k8s集群的搭建之三:flannel

一介绍

flannel是CoreOS提供用于解决Dokcer集群跨主机通讯的覆盖网络工具。它的主要思路是:预先留出一个网段,每个主机使用其中一部分,然后每个容器被分配不同的ip;
让所有的容器认为大家在同一个直连的网络,底层通过UDP/VxLAN等进行报文的封装和转发。
flannel是Overlay网络的一种,也是将源数据包封装在另一种网络包里面进行路由转发和通信,目前已经支持UDP,VXLAN,host-gw,AWS,VPC,GCE路由等级传输,推荐 vxlan或者host-gw

二搭建(这里以两台为例)

2.1 分配网段,封装类型为vxlan,高效,稳定(master上执行)

etcdctl --ca-file=/etc/etcd/ssl/etcd-root-ca.pem --cert-file=/etc/etcd/ssl/etcd.pem --key-file=/etc/etcd/ssl/etcd-key.pem   \
--endpoints=https://192.168.137.66:2379,https://192.168.137.16:2379 set /coreos.com/network/config '{ "Network": "172.17.0.0/16", "Backend": {"Type": "vxlan"}}

查看分配的结果:

[[email protected] ~]# etcdctl --ca-file=/etc/etcd/ssl/etcd-root-ca.pem --cert-file=/etc/etcd/ssl/etcd.pem --key-file=/etc/etcd/ssl/etcd-key.pem  \
--endpoints=https://192.168.137.66:2379,https://192.168.137.16:2379 get /coreos.com/network/config '{ "Network": "172.17.0.0/16", "Backend": {"Type": "vxlan"}}'
{ "Network": "172.17.0.0/16", "Backend": {"Type": "vxlan"}}

2.2 下载并安装(master上执行)

mkdir  /home/softs
cd /home/softs
wget https://github.com/coreos/flannel/releases/download/v0.11.0/flannel-v0.11.0-linux-amd64.tar.gz
tar xf flannel-v0.11.0-linux-amd64.tar.gz
mv flanneld mk-docker-opts.sh /opt/kubernetes/bin/
[[email protected] softs]# cat flanneld.sh    #这里我们继续使用上一篇中安装etcd时生成的pem证书
#!/bin/bash

ETCD_ENDPOINTS=${1:-"http://127.0.0.1:2379"}
cat <<EOF >/opt/kubernetes/cfg/flanneld
FLANNEL_OPTIONS="--etcd-endpoints=${ETCD_ENDPOINTS} \
-etcd-cafile=/etc/etcd/ssl/etcd-root-ca.pem \
-etcd-certfile=/etc/etcd/ssl/etcd.pem \
-etcd-keyfile=/etc/etcd/ssl/etcd-key.pem"
EOF

cat <<EOF >/usr/lib/systemd/system/flanneld.service
[Unit]
Description=Flanneld overlay address etcd agent
After=network-online.target network.target
Before=docker.service
[Service]
Type=notify
EnvironmentFile=/opt/kubernetes/cfg/flanneld
ExecStart=/opt/kubernetes/bin/flanneld --ip-masq \$FLANNEL_OPTIONS
ExecStartPost=/opt/kubernetes/bin/mk-docker-opts.sh -k DOCKER_NETWORK_OPTIONS -d /run/flannel/subnet.env
Restart=on-failure
[Install]
WantedBy=multi-user.target
EOF

cat <<EOF >/usr/lib/systemd/system/docker.service
[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network-online.target firewalld.service
Wants=network-online.target
[Service]
Type=notify
EnvironmentFile=/run/flannel/subnet.env
ExecStart=/usr/bin/dockerd  \$DOCKER_NETWORK_OPTIONS
ExecReload=/bin/kill -s HUP \$MAINPID
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
TimeoutStartSec=0
Delegate=yes
KillMode=process
Restart=on-failure
StartLimitBurst=3
StartLimitInterval=60s
[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl enable flanneld
systemctl restart flanneld
systemctl restart docker
sh -x flanneld.sh https://192.168.137.66:2379,https://192.168.137.16:2379

分发到节点上执行(master 上执行)

cd /home/softs
scp flanneld.sh [email protected]:/home/softs/
cd /opt/kubernetes/bin/ 
scp flanneld mk-docker-opts.sh [email protected]:/opt/kubernetes/bin/

节点上执行(各节点执行)

sh -x flanneld.sh https://192.168.137.66:2379,https://192.168.137.16:2379

2.3 查看flannel状态(都可查看)

[[email protected] softs]# etcdctl --ca-file=/etc/etcd/ssl/etcd-root-ca.pem --cert-file=/etc/etcd/ssl/etcd.pem --key-file=/etc/etcd/ssl/etcd-key.pem \
--endpoints="https://192.168.137.66:2379,https://192.168.137.16:2379" ls /coreos.com/network/subnets
/coreos.com/network/subnets/172.17.90.0-24 /coreos.com/network/subnets/172.17.84.0-24
[[email protected] softs]# etcdctl --ca-file=/etc/etcd/ssl/etcd-root-ca.pem --cert-file=/etc/etcd/ssl/etcd.pem --key-file=/etc/etcd/ssl/etcd-key.pem \
--endpoints="https://192.168.137.66:2379,https://192.168.137.16:2379" get /coreos.com/network/subnets/172.17.84.0-24 docker
{"PublicIP":"192.168.137.16","BackendType":"vxlan","BackendData":{"VtepMAC":"76:ec:3f:7c:1b:81"}}
[[email protected] softs]# etcdctl --ca-file=/etc/etcd/ssl/etcd-root-ca.pem --cert-file=/etc/etcd/ssl/etcd.pem --key-file=/etc/etcd/ssl/etcd-key.pem \ 
--endpoints="https://192.168.137.66:2379,https://192.168.137.16:2379" get /coreos.com/network/subnets/172.17.90.0-24 docker
{"PublicIP":"192.168.137.66","BackendType":"vxlan","BackendData":{"VtepMAC":"9e:51:aa:45:24:7f"}}

 查看路由情况

#master
[[email protected] bin]# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.137.1 0.0.0.0 UG 100 0 0 ens33 172.17.84.0 172.17.84.0 255.255.255.0 UG 0 0 0 flannel.1 172.17.90.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0 192.168.137.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
#node
[[email protected] softs]# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.137.1 0.0.0.0 UG 100 0 0 ens33 172.17.84.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0 172.17.90.0 172.17.90.0 255.255.255.0 UG 0 0 0 flannel.1 192.168.137.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33

 

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转载自www.cnblogs.com/mmyy-blog/p/10924033.html
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