mirror of https://github.com/easzlab/kubeasz.git
240 lines
10 KiB
Markdown
240 lines
10 KiB
Markdown
## 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
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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：
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- 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
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- 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
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- 所有容器之间无需NAT就可以直接互相访问
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- 所有Node和所有容器之间无需NAT就可以直接互相访问
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- 容器自己看到的IP跟其他容器看到的一样
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- 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
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- 配置网络: AddNetwork(net *NetworkConfig, rt *RuntimeConf) (types.Result, error)
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- 清理网络: DelNetwork(net *NetworkConfig, rt *RuntimeConf) error
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- IPAM Plugin负责给容器分配IP地址
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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
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- 2.然后 kubelet调用网络CNI driver，由它根据配置调用具体的CNI 插件
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- 3.然后 CNI 插件给`基础容器`配置网络
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- 4.最后 Pod 中其他的容器共享使用`基础容器`的网络
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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`。
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推荐阅读[calico kubernetes Integration Guide](https://docs.projectcalico.org/v2.6/getting-started/kubernetes/installation/integration)
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calico-node需要在所有master节点和node节点安装
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``` bash
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roles/calico/
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├── tasks
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│ └── main.yml
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└── templates
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├── calicoctl.cfg.j2
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├── calico-node.service.j2
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└── cni-calico.conf.j2
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```
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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
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{
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"CN": "calico",
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"hosts": [],
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"key": {
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"algo": "rsa",
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"size": 2048
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},
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"names": [
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{
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"C": "CN",
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"ST": "HangZhou",
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"L": "XS",
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"O": "k8s",
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"OU": "System"
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}
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]
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}
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```
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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：
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- calico/node 这个docker 容器运行时访问 etcd 使用证书
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- cni 配置文件中，cni 插件需要访问 etcd 使用证书
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- calicoctl 操作集群网络时访问 etcd 使用证书
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- 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)
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``` bash
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[Unit]
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Description=calico node
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After=docker.service
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Requires=docker.service
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[Service]
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User=root
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PermissionsStartOnly=true
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ExecStart={{ bin_dir }}/docker run --net=host --privileged --name=calico-node \
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-e ETCD_ENDPOINTS={{ ETCD_ENDPOINTS }} \
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-e ETCD_CA_CERT_FILE=/etc/calico/ssl/ca.pem \
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-e ETCD_CERT_FILE=/etc/calico/ssl/calico.pem \
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-e ETCD_KEY_FILE=/etc/calico/ssl/calico-key.pem \
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-e CALICO_LIBNETWORK_ENABLED=true \
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-e CALICO_NETWORKING_BACKEND=bird \
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-e CALICO_DISABLE_FILE_LOGGING=true \
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-e CALICO_IPV4POOL_CIDR={{ CLUSTER_CIDR }} \
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-e CALICO_IPV4POOL_IPIP=off \
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-e FELIX_DEFAULTENDPOINTTOHOSTACTION=ACCEPT \
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-e FELIX_IPV6SUPPORT=false \
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-e FELIX_LOGSEVERITYSCREEN=info \
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-e FELIX_IPINIPMTU=1440 \
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-e FELIX_HEALTHENABLED=true \
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-e IP= \
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-v /etc/calico/ssl:/etc/calico/ssl \
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-v /var/run/calico:/var/run/calico \
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-v /lib/modules:/lib/modules \
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-v /run/docker/plugins:/run/docker/plugins \
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-v /var/run/docker.sock:/var/run/docker.sock \
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-v /var/log/calico:/var/log/calico \
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calico/node:v2.6.2
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ExecStop={{ bin_dir }}/docker rm -f calico-node
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Restart=always
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RestartSec=10
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[Install]
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WantedBy=multi-user.target
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```
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+ 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
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+ 配置集群POD网络 CALICO_IPV4POOL_CIDR={{ CLUSTER_CIDR }}
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+ 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
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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)
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### 启动calico-node
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### 准备cni-calico配置文件 [cni-calico.conf.j2](../roles/calico/templates/cni-calico.conf.j2)
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``` bash
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{
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"name": "calico-k8s-network",
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"cniVersion": "0.1.0",
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"type": "calico",
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"etcd_endpoints": "{{ ETCD_ENDPOINTS }}",
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"etcd_key_file": "/etc/calico/ssl/calico-key.pem",
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"etcd_cert_file": "/etc/calico/ssl/calico.pem",
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"etcd_ca_cert_file": "/etc/calico/ssl/ca.pem",
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"log_level": "info",
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"mtu": 1500,
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"ipam": {
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"type": "calico-ipam"
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},
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"policy": {
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"type": "k8s"
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},
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"kubernetes": {
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"kubeconfig": "/root/.kube/config"
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}
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}
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```
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+ 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)
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### [可选]配置calicoctl工具 [calicoctl.cfg.j2](roles/calico/templates/calicoctl.cfg.j2)
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``` bash
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apiVersion: v1
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kind: calicoApiConfig
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metadata:
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spec:
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datastoreType: "etcdv2"
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etcdEndpoints: {{ ETCD_ENDPOINTS }}
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etcdKeyFile: /etc/calico/ssl/calico-key.pem
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etcdCertFile: /etc/calico/ssl/calico.pem
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etcdCACertFile: /etc/calico/ssl/ca.pem
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```
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### 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
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docker ps
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CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
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631dde89eada calico/node:v2.6.2 "start_runit" 10 minutes ago Up 10 minutes calico-node
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```
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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
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3: caliccc295a6d4f@if4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
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link/ether 12:79:2f:fe:8d:28 brd ff:ff:ff:ff:ff:ff link-netnsid 0
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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
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link/ipip 0.0.0.0 brd 0.0.0.0
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# 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
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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
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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
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172.20.166.128 192.168.1.36 255.255.255.192 UG 0 0 0 ens3
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```
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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
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Calico process is running.
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IPv4 BGP status
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+--------------+-------------------+-------+----------+-------------+
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| PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO |
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+--------------+-------------------+-------+----------+-------------+
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| 192.168.1.34 | node-to-node mesh | up | 12:34:00 | Established |
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| 192.168.1.35 | node-to-node mesh | up | 12:34:00 | Established |
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| 192.168.1.63 | node-to-node mesh | up | 12:34:01 | Established |
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| 192.168.1.36 | node-to-node mesh | up | 12:34:00 | Established |
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| 192.168.1.65 | node-to-node mesh | up | 12:34:00 | Established |
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| 192.168.1.37 | node-to-node mesh | up | 12:34:15 | Established |
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+--------------+-------------------+-------+----------+-------------+
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```
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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**
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``` bash
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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
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tcp 0 0 192.168.1.66:179 192.168.1.36:52823 ESTABLISHED 28479/bird
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tcp 0 0 192.168.1.66:179 192.168.1.65:56311 ESTABLISHED 28479/bird
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tcp 0 0 192.168.1.66:42000 192.168.1.37:179 ESTABLISHED 28479/bird
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tcp 0 0 192.168.1.66:179 192.168.1.34:40243 ESTABLISHED 28479/bird
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tcp 0 0 192.168.1.66:179 192.168.1.63:48979 ESTABLISHED 28479/bird
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```
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**查看集群ipPool情况**
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``` bash
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calicoctl get ipPool -o yaml
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- apiVersion: v1
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kind: ipPool
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metadata:
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cidr: 172.20.0.0/16
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spec:
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nat-outgoing: true
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```
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