使用K3在5分钟内部署轻量级Kubernetes集群
时间：2020-02-23 14:31:32 来源:igfitidea点击:
我们想轻松轻便地部署轻量级Kubernetes集群吗？所有内存都小于40mb？ Kubernetes已经改变了如何大规模部署和管理容器化工作负载。开发人员面临的主要挑战在于设置过程和资源需求，以使Kubernetes集群正常运行。
有关生产部署的信息，请参阅：使用Ansible和Kubespray部署生产就绪的Kubernetes集群使用Rancher RKE安装生产Kubernetes集群
对于使用Kubeadm的半手动部署，请检查：在具有Ansible和Calico CNI的CentOS 7/CentOS 8上部署Kubernetes集群
为了获得开发和测试动力，用户应该能够以最少的资源利用率和较低的硬件规格来部署Kubernetes。 K3s是由Rancher团队创建和优化的微型Kubernetes发行版，可在IoT和ARM驱动的设备上运行。
由于K3经过优化以使用更少的资源，因此剥夺了一些Kubernetes功能。这些包括：旧版，alpha，非默认功能大多数树内插件(云提供商和存储插件)都可以用树外插件替换.etcd3被sqlite3替换为默认存储机制
使用K3在5分钟内部署轻量级Kubernetes集群
对于我的部署，我有三台运行Debian 10的服务器，每台服务器都有1GB的Ram和1vcpu。其中一台服务器将用作主服务器，另外两台服务器将作为工作节点。
$openstack server list +--------------------------------------+-------------------+---------+-----------------------------------+-----------+-----------+ | ID | Name | Status | Networks | Image | Flavor | +--------------------------------------+-------------------+---------+-----------------------------------+-----------+-----------+ | 4df6a6dc-26e8-4ae0-8b6e-2f97daec0ef3 | k3s-master | ACTIVE | private=10.10.1.159 | Debian-10 | m1.tiny | | 5ca13239-b745-4f62-ab11-0a27949c9b35 | k3s-node02 | ACTIVE | private=10.10.1.142 | Debian-10 | m1.tiny | | a54997f2-4d94-4718-86ab-73609b328761 | k3s-node01 | ACTIVE | private=10.10.1.126 | Debian-10 | m1.tiny | +--------------------------------------+-------------------+---------+-----------------------------------+-----------+-----------+
在每台服务器上的/etc/hosts文件中，这些服务器的A记录都被添加了A记录。
sudo tee -a /etc/hosts<<EOF 10.10.1.159 k3s-master 10.10.1.126 k3s-node01 10.10.1.142 k3s-node02 EOF
在主节点上安装K3
运行k3的方法有很多。最快的方法是通过提供的bash脚本进行安装。该脚本提供了一种方便的方式来安装到systemd或者openrc。
curl -sfL https://get.k3s.io | sh
安装输出。
[INFO] Finding latest release [INFO] Using v0.8.1 as release [INFO] Downloading hash https://github.com/rancher/k3s/releases/download/v0.8.1/sha256sum-amd64.txt [INFO] Downloading binary https://github.com/rancher/k3s/releases/download/v0.8.1/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 Created symlink /etc/systemd/system/multi-user.target.wants/k3s.service → /etc/systemd/system/k3s.service. [INFO] systemd: Starting k3s
该服务在安装后自动启动。
$systemctl status k3s
● k3s.service - Lightweight Kubernetes
Loaded: loaded (/etc/systemd/system/k3s.service; enabled; vendor preset: enabled)
Active: active (running) since Tue 2019-09-17 19:20:00 UTC; 2min 24s ago
Docs: https://k3s.io
Process: 833 ExecStartPre=/sbin/modprobe br_netfilter (code=exited, status=0/SUCCESS)
Process: 836 ExecStartPre=/sbin/modprobe overlay (code=exited, status=0/SUCCESS)
Main PID: 837 (k3s-server)
Tasks: 98
Memory: 571.1M
CGroup: /system.slice/k3s.service
├─ 837 /usr/local/bin/k3s server KillMode=process
├─ 851 containerd -c /var/lib/rancher/k3s/agent/etc/containerd/config.toml -a /run/k3s/containerd/containerd.sock --state /run/k3s/conta
├─1110 containerd-shim -namespace k8s.io -workdir /var/lib/rancher/k3s/agent/containerd/io.containerd.runtime.v1.linux/k8s.io/f6eeb59978
