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kubeasz/docs/05-安装calico网络组件.md

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## 05-安装calico网络组件.md
更新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"
}
]
}
```
然后生成证书
更新05-安装calico网络组件.md
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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
+ 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：
**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 10.100.80.1 0.0.0.0 UG 0 0 0 ens3
10.100.80.0 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 10.100.80.65 255.255.255.192 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
172.20.104.0 10.100.80.37 255.255.255.192 UG 0 0 0 ens3
172.20.166.128 10.100.80.36 255.255.255.192 UG 0 0 0 ens3
```
**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 |
+--------------+-------------------+-------+----------+-------------+
| 10.100.80.34 | node-to-node mesh | up | 12:34:00 | Established |
| 10.100.80.35 | node-to-node mesh | up | 12:34:00 | Established |
| 10.100.80.63 | node-to-node mesh | up | 12:34:01 | Established |
| 10.100.80.36 | node-to-node mesh | up | 12:34:00 | Established |
| 10.100.80.65 | node-to-node mesh | up | 12:34:00 | Established |
| 10.100.80.37 | node-to-node mesh | up | 12:34:15 | Established |
+--------------+-------------------+-------+----------+-------------+
```
**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
tcp 0 0 10.100.80.66:179 10.100.80.35:41316 ESTABLISHED 28479/bird
tcp 0 0 10.100.80.66:179 10.100.80.36:52823 ESTABLISHED 28479/bird
tcp 0 0 10.100.80.66:179 10.100.80.65:56311 ESTABLISHED 28479/bird
tcp 0 0 10.100.80.66:42000 10.100.80.37:179 ESTABLISHED 28479/bird
tcp 0 0 10.100.80.66:179 10.100.80.34:40243 ESTABLISHED 28479/bird
tcp 0 0 10.100.80.66:179 10.100.80.63:48979 ESTABLISHED 28479/bird
```
**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
```