# K8s add Nodes（join）

### 環境準備

我準備了兩個 VM 當 K8s work node，加入我的 K8s Lab 叢集環境。\
先進行 kubeadm 套件安裝：\
安裝 kubeadm：<https://fufu.gitbook.io/kk8s/installing-kubeadm#jing-xu-qiu>\
安裝 CRI-O：<https://fufu.gitbook.io/kk8s/installing-crio-kubeadm-init#install-cri-o>&#x20;

因採用非預設的 CRI，故需指定 cgroup-driver

```bash
[vagrant@kk8s-1 ~]$ sudo vi /etc/systemd/system/kubelet.service.d/10-kubeadm.conf
Environment="KUBELET_CGROUP_ARGS=--cgroup-driver=systemd"
ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS $KUBELET_CGROUP_ARGS

```

### 進行 node join

過程中遇到兩個問題，記錄下來：

#### 錯誤1：IPVS proxier will not be used

```bash
[WARNING RequiredIPVSKernelModulesAvailable]: 
the IPVS proxier will not be used, because the following required kernel modules are not loaded: 
[ip_vs ip_vs_rr ip_vs_wrr ip_vs_sh] or no builtin kernel ipvs support: 
map[ip_vs:{} ip_vs_rr:{} ip_vs_wrr:{} ip_vs_sh:{} nf_conntrack_ipv4:{}]

you can solve this problem with following methods:
  1. Run 'modprobe -- ' to load missing kernel modules;
  2. Provide the missing builtin kernel ipvs support
```

經過 Google 搜尋網友經驗，需要下這些指令：

```bash
sudo modprobe ip_vs_rr
sudo modprobe ip_vs_wrr
sudo modprobe ip_vs_sh
sudo modprobe ip_vs
sudo modprobe nf_conntrack_ipv4

# 檢查：
sudo lsmod| grep ip_vs
```

#### 錯誤2：ERROR FileAvailable

```bash
[preflight] Some fatal errors occurred:
	[ERROR FileAvailable--etc-kubernetes-kubelet.conf]: /etc/kubernetes/kubelet.conf already exists
	[ERROR FileAvailable--etc-kubernetes-bootstrap-kubelet.conf]: /etc/kubernetes/bootstrap-kubelet.conf already exists
	[ERROR FileAvailable--etc-kubernetes-pki-ca.crt]: /etc/kubernetes/pki/ca.crt already exists
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
```

這是因為我已經執行數次 join 指令，故已經產生過上述檔案。\
透過`--ignore-preflight-errors=all`即可忽略！

#### Join 指令

```bash
sudo kubeadm join 192.168.42.191:6443 --token noduzf.t2ng9nhcx2gdo53y \
--discovery-token-ca-cert-hash sha256:d02f588e50c1f16fb9eec512e5ca14fd2add98e0231805a46c4e0fb2aff83555 \
--cri-socket="/var/run/crio/crio.sock" \
--ignore-preflight-errors=all
# 成功完成 join
```

#### 錯誤3：connection to the server localhost:8080 was refused

```bash
[vagrant@kk8s-2 ~]$ kubectl get nodes
The connection to the server localhost:8080 was refused - did you specify the right host or port?

```

這是是因為存取不到 API server，需設定本機帳號 API 存取權限

```bash
mkdir -p $HOME/.kube
scp master-ip:$HOME/.kube/config $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

[vagrant@kk8s-2 ~]$ kubectl get nodes
NAME     STATUS   ROLES    AGE   VERSION
kk8s-1   Ready    master   23h   v1.12.2
kk8s-2   Ready    <none>   24m   v1.12.2
kk8s-3   Ready    <none>   17m   v1.12.2
```

#### 終於完成另一個小里程～經驗與概念又學習到了～


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://fufu.gitbook.io/kk8s/k8s-add-nodes-join.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.