使用你的应用程序信息来部署“<ruby>海图<rt>chart</rt></ruby>”，从而可以在你的 Kubernetes 环境中几分钟之内让它们就绪并预配置好。在学习新知识时，查看示例的“海图”以了解其用法总是很有帮助的，因此，如果有时间，请查看这些稳定版的“[海图][3]”。
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[kubectl][4] 是与 Kubernetes 环境的命令行界面，允许你配置和管理集群。它需要一些配置才能在环境中工作，因此请仔细阅读其[文档][5]以了解你需要做什么。
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我将在示例中使用命名空间，你可以在我的文章《[Kubernetes 命名空间入门][6]》中了解它。
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现在我们已经准备好了，让我们开始 `kubectl`和 `helm` 基本命令的购物之旅！
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### 用 Helm 列出清单
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你去商店之前要做的第一件事是什么？好吧，如果你做事有条理，就可以创建一个“清单”。同样，这是我将解释的第一个基本的 Helm 命令。
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在一个用 Helm 部署的应用程序中，`list` 命令提供有关应用程序当前版本的详细信息。在此示例中，我有一个已部署的应用程序：Jenkins CI/CD 应用程序。运行基本的 `list` 命令总是会显示默认的命名空间。由于我没有在默认的命名空间中部署任何内容，因此不会显示任何内容：
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```
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$helm list
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NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION
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```
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但是，如果运行带有额外标志的命令，则会显示我的应用程序和信息：
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```
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$helm list --all-namespaces
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NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION
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jenkins jenkins 1 2020-01-18 16:18:07 EST deployed jenkins-1.9.4 lts
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```
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最后，我可以指示 `list` 命令只检查我想从中获取信息的命名空间：
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```
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$helm list --namespace jenkins
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NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION
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jenkins jenkins 1 2020-01-18 16:18:07 EST deployed jenkins-1.9.4 lts
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```
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现在我有了一个清单，并且知道该清单上有什么，我可以使用 `get` 命令来“获取”我的物品！我将从 Kubernetes 集群开始，我能从中获取到什么？
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### 用 Kubectl 获取物品
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`kubectl get` 命令提供有关 Kubernetes 中许多事物的信息，包括“<ruby>吊舱<rt>Pod</rt></ruby>”、节点和命名空间。同样，没有指定命名空间标志，你就会使用默认的命名空间。首先，我获取集群中的命名空间以查看正在运行的命名空间：
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```
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$kubectl get namespaces
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NAME STATUS AGE
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default Active 53m
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jenkins Active 44m
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kube-node-lease Active 53m
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kube-public Active 53m
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kube-system Active 53m
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```
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现在我已经知道了在我的环境中运行的命名空间了，接下来将获取节点并查看有多少个正在运行：
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```
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$kubectl get nodes
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NAME STATUS ROLES AGE VERSION
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minikube Ready master 55m v1.16.2
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```
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我有一个节点正在运行，这主要是因为我的 Minikube 运行在一台小型服务器上。要得到在我的这一个节点上运行的“吊舱”：
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```
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$kubectl get pods
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No resources found in default namespace.
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```
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啊哦，它是空的。我将通过以下方式获取 Jenkins 命名空间中的内容：
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```
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$kubectl get pods --namespace jenkins
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NAME READY STATUS RESTARTS AGE
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jenkins-7fc688c874-mh7gv 1/1 Running 0 40m
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```
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好消息！这里有个“吊舱”，它还没有重新启动过，已运行了 40 分钟了。好的，我知道“吊舱”已经装好，所以我想看看用 Helm 命令可以得到什么。
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### 用 Helm 获取信息
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`helm get` 稍微复杂一点，因为这个“获取”命令所需要的不仅仅是一个应用程序名称，而且你可以从应用程序中请求多个内容。我将从获取用于制作应用程序的值开始，然后展示“获取全部”的操作结果的片段，该操作将提供与该应用程序相关的所有数据。
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```
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$helm get values jenkins -n jenkins
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USER-SUPPLIED VALUES:
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null
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```
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由于我最小限度的只安装了稳定版，因此配置没有更改。如果我运行“获取全部”命令，我将得到所有“海图”：
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```
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$helm get all jenkins -n jenkins
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```
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![output from helm get all command][7]
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这会产生大量数据，因此我始终建议保留一份 Helm “海图”的副本，以便你可以查看“海图”中的模板。我还创建自己的值来了解自己所拥有的。
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现在，我把所有的商品都放在购物车中了，我会检查一下“描述”它们包含什么的标签。这些示例仅与 `kubectl` 命令有关，它们描述了我通过 Helm 部署的内容。
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### 用 kubectl 查看描述
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正如我使用“获取”命令（该命令可以描述 Kubernetes 中的几乎所有内容）所做的那样，我将示例限制定命名空间、“吊舱”和节点上。由于我知道它们每一个是什么，因此这很容易。
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```
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$kubectl describe ns jenkins
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Name: jenkins
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Labels: <none>
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Annotations: <none>
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Status: Active
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No resource quota.
