K3s是由Rancher Labs于今年年初发布的一款开源、极轻量的Kubernetes发行版，完美适用于在资源有限的环境中运行Kubernetes。K3s一经发布就得到了业界的高度关注和认可，发布半年以来已在GitHub上拥有近8500颗Star。

最初k3s只是一个用于本地Kubernetes开发的POC项目，而如今已有很多企业用户在生产环境中使用它。

官方GitRepo:

https://github.com/rancher/k3s

官方定义：k3s是完全符合标准的生产级Kubernetes发行版，具有以下四个方面的主要变化：

• 删除旧的、非必须的代码：K3s不包括任何默认禁用的Alpha功能或者过时的功能，原有的API组件目前仍运行于标准部署当中。除此之外，Rancher还删除了所有非默认许可控制器，in- tree云提供商和存储驱动程序，但允许用户添加任何他们需要的驱动程序。
• 整合正在运行的打包进程：为了节省RAM，Rancher将通常在Kubernetes管理服务器上运行的多流程合并为单个流程。Rancher还将在工作节点上运行的kubelet、kubeproxy和flannel代理进程组合成一个进程。
• 使用containerd代替Docker作为运行时的容器引擎：通过用containderd替换Docker，Rancher能够显著减少运行时占用空间，删除libnetwork、swarm、Docker存储驱动程序和其他插件等功能。
• 除了 etcd 之外，引入 SQLite 作为可选的数据存储：Rancher在k3s中添加了SQLite作为可选的数据存储，从而为etcd提供了一个轻量级的替代方案。该方案不仅占用了较少的内存，而且大幅简化了操作。

鉴于k3s受到极高的关注度以及广泛的应用，大量的开源社区用户开始搭建有关k3s的项目，本文将分享如何使用其中一个项目——k3sup，来实现一分钟内从零到完全配置k3s Kubeconfig。

K3sup：1分钟之内，从零到完全配置Kubeconfig

K3sup：https://github.com/alexellis/k3sup

K3sup是由Alex Ellis创建的一个开源项目，这使得k3s的安装和kubeconfig文件的生成变得快速和方便。这一工具能以极快的速度自动化安装k3s、将SAN地址更新为公共IP、下载k3s配置文件然后使用VM的公共IP地址将其更新，以便可以使用kubectl连接它。

以下步骤使用Amazon EC2实例说明了此过程：

步骤1：启动Amazon EC2实例，让安全组打开端口并通过ssh登录。

• 登录亚马逊控制台并单击EC2
• 在EC2 Dashboard上，点击启动实例
• 选择 Amazon Linux 2 AMI 镜像
• 选择实例类型(我们将使用t2.medium)
• 选择VPC/Subnet/IAM等并且启用自动分配公共IP(一切都保持默认)
• 添加存储(使用默认配置)
• 添加标签(如果需要的话)
• 配置安全组以允许不同端口上的流量(本demo中启用所有流量)
• 选择一个密钥对并且启动实例

步骤2：下载k3sup的二进制文件

curl -sLS https://raw.githubusercontent.com/alexellis/k3sup/master/get.sh | sh[root@ip-172-31-33-136 ec2-user]# curl -sLS https://raw.githubusercontent.com/alexellis/k3sup/master/get.sh | shwhich: no k3sup in (/sbin:/bin:/usr/sbin:/usr/bin)x86_64Downloading package https://github.com/alexellis/k3sup/releases/download/0.2.0/k3sup as /tmp/k3supDownload complete.Running as root - Attempting to move k3sup to /usr/local/binNew version of k3sup installed to /usr/local/bin

