kubeasz/docs/05-安装calico网络组件.md

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## 05-安装calico网络组件.md
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推荐阅读[feiskyer-kubernetes指南](https://github.com/feiskyer/kubernetes-handbook) 网络相关内容
首先回顾下K8S网络设计原则在配置集群网络插件或者实践K8S 应用/服务部署请时刻想到这些原则:
- 1.每个Pod都拥有一个独立IP地址Pod内所有容器共享一个网络命名空间
- 2.集群内所有Pod都在一个直接连通的扁平网络中可通过IP直接访问
- 所有容器之间无需NAT就可以直接互相访问
- 所有Node和所有容器之间无需NAT就可以直接互相访问
- 容器自己看到的IP跟其他容器看到的一样
- 3.Service cluster IP尽可在集群内部访问外部请求需要通过NodePort、LoadBalance或者Ingress来访问
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`Container Network Interface (CNI)`是目前CNCF主推的网络模型它由两部分组成
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- CNI Plugin负责给容器配置网络它包括两个基本的接口
- 配置网络: AddNetwork(net *NetworkConfig, rt *RuntimeConf) (types.Result, error)
- 清理网络: DelNetwork(net *NetworkConfig, rt *RuntimeConf) error
- IPAM Plugin负责给容器分配IP地址
Kubernetes Pod的网络是这样创建的
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- 0.每个Pod除了创建时指定的容器外都有一个kubelet启动时指定的`基础容器`,比如:`mirrorgooglecontainers/pause-amd64` `registry.access.redhat.com/rhel7/pod-infrastructure`
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- 1.首先 kubelet创建`基础容器`生成network namespace
- 2.然后 kubelet调用网络CNI driver由它根据配置调用具体的CNI 插件
- 3.然后 CNI 插件给`基础容器`配置网络
- 4.最后 Pod 中其他的容器共享使用`基础容器`的网络
本文档基于CNI driver 调用calico 插件来配置kubernetes的网络常用CNI插件有 `flannel` `calico` `weave`等等这些插件各有优势也在互相借鉴学习优点比如在所有node节点都在一个二层网络时候flannel提供hostgw实现避免vxlan实现的udp封装开销估计是目前最高效的calico也针对L3 Fabric推出了IPinIP的选项利用了GRE隧道封装因此这些插件都能适合很多实际应用场景这里选择calico主要考虑它支持 `kubernetes network policy`
推荐阅读[calico kubernetes Integration Guide](https://docs.projectcalico.org/v2.6/getting-started/kubernetes/installation/integration)
calico-node需要在所有master节点和node节点安装
``` bash
roles/calico/
├── tasks
│   └── main.yml
└── templates
├── calicoctl.cfg.j2
├── calico-node.service.j2
└── cni-calico.conf.j2
```
请在另外窗口打开[roles/calico/tasks/main.yml](../roles/calico/tasks/main.yml) 文件,对照看以下讲解内容。
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### 创建calico 证书申请
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``` bash
{
"CN": "calico",
"hosts": [],
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "CN",
"ST": "HangZhou",
"L": "XS",
"O": "k8s",
"OU": "System"
}
]
}
```
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- calico 使用客户端证书所以hosts字段可以为空后续可以看到calico证书用在四个地方
- calico/node 这个docker 容器运行时访问 etcd 使用证书
- cni 配置文件中cni 插件需要访问 etcd 使用证书
- calicoctl 操作集群网络时访问 etcd 使用证书
- calico/kube-controllers 同步集群网络策略时访问 etcd 使用证书
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### 创建 calico-node 的服务文件 [calico-node.service.j2](../roles/calico/templates/calico-node.service.j2)
``` bash
[Unit]
Description=calico node
After=docker.service
Requires=docker.service
[Service]
User=root
PermissionsStartOnly=true
ExecStart={{ bin_dir }}/docker run --net=host --privileged --name=calico-node \
-e ETCD_ENDPOINTS={{ ETCD_ENDPOINTS }} \
-e ETCD_CA_CERT_FILE=/etc/calico/ssl/ca.pem \
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-e ETCD_CERT_FILE=/etc/calico/ssl/calico.pem \
-e ETCD_KEY_FILE=/etc/calico/ssl/calico-key.pem \
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-e CALICO_LIBNETWORK_ENABLED=true \
-e CALICO_NETWORKING_BACKEND=bird \
-e CALICO_DISABLE_FILE_LOGGING=true \
-e CALICO_IPV4POOL_CIDR={{ CLUSTER_CIDR }} \
-e CALICO_IPV4POOL_IPIP=off \
-e FELIX_DEFAULTENDPOINTTOHOSTACTION=ACCEPT \
-e FELIX_IPV6SUPPORT=false \
-e FELIX_LOGSEVERITYSCREEN=info \
-e FELIX_IPINIPMTU=1440 \
-e FELIX_HEALTHENABLED=true \
-e IP= \
-v /etc/calico/ssl:/etc/calico/ssl \
-v /var/run/calico:/var/run/calico \
-v /lib/modules:/lib/modules \
-v /run/docker/plugins:/run/docker/plugins \
-v /var/run/docker.sock:/var/run/docker.sock \
-v /var/log/calico:/var/log/calico \
calico/node:v2.6.2
ExecStop={{ bin_dir }}/docker rm -f calico-node
Restart=always
RestartSec=10
[Install]
WantedBy=multi-user.target
```
+ 详细配置参数请参考[calico官方文档](https://docs.projectcalico.org/v2.6/reference/node/configuration)
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+ calico-node是以docker容器运行在host上的因此需要把之前的证书目录 /etc/calico/ssl挂载到容器中
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+ 配置ETCD_ENDPOINTS 、CA、证书等所有{{ }}变量与ansible hosts文件中设置对应
+ 配置集群POD网络 CALICO_IPV4POOL_CIDR={{ CLUSTER_CIDR }}
+ 本K8S集群运行在自有kvm虚机上虚机间没有网络ACL限制因此可以设置`CALICO_IPV4POOL_IPIP=off`,如果运行在公有云虚机上可能需要打开这个选项 `CALICO_IPV4POOL_IPIP=always`
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+ 配置FELIX_DEFAULTENDPOINTTOHOSTACTION=ACCEPT 默认允许Pod到Node的网络流量更多[felix配置选项](https://docs.projectcalico.org/v2.6/reference/felix/configuration)
### 启动calico-node
### 准备cni-calico配置文件 [cni-calico.conf.j2](../roles/calico/templates/cni-calico.conf.j2)
``` bash
{
"name": "calico-k8s-network",
"cniVersion": "0.1.0",
"type": "calico",
"etcd_endpoints": "{{ ETCD_ENDPOINTS }}",
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"etcd_key_file": "/etc/calico/ssl/calico-key.pem",