├─1127 /pause
├─1207 containerd-shim -namespace k8s.io -workdir /var/lib/rancher/k3s/agent/containerd/io.containerd.runtime.v1.linux/k8s.io/0baf0ca181
├─1225 /coredns -conf /etc/coredns/Corefile
├─1576 containerd-shim -namespace k8s.io -workdir /var/lib/rancher/k3s/agent/containerd/io.containerd.runtime.v1.linux/k8s.io/dcce4b7e17
├─1594 /pause
├─1599 containerd-shim -namespace k8s.io -workdir /var/lib/rancher/k3s/agent/containerd/io.containerd.runtime.v1.linux/k8s.io/50816ffba8
├─1617 /pause
├─1824 containerd-shim -namespace k8s.io -workdir /var/lib/rancher/k3s/agent/containerd/io.containerd.runtime.v1.linux/k8s.io/d0ff393609
├─1842 /bin/sh /usr/bin/entry
├─1882 containerd-shim -namespace k8s.io -workdir /var/lib/rancher/k3s/agent/containerd/io.containerd.runtime.v1.linux/k8s.io/046779175f
├─1899 /bin/sh /usr/bin/entry
├─1904 containerd-shim -namespace k8s.io -workdir /var/lib/rancher/k3s/agent/containerd/io.containerd.runtime.v1.linux/k8s.io/93f0fe2361
└─1921 /traefik --configfile=/config/traefik.toml
Sep 17 19:20:34 deb10 k3s[837]: E0917 19:20:34.714229 837 daemon_controller.go:302] kube-system/svclb-traefik failed with : error storing statu
Sep 17 19:20:34 deb10 k3s[837]: E0917 19:20:34.719452 837 daemon_controller.go:302] kube-system/svclb-traefik failed with : error storing statu
Sep 17 19:20:34 deb10 k3s[837]: I0917 19:20:34.726816 837 reconciler.go:207] operationExecutor.VerifyControllerAttachedVolume started for volum
Sep 17 19:20:34 deb10 k3s[837]: I0917 19:20:34.726836 837 reconciler.go:207] operationExecutor.VerifyControllerAttachedVolume started for volum
Sep 17 19:20:34 deb10 k3s[837]: I0917 19:20:34.726857 837 reconciler.go:207] operationExecutor.VerifyControllerAttachedVolume started for volum
Sep 17 19:20:34 deb10 k3s[837]: I0917 19:20:34.726869 837 reconciler.go:207] operationExecutor.VerifyControllerAttachedVolume started for volum
Sep 17 19:20:35 deb10 k3s[837]: I0917 19:20:35.529102 837 reconciler.go:181] operationExecutor.UnmountVolume started for volume "helm-traefik-t
Sep 17 19:20:35 deb10 k3s[837]: I0917 19:20:35.542858 837 operation_generator.go:799] UnmountVolume.TearDown succeeded for volume "kubernetes.i
Sep 17 19:20:35 deb10 k3s[837]: I0917 19:20:35.629277 837 reconciler.go:285] Volume detached for volume "helm-traefik-token-kjwrl" (UniqueName:
Sep 17 19:20:36 deb10 k3s[837]: W0917 19:20:36.355273 837 pod_container_deletor.go:75] Container "2f0c4a787b13c029d65aa865c1b473f5a7497cb6f9b92
将kubeconfig文件写入/etc/rancher/k3s/k3s.yaml：
$cat /etc/rancher/k3s/k3s.yaml
cat: /etc/rancher/k3s/k3s.yaml: Permission denied
theitroad@localhost:~$sudo cat /etc/rancher/k3s/k3s.yaml
apiVersion: v1
clusters:
- cluster:
certificate-authority-data: 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
server: https://localhost:6443
name: default
contexts:
- context:
cluster: default
user: default
name: default
current-context: default
kind: Config
preferences: {}