步骤3：将ssh密钥复制到VM中的'vi /root/.ssh/id_rsa'位置，导出IP并使用k3sup安装k3s

[root@ip-172-31-33-136 ec2-user]# **cd /usr/local/bin**[root@ip-172-31-33-136 bin]# **export IP=54.159.112.255**[root@ip-172-31-33-136 bin]# **./k3sup install --ip $IP --user ec2-user**Public IP: 54.159.112.255ssh -i /root/.ssh/id_rsa ec2-user@54.159.112.255ssh: curl -sLS https://get.k3s.io | INSTALL_K3S_EXEC='server --tls-san 54.159.112.255' sh -[INFO] Finding latest release[INFO] Using v0.8.0 as release[INFO] Downloading hash [https://github.com/rancher/k3s/releases/download/v0.8.0/sha256sum-amd64.txt](https://github.com/rancher/k3s/releases/download/v0.8.0/sha256sum-amd64.txt)[INFO] Downloading binary [https://github.com/rancher/k3s/releases/download/v0.8.0/k3s](https://github.com/rancher/k3s/releases/download/v0.8.0/k3s)[INFO] Verifying binary download[INFO] Installing k3s to /usr/local/bin/k3swhich: no kubectl in (/usr/local/bin:/usr/bin)[INFO] Creating /usr/local/bin/kubectl symlink to k3swhich: no crictl in (/usr/local/bin:/usr/bin)[INFO] Creating /usr/local/bin/crictl symlink to k3swhich: no ctr in (/usr/local/bin:/usr/bin)[INFO] Creating /usr/local/bin/ctr symlink to k3s[INFO] Creating killall script /usr/local/bin/k3s-killall.sh[INFO] Creating uninstall script /usr/local/bin/k3s-uninstall.sh[INFO] env: Creating environment file /etc/systemd/system/k3s.service.env[INFO] systemd: Creating service file /etc/systemd/system/k3s.service[INFO] systemd: Enabling k3s unitCreated symlink from /etc/systemd/system/multi-user.target.wants/k3s.service to /etc/systemd/system/k3s.service.[INFO] systemd: Starting k3sResult: [INFO] Finding latest release[INFO] Using v0.8.0 as release[INFO] Downloading hash [https://github.com/rancher/k3s/releases/download/v0.8.0/sha256sum-amd64.txt](https://github.com/rancher/k3s/releases/download/v0.8.0/sha256sum-amd64.txt)[INFO] Downloading binary [https://github.com/rancher/k3s/releases/download/v0.8.0/k3s](https://github.com/rancher/k3s/releases/download/v0.8.0/k3s)[INFO] Verifying binary download[INFO] Installing k3s to /usr/local/bin/k3s[INFO] Creating /usr/local/bin/kubectl symlink to k3s[INFO] Creating /usr/local/bin/crictl symlink to k3s[INFO] Creating /usr/local/bin/ctr symlink to k3s[INFO] Creating killall script /usr/local/bin/k3s-killall.sh[INFO] Creating uninstall script /usr/local/bin/k3s-uninstall.sh[INFO] env: Creating environment file /etc/systemd/system/k3s.service.env[INFO] systemd: Creating service file /etc/systemd/system/k3s.service[INFO] systemd: Enabling k3s unit[INFO] systemd: Starting k3swhich: no kubectl in (/usr/local/bin:/usr/bin)which: no crictl in (/usr/local/bin:/usr/bin)which: no ctr in (/usr/local/bin:/usr/bin)Created symlink from /etc/systemd/system/multi-user.target.wants/k3s.service to /etc/systemd/system/k3s.service.ssh: sudo cat /etc/rancher/k3s/k3s.yamlSaving file to: /usr/local/bin/kubeconfig

它将创建一个kubeconfig文件并且保存在你运行命令的目录中。

步骤4：导出KUBECONFIG

[root@ip-172-31-33-136 bin]#** export KUBECONFIG=`pwd`/kubeconfig**

步骤5：开始玩转k3s

[root@ip-172-31-33-136 bin]# **./kubectl get nodes**NAME STATUS ROLES AGE VERSIONip-172-31-33-136.ec2.internal Ready master 24s v1.14.5-k3s.1[root@ip-172-31-33-136 bin]# **./kubectl get pods -n kube-system**NAME READY STATUS RESTARTS AGEcoredns-b7464766c-ngf46 1/1 Running 0 4m3shelm-install-traefik-x6wfj 0/1 Completed 0 4m3ssvclb-traefik-65gw9 2/2 Running 0 3m49straefik-56688c4464-5rdss 1/1 Running 0 3m49s

运行一个简单的服务：

# Create a Deployment**./kubectl run nginx --image=nginx**# Create Service[root@ip-172-31-33-136 bin]# **./kubectl expose deployment nginx --port=80 --target-port=80**service/nginx exposed[root@ip-172-31-33-136 bin]# **./kubectl get svc**NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGEkubernetes ClusterIP 10.43.0.1  443/TCP 45mnginx ClusterIP 10.43.99.179  80/TCP 5s[root@ip-172-31-33-136 bin]# **curl 10.43.99.179**Welcome to nginx!

Welcome to nginx!

If you see this page, the nginx web server is successfully installed andworking. Further configuration is required.

For online documentation and support please refer tonginx.org.
Commercial support is available atnginx.com.

Thank you for using nginx.

