• 安装flannel网络插件

    安装flannel网络插件

    所有的node节点都需要安装网络插件才能让所有的Pod加入到同一个局域网中，本文是安装flannel网络插件的参考文档。

    建议直接使用yum安装flanneld，除非对版本有特殊需求，默认安装的是0.7.1版本的flannel。

    1. yum install -y flannel

    service配置文件/usr/lib/systemd/system/flanneld.service。

    1. [Unit]
    2. Description=Flanneld overlay address etcd agent
    3. After=network.target
    4. After=network-online.target
    5. Wants=network-online.target
    6. After=etcd.service
    7. Before=docker.service
    9. [Service]
    10. Type=notify
    11. EnvironmentFile=/etc/sysconfig/flanneld
    12. EnvironmentFile=-/etc/sysconfig/docker-network
    13. ExecStart=/usr/bin/flanneld-start \
    14.   -etcd-endpoints=${ETCD_ENDPOINTS} \
    15.   -etcd-prefix=${ETCD_PREFIX} \
    16.   $FLANNEL_OPTIONS
    17. ExecStartPost=/usr/libexec/flannel/mk-docker-opts.sh -k DOCKER_NETWORK_OPTIONS -d /run/flannel/docker
    18. Restart=on-failure
    20. [Install]
    21. WantedBy=multi-user.target
    22. RequiredBy=docker.service

    /etc/sysconfig/flanneld配置文件：

    1. # Flanneld configuration options  
    3. # etcd url location.  Point this to the server where etcd runs
    4. ETCD_ENDPOINTS="https://172.20.0.113:2379,https://172.20.0.114:2379,https://172.20.0.115:2379"
    6. # etcd config key.  This is the configuration key that flannel queries
    7. # For address range assignment
    8. ETCD_PREFIX="/kube-centos/network"
    10. # Any additional options that you want to pass
    11. FLANNEL_OPTIONS="-etcd-cafile=/etc/kubernetes/ssl/ca.pem -etcd-certfile=/etc/kubernetes/ssl/kubernetes.pem -etcd-keyfile=/etc/kubernetes/ssl/kubernetes-key.pem"

    如果是多网卡（例如vagrant环境），则需要在FLANNEL_OPTIONS中增加指定的外网出口的网卡，例如-iface=eth2

    在etcd中创建网络配置

    执行下面的命令为docker分配IP地址段。

    1. etcdctl --endpoints=https://172.20.0.113:2379,https://172.20.0.114:2379,https://172.20.0.115:2379 \
    2.   --ca-file=/etc/kubernetes/ssl/ca.pem \
    3.   --cert-file=/etc/kubernetes/ssl/kubernetes.pem \
    4.   --key-file=/etc/kubernetes/ssl/kubernetes-key.pem \
    5.   mkdir /kube-centos/network
    6. etcdctl --endpoints=https://172.20.0.113:2379,https://172.20.0.114:2379,https://172.20.0.115:2379 \
    7.   --ca-file=/etc/kubernetes/ssl/ca.pem \
    8.   --cert-file=/etc/kubernetes/ssl/kubernetes.pem \
    9.   --key-file=/etc/kubernetes/ssl/kubernetes-key.pem \
    10.   mk /kube-centos/network/config '{"Network":"172.30.0.0/16","SubnetLen":24,"Backend":{"Type":"vxlan"}}'

    如果你要使用host-gw模式，可以直接将vxlan改成host-gw即可。

    注：参考网络和集群性能测试那节，最终我们使用的host-gw模式，关于flannel支持的backend模式见：https://github.com/coreos/flannel/blob/master/Documentation/backends.md。

    启动flannel

    1. systemctl daemon-reload
    2. systemctl enable flanneld
    3. systemctl start flanneld
    4. systemctl status flanneld

    现在查询etcd中的内容可以看到：

    1. $etcdctl --endpoints=${ETCD_ENDPOINTS} \
    2.   --ca-file=/etc/kubernetes/ssl/ca.pem \
    3.   --cert-file=/etc/kubernetes/ssl/kubernetes.pem \
    4.   --key-file=/etc/kubernetes/ssl/kubernetes-key.pem \
    5.   ls /kube-centos/network/subnets
    6. /kube-centos/network/subnets/172.30.14.0-24
    7. /kube-centos/network/subnets/172.30.38.0-24
    8. /kube-centos/network/subnets/172.30.46.0-24
    9. $etcdctl --endpoints=${ETCD_ENDPOINTS} \
    10.   --ca-file=/etc/kubernetes/ssl/ca.pem \
    11.   --cert-file=/etc/kubernetes/ssl/kubernetes.pem \
    12.   --key-file=/etc/kubernetes/ssl/kubernetes-key.pem \
    13.   get /kube-centos/network/config
    14. { "Network": "172.30.0.0/16", "SubnetLen": 24, "Backend": { "Type": "vxlan" } }
    15. $etcdctl get /kube-centos/network/subnets/172.30.14.0-24
    16. {"PublicIP":"172.20.0.114","BackendType":"vxlan","BackendData":{"VtepMAC":"56:27:7d:1c:08:22"}}
    17. $etcdctl get /kube-centos/network/subnets/172.30.38.0-24
    18. {"PublicIP":"172.20.0.115","BackendType":"vxlan","BackendData":{"VtepMAC":"12:82:83:59:cf:b8"}}
    19. $etcdctl get /kube-centos/network/subnets/172.30.46.0-24
    20. {"PublicIP":"172.20.0.113","BackendType":"vxlan","BackendData":{"VtepMAC":"e6:b2:fd:f6:66:96"}}

    如果可以查看到以上内容证明flannel已经安装完成，下一步是在node节点上安装和配置docker、kubelet、kube-proxy等，请参考下一节部署node节点。