users:
- name: default
user:
password: 2d99cae31c075743be704bb717ceaae8
username: admin
安装的其他实用程序是：kubectlcrictlk3s-killall.shk3s-uninstall.sh
在辅助节点上安装K3
要在工作程序节点上安装，我们应该将K3S_URL以及K3S_TOKEN或者K3S_CLUSTER_SECRET环境变量一起传递。
K3S_TOKEN在第一个节点上的/var/lib/rancher/k3s/server/node-token中创建。
$sudo cat /var/lib/rancher/k3s/server/node-token K1042e2f8e353b9409472c1e0cca8457abe184dc7be3f0805109e92c50c193ceb42::node:c83acbf89a7de7026d6f6928dc270028
因此要在工作节点上安装Kubernetes，请运行：
k3s_url="https://k3s-master:6443"
k3s_token="K1042e2f8e353b9409472c1e0cca8457abe184dc7be3f0805109e92c50c193ceb42::node:c83acbf89a7de7026d6f6928dc270028"
curl -sfL https://get.k3s.io | K3S_URL=${k3s_url} K3S_TOKEN=${k3s_token} sh
安装输出：
[INFO] Finding latest release [INFO] Using v0.8.1 as release [INFO] Downloading hash https://github.com/rancher/k3s/releases/download/v0.8.1/sha256sum-amd64.txt [INFO] Downloading binary https://github.com/rancher/k3s/releases/download/v0.8.1/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 Created symlink /etc/systemd/system/multi-user.target.wants/k3s-agent.service → /etc/systemd/system/k3s-agent.service. [INFO] systemd: Starting k3s-agent
登录到主节点之一并检查集群状态。
$sudo kubectl config get-clusters NAME default $sudo kubectl cluster-info Kubernetes master is running at https://localhost:6443 CoreDNS is running at https://localhost:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy $sudo kubectl get nodes NAME STATUS ROLES AGE VERSION k3s-master Ready master 14m v1.14.6-k3s.1 k3s-node01 Ready worker 3m11s v1.14.6-k3s.1 k3s-node02 Ready worker 3m58s v1.14.6-k3s.1 $sudo kubectl get namespaces NAME STATUS AGE default Active 16m kube-node-lease Active 16m kube-public Active 16m kube-system Active 16m $sudo kubectl get endpoints -n kube-system NAME ENDPOINTS AGE kube-dns 10.42.0.2:53,10.42.0.2:53,10.42.0.2:9153 14m traefik 10.42.0.5:80,10.42.0.5:443 14m $sudo kubectl get pods -n kube-system NAME READY STATUS RESTARTS AGE coredns-b7464766c-q9frk 1/1 Running 0 15m helm-install-traefik-8dhpk 0/1 Completed 0 15m svclb-traefik-9c2j8 2/2 Running 0 4m49s svclb-traefik-bf9zd 2/2 Running 0 4m2s svclb-traefik-v2fpx 2/2 Running 0 14m traefik-5c79b789c5-k589d 1/1 Running 0 14m
使用crictl命令查看正在运行的容器。
# Master $sudo crictl ps CONTAINER ID IMAGE CREATED STATE NAME ATTEMPT POD ID acfafb50852d3 18471c10e6e4b 16 minutes ago Running traefik 0 bf8534452389f fee5ac7e88f2e 4a065d8dfa588 16 minutes ago Running lb-port-443 0 e7068ff7ab2f2 bbab5b07e5efb 4a065d8dfa588 16 minutes ago Running lb-port-80 0 e7068ff7ab2f2 65c5d1333ea04 2ee68ed074c6e 16 minutes ago Running coredns 0 435c51f4716fc # Workers $sudo crictl ps CONTAINER ID IMAGE CREATED STATE NAME ATTEMPT POD ID 7ad5c83d6466f 4a065d8dfa588 6 minutes ago Running lb-port-443 0 bf8d9fe57c3f3 c1380eabc0b33 4a065d8dfa588 6 minutes ago Running lb-port-80 0 bf8d9fe57c3f3
卸载K3s
k3s安装程序脚本将安装k3s和其他实用程序，例如" kubectl"，" crictl"，" k3s-killall.sh"和" k3s-uninstall.sh"。要卸载K3，请运行以下命令：
$k3s-uninstall.sh