加入两个节点：是否可以在不登录节点的情况下将节点与主节点连接？是的，k3sup可以做到这一点。

在VM上获得k3s设置后，你可以轻松地将节点加入到集群：

#AGENT_IP is the IP of the VM that you want to add to the cluster that has k3s running**export AGENT_IP=54.196.113.156**#SERVER_IP is the IP of the server where k3 is installed export SERVER_IP=54.159.112.255**export USER=ec2-user**[root@ip-172-31-33-136 bin]# **./k3sup join --ip $AGENT_IP --server-ip $SERVER_IP --user ec2-user**Server IP: 54.159.112.255ssh -i /root/.ssh/id_rsa ec2-user@54.159.112.255ssh: sudo cat /var/lib/rancher/k3s/server/node-tokenK1077d707d0868b652aca7adfc21b5f34a1f0357e71b216bf8b3c94a559cd4f93a6::node:014c8ed3f6574d27db73b9c8bf67f617ssh: curl -sfL https://get.k3s.io/ | K3S_URL="https://54.159.112.255:6443" K3S_TOKEN="K1077d707d0868b652aca7adfc21b5f34a1f0357e71b216bf8b3c94a559cd4f93a6::node:014c8ed3f6574d27db73b9c8bf67f617" sh -[INFO] Finding latest release[INFO] Using v0.8.0 as release[INFO] Downloading hash [https://github.com/rancher/k3s/releases/download/v0.8.0/sha256sum-amd64.txt](https://github.com/rancher/k3s/releases/download/v0.8.0/sha256sum-amd64.txt)[INFO] Downloading binary [https://github.com/rancher/k3s/releases/download/v0.8.0/k3s](https://github.com/rancher/k3s/releases/download/v0.8.0/k3s)[INFO] Verifying binary download[INFO] Installing k3s to /usr/local/bin/k3swhich: no kubectl in (/usr/local/bin:/usr/bin)[INFO] Creating /usr/local/bin/kubectl symlink to k3swhich: no crictl in (/usr/local/bin:/usr/bin)[INFO] Creating /usr/local/bin/crictl symlink to k3swhich: no ctr in (/usr/local/bin:/usr/bin)[INFO] Creating /usr/local/bin/ctr symlink to k3s[INFO] Creating killall script /usr/local/bin/k3s-killall.sh[INFO] Creating uninstall script /usr/local/bin/k3s-agent-uninstall.sh[INFO] env: Creating environment file /etc/systemd/system/k3s-agent.service.env[INFO] systemd: Creating service file /etc/systemd/system/k3s-agent.service[INFO] systemd: Enabling k3s-agent unitCreated symlink from /etc/systemd/system/multi-user.target.wants/k3s-agent.service to /etc/systemd/system/k3s-agent.service.[INFO] systemd: Starting k3s-agentLogs: which: no kubectl in (/usr/local/bin:/usr/bin)which: no crictl in (/usr/local/bin:/usr/bin)which: no ctr in (/usr/local/bin:/usr/bin)Created symlink from /etc/systemd/system/multi-user.target.wants/k3s-agent.service to /etc/systemd/system/k3s-agent.service.Output: [INFO] Finding latest release[INFO] Using v0.8.0 as release[INFO] Downloading hash [https://github.com/rancher/k3s/releases/download/v0.8.0/sha256sum-amd64.txt](https://github.com/rancher/k3s/releases/download/v0.8.0/sha256sum-amd64.txt)[INFO] Downloading binary [https://github.com/rancher/k3s/releases/download/v0.8.0/k3s](https://github.com/rancher/k3s/releases/download/v0.8.0/k3s)[INFO] Verifying binary download[INFO] Installing k3s to /usr/local/bin/k3s[INFO] Creating /usr/local/bin/kubectl symlink to k3s[INFO] Creating /usr/local/bin/crictl symlink to k3s[INFO] Creating /usr/local/bin/ctr symlink to k3s[INFO] Creating killall script /usr/local/bin/k3s-killall.sh[INFO] Creating uninstall script /usr/local/bin/k3s-agent-uninstall.sh[INFO] env: Creating environment file /etc/systemd/system/k3s-agent.service.env[INFO] systemd: Creating service file /etc/systemd/system/k3s-agent.service[INFO] systemd: Enabling k3s-agent unit[INFO] systemd: Starting k3s-agent[root@ip-172-31-33-136 bin]# **./kubectl get nodes**NAME STATUS ROLES AGE VERSIONip-172-31-33-136.ec2.internal Ready master 19m v1.14.5-k3s.1ip-172-31-37-118.ec2.internal Ready worker 11s v1.14.5-k3s.1

你可以看到使用k3sup设置k3s集群并在不到60秒的时间内将其作为Amazon EC2实例上运行的节点加入VM是如此容易。赶紧上手尝试吧！