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Xingyu.Wang
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commit
bb69580a1b
@ -1,203 +0,0 @@
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[#]: collector: (lujun9972)
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[#]: translator: (HankChow)
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[#]: reviewer: ( )
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[#]: publisher: ( )
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[#]: url: ( )
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[#]: subject: (Run Kubernetes on a Raspberry Pi with k3s)
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[#]: via: (https://opensource.com/article/20/3/kubernetes-raspberry-pi-k3s)
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[#]: author: (Lee Carpenter https://opensource.com/users/carpie)
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Run Kubernetes on a Raspberry Pi with k3s
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======
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Create your own three-node Kubernetes cluster with these easy-to-follow
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instructions.
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![A ship wheel with someone steering][1]
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For a long time, I've been interested in building a [Kubernetes][2] cluster out of a stack of inexpensive Raspberry Pis. Following along with various tutorials on the web, I was able to get Kubernetes installed and working in a three Pi cluster. However, the RAM and CPU requirements on the master node overwhelmed my Pi. This caused poor performance when doing various Kubernetes tasks. It also made an in-place upgrade of Kubernetes impossible.
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As a result, I was very excited to see the [k3s project][3]. K3s is billed as a lightweight Kubernetes for use in resource-constrained environments. It is also optimized for ARM processors. This makes running a Raspberry Pi-based Kubernetes cluster much more feasible. In fact, we are going to create one in this article.
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### Materials needed
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To create the Kubernetes cluster described in this article, we are going to need:
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* At least one Raspberry Pi (with SD card and power adapter)
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* Ethernet cables
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* A switch or router to connect all our Pis together
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We will be installing k3s from the internet, so they will need to be able to access the internet through the router.
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### An overview of our cluster
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For this cluster, we are going to use three Raspberry Pis. The first we'll name **kmaster** and assign a static IP of 192.168.0.50 (since our local network is 192.168.0.0/24). The first worker node (the second Pi), we'll name **knode1** and assign an IP of 192.168.0.51. The final worker node we'll name **knode2** and assign an IP of 192.168.0.52.
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Obviously, if you have a different network layout, you may use any network/IPs you have available. Just substitute your own values anywhere IPs are used in this article.
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So that we don't have to keep referring to each node by IP, let's add their host names to our **/etc/hosts** file on our PC.
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```
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echo -e "192.168.0.50\tkmaster" | sudo tee -a /etc/hosts
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echo -e "192.168.0.51\tknode1" | sudo tee -a /etc/hosts
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echo -e "192.168.0.52\tknode2" | sudo tee -a /etc/hosts
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```
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### Installing the master node
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Now we're ready to install the master node. The first step is to install the latest Raspbian image. I am not going to explain that here, but I have a [detailed article][4] on how to do this if you need it. So please go install Raspbian, enable the SSH server, set the hostname to **kmaster**, and assign a static IP of 192.168.0.50.
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Now that Raspbian is installed on the master node, let's boot our master Pi and **ssh** into it:
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```
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`ssh pi@kmaster`
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```
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Now we're ready to install **k3s**. On the master Pi, run:
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```
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`curl -sfL https://get.k3s.io | sh -`
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```
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When the command finishes, we already have a single node cluster set up and running! Let's check it out. Still on the Pi, run:
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```
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`sudo kubectl get nodes`
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```
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You should see something similar to:
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```
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NAME STATUS ROLES AGE VERSION
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kmaster Ready master 2m13s v1.14.3-k3s.1
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```
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### Extracting the join token
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We want to add a couple of worker nodes. When installing **k3s** on those nodes we will need a join token. The join token exists on the master node's filesystem. Let's copy that and save it somewhere we can get to it later:
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```
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`sudo cat /var/lib/rancher/k3s/server/node-token`
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```
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### Installing the worker nodes
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Grab some SD cards for the two worker nodes and install Raspbian on each. For one, set the hostname to **knode1** and assign an IP of 192.168.0.51. For the other, set the hostname to **knode2** and assign an IP of 192.168.0.52. Now, let's install **k3s**.