"etcd_cert_file": "/etc/calico/ssl/calico.pem",
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"etcd_ca_cert_file": "/etc/calico/ssl/ca.pem",
"log_level": "info",
"mtu": 1500,
"ipam": {
"type": "calico-ipam"
},
"policy": {
"type": "k8s"
},
"kubernetes": {
"kubeconfig": "/root/.kube/config"
}
}
```
+ 主要配置etcd相关、ipam、policy等配置选项[参考](https://docs.projectcalico.org/v2.6/reference/cni-plugin/configuration)
### [可选]配置calicoctl工具 [calicoctl.cfg.j2](roles/calico/templates/calicoctl.cfg.j2)
``` bash
apiVersion: v1
kind: calicoApiConfig
metadata:
spec:
datastoreType: "etcdv2"
etcdEndpoints: {{ ETCD_ENDPOINTS }}
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etcdKeyFile: /etc/calico/ssl/calico-key.pem
etcdCertFile: /etc/calico/ssl/calico.pem
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etcdCACertFile: /etc/calico/ssl/ca.pem
```
### 验证calico网络
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执行calico安装 `ansible-playbook 05.calico.yml` 成功后可以验证如下:(需要等待calico/node:v2.6.2 镜像下载完成有时候即便上一步已经配置了docker国内加速还是可能比较慢建议确认以下容器运行起来以后再执行后续步骤)
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``` bash
docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
631dde89eada calico/node:v2.6.2 "start_runit" 10 minutes ago Up 10 minutes calico-node
```
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**查看网卡和路由信息**
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``` bash
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ip a #...省略其他网卡信息可以看到包含类似cali1cxxx的网卡
3: caliccc295a6d4f@if4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
link/ether 12:79:2f:fe:8d:28 brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet6 fe80::1079:2fff:fefe:8d28/64 scope link
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valid_lft forever preferred_lft forever
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5: tunl0@NONE: <NOARP> mtu 1480 qdisc noop state DOWN group default qlen 1
link/ipip 0.0.0.0 brd 0.0.0.0
# tunl0网卡现在不用管是默认生成的当开启IPIP 特性时使用的隧道
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route -n
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Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
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0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 ens3
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 ens3
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172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0
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172.20.3.64 192.168.1.65 255.255.255.192 UG 0 0 0 ens3
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172.20.33.128 0.0.0.0 255.255.255.192 U 0 0 0 *
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172.20.33.129 0.0.0.0 255.255.255.255 UH 0 0 0 caliccc295a6d4f
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172.20.104.0 192.168.1.37 255.255.255.192 UG 0 0 0 ens3
172.20.166.128 192.168.1.36 255.255.255.192 UG 0 0 0 ens3
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```
**查看所有calico节点状态**
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``` bash
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calicoctl node status
Calico process is running.
IPv4 BGP status
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+--------------+-------------------+-------+----------+-------------+
| PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO |
+--------------+-------------------+-------+----------+-------------+
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| 192.168.1.34 | node-to-node mesh | up | 12:34:00 | Established |
| 192.168.1.35 | node-to-node mesh | up | 12:34:00 | Established |
| 192.168.1.63 | node-to-node mesh | up | 12:34:01 | Established |
| 192.168.1.36 | node-to-node mesh | up | 12:34:00 | Established |
| 192.168.1.65 | node-to-node mesh | up | 12:34:00 | Established |
| 192.168.1.37 | node-to-node mesh | up | 12:34:15 | Established |
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+--------------+-------------------+-------+----------+-------------+
```
**BGP 协议是通过TCP 连接来建立邻居的因此可以用netstat 命令验证 BGP Peer**
``` bash
netstat -antlp|grep ESTABLISHED|grep 179
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tcp 0 0 192.168.1.66:179 192.168.1.35:41316 ESTABLISHED 28479/bird
tcp 0 0 192.168.1.66:179 192.168.1.36:52823 ESTABLISHED 28479/bird
tcp 0 0 192.168.1.66:179 192.168.1.65:56311 ESTABLISHED 28479/bird
tcp 0 0 192.168.1.66:42000 192.168.1.37:179 ESTABLISHED 28479/bird
tcp 0 0 192.168.1.66:179 192.168.1.34:40243 ESTABLISHED 28479/bird
tcp 0 0 192.168.1.66:179 192.168.1.63:48979 ESTABLISHED 28479/bird
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```
**查看集群ipPool情况**
``` bash
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calicoctl get ipPool -o yaml
- apiVersion: v1
kind: ipPool
metadata:
cidr: 172.20.0.0/16
spec:
nat-outgoing: true
```
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