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05-install_kube_node.md

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05-安装kube_node节点

kube_node 是集群中运行工作负载的节点,前置条件需要先部署好kube_master节点,它需要部署如下组件:

cat playbooks/05.kube-node.yml
- hosts: kube_node
  roles:
  - { role: kube-lb, when: "inventory_hostname not in groups['kube_master']" }
  - { role: kube-node, when: "inventory_hostname not in groups['kube_master']" }
  • kube-lb:由nginx裁剪编译的四层负载均衡,用于将请求转发到主节点的 apiserver服务
  • kubelet:kube_node上最主要的组件
  • kube-proxy: 发布应用服务与负载均衡

创建cni 基础网络插件配置文件

因为后续需要用 DaemonSet Pod方式运行k8s网络插件,所以kubelet.server服务必须开启cni相关参数,并且提供cni网络配置文件

创建 kubelet 的服务文件

  • 根据官方建议独立使用 kubelet 配置文件,详见roles/kube-node/templates/kubelet-config.yaml.j2
  • 必须先创建工作目录 /var/lib/kubelet
[Unit]
Description=Kubernetes Kubelet
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
WorkingDirectory=/var/lib/kubelet
{% if ansible_distribution == "Debian" and ansible_distribution_version|int >= 10 %}
ExecStartPre=/bin/mount -o remount,rw '/sys/fs/cgroup'
{% endif %}
{% if KUBE_RESERVED_ENABLED == "yes" or SYS_RESERVED_ENABLED == "yes" %}
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/cpu/podruntime.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/cpuacct/podruntime.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/cpuset/podruntime.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/memory/podruntime.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/pids/podruntime.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/systemd/podruntime.slice

ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/cpu/system.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/cpuacct/system.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/cpuset/system.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/memory/system.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/pids/system.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/systemd/system.slice

{% if ansible_distribution != "Debian" %}
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/hugetlb/podruntime.slice
ExecStartPre=/bin/mkdir -p /sys/fs/cgroup/hugetlb/system.slice
{% endif %}
{% endif %}
ExecStart={{ bin_dir }}/kubelet \
  --config=/var/lib/kubelet/config.yaml \
  --container-runtime-endpoint=unix:///run/containerd/containerd.sock \
  --hostname-override={{ inventory_hostname }} \
  --kubeconfig=/etc/kubernetes/kubelet.kubeconfig \
  --root-dir={{ KUBELET_ROOT_DIR }} \
  --v=2
Restart=always
RestartSec=5

[Install]
WantedBy=multi-user.target
  • --ExecStartPre=/bin/mkdir -p xxx 对于某些系统(centos7)cpuset和hugetlb 是默认没有初始化system.slice 的,需要手动创建,否则在启用--kube-reserved-cgroup 时会报错Failed to start ContainerManager Failed to enforce System Reserved Cgroup Limits
  • 关于kubelet资源预留相关配置请参考 https://kubernetes.io/docs/tasks/administer-cluster/reserve-compute-resources/

创建 kube-proxy kubeconfig 文件

该步骤已经在 deploy节点完成,roles/deploy/tasks/main.yml

  • 生成的kube-proxy.kubeconfig 配置文件需要移动到/etc/kubernetes/目录,后续kube-proxy服务启动参数里面需要指定

创建 kube-proxy服务文件

[Unit]
Description=Kubernetes Kube-Proxy Server
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=network.target

[Service]
WorkingDirectory=/var/lib/kube-proxy
ExecStart={{ bin_dir }}/kube-proxy \
  --config=/var/lib/kube-proxy/kube-proxy-config.yaml
Restart=always
RestartSec=5
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target

请注意 kube-proxy-config 文件的注释说明

验证 node 状态

systemctl status kubelet	# 查看状态
systemctl status kube-proxy
journalctl -u kubelet		# 查看日志
journalctl -u kube-proxy 

运行 kubectl get node 可以看到类似

NAME           STATUS    ROLES     AGE       VERSION
192.168.1.42   Ready     <none>    2d        v1.9.0
192.168.1.43   Ready     <none>    2d        v1.9.0
192.168.1.44   Ready     <none>    2d        v1.9.0

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