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Boot your first worker node and **ssh** into it:
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```
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`ssh pi@knode1`
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```
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On the Pi, we'll install **k3s** as before, but we will give the installer extra parameters to let it know that we are installing a worker node and that we'd like to join the existing cluster:
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```
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curl -sfL <http://get.k3s.io> | K3S_URL=<https://192.168.0.50:6443> \
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K3S_TOKEN=join_token_we_copied_earlier sh -
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```
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Replace **join_token_we_copied_earlier** with the token from the "Extracting the join token" section. Repeat these steps for **knode2**.
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### Access the cluster from our PC
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It'd be annoying to have to **ssh** to the master node to run **kubectl** anytime we wanted to inspect or modify our cluster. So, we want to put **kubectl** on our PC. But first, let's get the configuration information we need from our master node. **Ssh** into **kmaster** and run:
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```
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`sudo cat /etc/rancher/k3s/k3s.yaml`
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```
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Copy this configuration information and return to your PC. Make a directory for the config:
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```
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`mkdir ~/.kube`
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```
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Save the copied configuration as **~/.kube/config**. Now edit the file and change the line:
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```
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`server: https://localhost:6443`
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```
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to be:
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```
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`server: https://kmaster:6443`
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```
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For security purpose, limit the file's read/write permissions to just yourself:
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```
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`chmod 600 ~/.kube/config`
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```
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Now let's install **kubectl** on our PC (if you don't already have it). The Kubernetes site has [instructions][5] for doing this for various platforms. Since I'm running Linux Mint, an Ubuntu derivative, I'll show the Ubuntu instructions here:
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```
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sudo apt update && sudo apt install -y apt-transport-https
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curl -s <https://packages.cloud.google.com/apt/doc/apt-key.gpg> | sudo apt-key add -
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echo "deb <https://apt.kubernetes.io/> kubernetes-xenial main" | \
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sudo tee -a /etc/apt/sources.list.d/kubernetes.list
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sudo apt update && sudo apt install kubectl
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```
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If you're not familiar, the above commands add a Debian repository for Kubernetes, grab its GPG key for security, and then update the list of packages and install **kubectl**. Now, we'll get notifications of any updates for **kubectl** through the standard software update mechanism.
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Now we can check out our cluster from our PC! Run:
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```
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`kubectl get nodes`
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```
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You should see something like:
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```
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NAME STATUS ROLES AGE VERSION
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kmaster Ready master 12m v1.14.3-k3s.1
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knode1 Ready worker 103s v1.14.3-k3s.1
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knode1 Ready worker 103s v1.14.3-k3s.1
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```
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Congratulations! You have a working 3-node Kubernetes cluster!
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### The k3s bonus
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If you run **kubectl get pods --all-namespaces**, you will see some extra pods for [Traefik][6]. Traefik is a reverse proxy and load balancer that we can use to direct traffic into our cluster from a single entry point. Kubernetes allows for this but doesn't provide such a service directly. Having Traefik installed by default is a nice touch by Rancher Labs. This makes a default **k3s** install fully complete and immediately usable!