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||||
No resource limits.
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```
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我可以看到我的命名空间的名称，并且它是活动的，没有资源或限额限制。
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`describe pods` 命令会产生大量信息，因此我将提供一小段输出。如果你在不使用“吊舱”名称的情况下运行该命令，它将返回名称空间中所有“吊舱”的信息，这可能会很麻烦。因此，请确保在此命令中始终包含“吊舱”名称。例如：
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||||
```
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$kubectl describe pods jenkins-7fc688c874-mh7gv --namespace jenkins
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||||
```
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||||
![output of kubectl-describe-pods][8]
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|
||||
这提供容器的状态、管理方式、标签以及“吊舱”中使用的镜像（还有很多其他信息）。不在这个简化过的输出中的数据包括资源请求和限制以及在 Helm 配置值文件中应用的任何条件、初始化容器和存储卷信息。如果你的应用程序由于资源不足而崩溃，或者是运行前置脚本进行配置的已初始化配置的容器，或者生成不应该存在于纯文本 YAML 文件中的隐藏密码，则此数据很有用。
|
||||
|
||||
最后，我将使用 `describe node` 命令，当然，它是用来描述节点的。由于本示例只有一个名为 Minikube 的示例，因此我将使用这个名字。如果你的环境中有多个节点，则必须包含你想查找的的节点名称。
|
||||
|
||||
与“吊舱”一样，这个节点的命令会产生大量数据，因此我将仅包括输出片段。
|
||||
|
||||
```
|
||||
$kubectl describe node minikube
|
||||
```
|
||||
|
||||
![output of kubectl describe node][9]
|
||||
|
||||
注意，`describe node` 是更重要的基本命令之一。如此图所示，该命令返回统计信息，该信息指示节点何时资源用尽，并且该数据非常适合在需要扩展时（如果你的环境中没有自动扩展）向你发出警报。此输出片段中未包含的其他内容包括对所有资源和限制的请求所占的百分比，以及资源的使用期限和分配（例如，对于我的应用程序而言）。
|
||||
|
||||
### 买单
|
||||
|
||||
使用这些命令，我完成了购物并得到了我想要的一切。希望这些基本命令也能在你使用 Kubernetes 的日常工作中提供帮助。
|
||||
|
||||
我鼓励你经常使用命令行并学习“帮助”部分中的速记标志，你可以通过运行以下命令来查看这些标志：
|
||||
|
||||
```
|
||||
$helm --help
|
||||
```
|
||||
|
||||
或
|
||||
|
||||
```
|
||||
$kubectl -h
|
||||
```
|
||||
|
||||
### 花生酱和果冻
|
||||
|
||||
有些东西像花生酱和果冻一样混在一起。Helm 和 `kubectl` 就有点像那样。
|
||||
|
||||
我经常在自己的环境中使用这些工具。因为它们在很多地方都有很多相似之处，所以在使用其中一个之后，我通常需要跟进另一个。例如，我可以进行 Helm 部署，并使用 `kubectl` 观察它是否失败。一起试试它们，看看它们能为你做什么。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/20/2/kubectl-helm-commands
|
||||
|
||||
作者：[Jessica Cherry][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[wxy](https://github.com/wxy)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]: https://opensource.com/users/jrepka
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/rh_003784_02_os.comcareers_os_rh2x.png?itok=jbRfXinl (A person working.)
|
||||
[2]: https://helm.sh/
|
||||
[3]: https://github.com/helm/charts/tree/master/stable
|
||||
[4]: https://kubernetes.io/docs/reference/kubectl/kubectl/
|
||||
[5]: https://kubernetes.io/docs/reference/kubectl/overview/
|
||||
[6]: https://linux.cn/article-11749-1.html
|
||||
[7]: https://opensource.com/sites/default/files/uploads/helm-get-all.png (output from helm get all command)
|
||||
[8]: https://opensource.com/sites/default/files/uploads/kubectl-describe-pods.png (output of kubectl-describe-pods)
|
||||
[9]: https://opensource.com/sites/default/files/uploads/kubectl-describe-node.png (output of kubectl describe node)
|
||||
Loading…
Reference in New Issue
Block a user