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We're going to explore using Traefik through Kubernetes **ingress** rules and deploy all kinds of goodies to our cluster in future articles. Stay tuned!
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--------------------------------------------------------------------------------
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via: https://opensource.com/article/20/3/kubernetes-raspberry-pi-k3s
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作者：[Lee Carpenter][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/carpie
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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/ship_wheel_gear_devops_kubernetes.png?itok=xm4a74Kv (A ship wheel with someone steering)
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[2]: https://opensource.com/resources/what-is-kubernetes
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[3]: https://k3s.io/
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[4]: https://carpie.net/articles/headless-pi-with-static-ip-wired-edition
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[5]: https://kubernetes.io/docs/tasks/tools/install-kubectl/
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[6]: https://traefik.io/
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@ -0,0 +1,202 @@
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[#]: collector: (lujun9972)
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||||
[#]: translator: (HankChow)
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||||
[#]: reviewer: ( )
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||||
[#]: publisher: ( )
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||||
[#]: url: ( )
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[#]: subject: (Run Kubernetes on a Raspberry Pi with k3s)
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[#]: via: (https://opensource.com/article/20/3/kubernetes-raspberry-pi-k3s)
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[#]: author: (Lee Carpenter https://opensource.com/users/carpie)
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使用 K3s 在树莓派上运行 Kubernetes 集群
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======
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> 跟随接下来的介绍，自己搭建一个三节点的 Kubernetes 集群。
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![A ship wheel with someone steering][1]
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我对在树莓派上搭建 [Kubernetes][2] 集群已经感兴趣很长时间了，只要照着网上的教程，我可以在由三个树莓派组成的集群中搭建一套 Kubernetes 并正常运行。但在这种情况下，主节点上的内存和 CPU 资源捉襟见肘，执行 Kubernetes 任务的时候往往性能不佳，想要升级 Kubernetes 就更不可能了。
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这个时候，我发现了 [K3s][3] 这个项目。K3s 誉为可用于资源受限环境下的轻量级 Kubernetes，它还针对 ARM 处理器做出了优化，这让 Kubernetes 集群可以在树莓派上运行得更好。在下文中，我们将会使用 K3s 来创建一个 Kubernetes 集群。
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### 准备
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要按照本文介绍的方式创建 Kubernetes 集群，首先需要准备：
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* 至少一个树莓派（包括 SD 卡和电源）
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* 网线
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* 将所有树莓派连接到一起的交换机或路由器
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我们会通过在线安装的方式安装 K3s，因此还需要可以连接到互联网。
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### 集群概览
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在这个集群里，我们会使用三个树莓派。其中一个树莓派作为主节点，我们将它命名为 `kmaster`，并为其分配一个静态 IP `192.168.0.50`（注：假设使用的私有网段是 192.168.0.0/24），而另外两个树莓派作为工作节点，分别命名为 `knode1` 和 `knode2`，也分别分配 `192.168.0.51` 和 `192.168.0.52` 两个 IP 地址。
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当然，如果你实际的网络布局和上面不同，只要将文中所提及到的 IP 替换成你实际可用的 IP 就可以了。
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为了不需要通过 IP 来引用某一个节点，我们将每个节点的主机名记录到 PC 的 `/etc/hosts` 文件当中：
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```
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echo -e "192.168.0.50\tkmaster" | sudo tee -a /etc/hosts
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echo -e "192.168.0.51\tknode1" | sudo tee -a /etc/hosts
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echo -e "192.168.0.52\tknode2" | sudo tee -a /etc/hosts
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```
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### 部署主节点
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我们首先部署主节点。最开始的步骤当然是使用镜像安装最新的 Raspbian，这个步骤可以参考我的[另一篇文章][4]，在这里就不展开介绍了。在安装完成之后，启动 SSH 服务，将主机名设置为 `kmaster`，然后分配静态 IP `192.168.0.50`。
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在主节点上安装 Raspbian 完成后，启动树莓派并通过 `ssh` 连接上去：
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```
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ssh pi@kmaster
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```
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执行以下命令安装 K3s：
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```
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curl -sfL https://get.k3s.io | sh -
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```
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等到命令跑完以后，一个单节点集群就已经运行起来了。还在这个树莓派上执行：
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```
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sudo kubectl get nodes
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```
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就会看到这样的输出：
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```
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NAME STATUS ROLES AGE VERSION
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kmaster Ready master 2m13s v1.14.3-k3s.1
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```
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### 获取<ruby>连接令牌<rt>join token</rt></ruby>
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之后我们需要部署工作节点。在工作节点上安装 K3s 的时候，会需要用到连接令牌，它放置在主节点的文件系统上。首先把连接令牌打印出来保存以便后续使用：
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```
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sudo cat /var/lib/rancher/k3s/server/node-token
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```
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### 部署工作节点
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通过 SD 卡在每个作为工作节点的树莓派上安装 Raspbian。在这里，我们把其中一个树莓派的主机名设置为 `knode1`，为其分配 IP 地址 `192.168.0.51`，另一个树莓派的主机名设置为 `knode2`，分配 IP 地址 `192.168.0.52`。接下来就可以安装 K3s 了。
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启动主机名为 `knode1` 的树莓派，通过 `ssh` 连接上去：
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```
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ssh pi@knode1
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```
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在这个树莓派上，安装 K3s 的过程和之前差不多，但需要另外加上一些参数，表示它是一个工作节点，需要连接到一个已有的集群上：
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```
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curl -sfL <http://get.k3s.io> | K3S_URL=<https://192.168.0.50:6443> \
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K3S_TOKEN=<刚才保存下来的连接令牌> sh -
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```
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`K3S_TOKEN` 的值需要替换成刚才保存下来的实际的连接令牌。完成之后，在主机名为 `knode2` 的树莓派上重复这个安装过程。
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### 通过 PC 访问集群
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现在如果我们想要查看或者更改集群，都必须 `ssh` 到集群的主节点才能使用 `kubectl`，这是比较麻烦的。因此我们会将 `kubectl` 放到 PC 上使用。首先，在主节点上获取一些必要的配置信息，`ssh` 到 `kmaster` 上执行：
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```
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sudo cat /etc/rancher/k3s/k3s.yaml
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```
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复制上面命令的输出，创建一个目录用来放置配置文件：
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```
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mkdir ~/.kube
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```
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将复制好的内容写入到 `~/.kube/config` 文件中，然后将
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|
||||
```
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||||
server: https://localhost:6443
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||||
```
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||||
|
||||
改为
|
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||||
|
||||
```
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||||
server: https://kmaster:6443
|
||||
```
|
||||
|
||||
出于安全考虑，只对自己保留这个配置文件的读写权限：
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||||
|
||||
|
||||
```
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||||
chmod 600 ~/.kube/config
|
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```
|
||||
|
||||
如果 PC 上还没有安装 `kubectl` 的话，就可以开始安装了。Kubernetes 官方网站上有各种平台安装 `kubectl` 的[方法说明][5]，我使用的是 Ubuntu 的衍生版 Linux Mint，所以我的安装方法是这样的：
|
||||
|
||||
|
||||
```
|
||||
sudo apt update && sudo apt install -y apt-transport-https
|
||||
curl -s <https://packages.cloud.google.com/apt/doc/apt-key.gpg> | sudo apt-key add -
|
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echo "deb <https://apt.kubernetes.io/> kubernetes-xenial main" | \
|
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sudo tee -a /etc/apt/sources.list.d/kubernetes.list
|
||||
sudo apt update && sudo apt install kubectl
|
||||
```
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||||
|
||||
上面几个命令的作用是添加了一个包含 Kubernetes 的 Debian 软件库，获取 GPG 密钥以确保安全，然后更新软件包列表并安装 `kubectl`。如果 `kubectl` 有更新，我们将会通过<ruby>标准软件更新机制<rt>standard software update mechanism</rt></ruby>收到通知。
|
||||
|
||||
现在在 PC 上就可以查看 Kubernetes 集群了：
|
||||
|
||||
|
||||
```
|
||||
kubectl get nodes
|
||||
```
|
||||
|
||||
输出大概会是这样：
|
||||
|
||||
|
||||
```
|
||||
NAME STATUS ROLES AGE VERSION
|
||||
kmaster Ready master 12m v1.14.3-k3s.1
|
||||
knode1 Ready worker 103s v1.14.3-k3s.1
|
||||
knode1 Ready worker 103s v1.14.3-k3s.1
|
||||
```
|
||||
|
||||
至此，我们已经搭建了一个三节点的 Kubernetes 集群。
|
||||
|
||||
### K3s 的彩蛋
|
||||
|
||||
如果执行 `kubectl get pods --all-namespaces`，就会看到其它服务的一些 pod，比如 [Traefik][6]。Traefik 在这里起到是反向代理和负载均衡器的作用，它可以让流量从单个入口进入集群后引导到集群中的各个服务。Kubernetes 支持这种机制，但 Kubernetes 本身不提供这个功能，因此 Traefik 是一个不错的选择，K3s 安装后立即可用的优点也得益于此。
|
||||
|
||||
在后续的文章中，我们会继续探讨 Traefik 在 Kubernetes ingress 中的应用，以及在集群中部署其它组件。敬请关注。
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/20/3/kubernetes-raspberry-pi-k3s
|
||||
|
||||
作者：[Lee Carpenter][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[HankChow](https://github.com/HankChow)
|
||||
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/carpie
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/ship_wheel_gear_devops_kubernetes.png?itok=xm4a74Kv (A ship wheel with someone steering)
|
||||
[2]: https://opensource.com/resources/what-is-kubernetes
|
||||
[3]: https://k3s.io/
|
||||
[4]: https://carpie.net/articles/headless-pi-with-static-ip-wired-edition
|
||||
[5]: https://kubernetes.io/docs/tasks/tools/install-kubectl/
|
||||
[6]: https://traefik.io/
|
||||
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Reference in New Issue
Block a user