目录
0.架构图
kubernetes设计了网络模型，但却将它的实现交给了网络插件，CNI网络插件最主要的功能主是实现pod资源能够跨宿主机进行通信。
常见的CNI网络插件：
- Flannel
- Calico
- Canal
- Contiv
- OpenContrail
- NSX-T
- Kube-router
1.Flannel三种模型
- host-gw
- VxLan
- Directrouting
1.1 host-gw模型
host-gw模型即网关模式，在服务器直接添加一条静态路由即可，效率高，各节点必须在同一网段。
10.4.7.21通过172.7.22.0这条静态路由连接10.4.7.22这台主机再连接172.7.21网段，反之亦是。
/opt/etcd/etcdctl set /coreos.com/network/config '{"Network": "172.7.0.0/16", "Backend": {"Type": "host-gw"}}'
/opt/etcd/etcdctl set /coreos.com/network/config # 查看
/opt/etcd/etcdctl rm /coreos.com/network/config # 删除
1.2 VxLAN模型
在不同网段，可以用VxLAN模式，主机A会生成一个flannel.1网卡，通过封装头从flannel.1网卡出去通过flanne隧道传出，从flannel.1网卡传入拆包，到达目标主机网卡到指向的静态路由，效率低。
/opt/etcd/etcdctl set /coreos.com/network/config '{"Network": "172.7.0.0/16", "Backend": {"Type": "VxLAN"}}'
1.3 Directrouting模型
直接路由模式，结合了VxLAN和host-gw模型，自动识别服务器，如果同网段，则使用host-gw模型，如果不同网段则使用VxLAN模型。
/opt/etcd/etcdctl set /coreos.com/network/config '{"Network": "172.7.0.0/16", "Backend": {"Type": "VxLAN","Directrouting": true}}'
1.4 Flannel部署
1.4.1 集群规划
| 主机名 | IP | 角色 | 节点 |
|---|---|---|---|
| hdss7-21.host.com | 10.4.7.21 | Flannel | Node |
| hdss7-22.host.com | 10.4.7.22 | Flannel | Node |
1.4.2 下载解压
在hdss21-host.com操作，hdss22-host.com操作类似。
下载链接：https://github.com/coreos/flannel/releases
cd /opt/src
rz ==> flannel-v0.12.0-linux-amd64.tar.gz
mkdir /opt/flanneld-v0.12.0
tar xf flannel-v0.12.0-linux-amd64.tar.gz -C /opt/flanneld-v0.12.0
ln -s /opt/flanneld-v0.12.0 /opt/flannel
1.4.3 创建配置
cat > /opt/flannel/subnet.env <<'eof'
FLANNEL_NETWORK=172.7.0.0/16
FLANNEL_SUBNET=172.7.21.1/24
FLANNEL_MTU=1500
FLANNEL_IPMASQ=false
eof
注：不同地方
172.4.7.21 配置 FLANNEL_SUBNET=172.7.21.1/24
172.4.7.22 配置 FLANNEL_SUBNET=172.7.22.1/24
1.4.4 拷贝证书
mkdir /opt/flannel/certs
scp hdss7-200:/opt/certs/ca.pem /opt/flannel/certs/
scp hdss7-200:/opt/certs/client.pem /opt/flannel/certs/
scp hdss7-200:/opt/certs/client-key.pem /opt/flannel/certs/
1.4.5 创建启动脚本
cat > /opt/flannel/flanneld.sh <<'eof'
#!/bin/sh
./flanneld
--public-ip=10.4.7.21
--etcd-endpoints=https://10.4.7.12:2379,https://10.4.7.21:2379,https://10.4.7.22:2379
--etcd-keyfile=./certs/client-key.pem
--etcd-certfile=./certs/client.pem
--etcd-cafile=./certs/ca.pem
--iface=ens33
--subnet-file=./subnet.env
--healthz-port=2401
eof
chmod +x /opt/flannel/flanneld.sh
mkdir -p /data/logs/flanneld
注：不同地方
172.4.7.21 配置 -public-ip=10.4.7.21
172.4.7.22 配置 -public-ip=10.4.7.22
–iface=ens33 配置为服务器网卡名
1.4.6 创建supervisor配置
cat > /etc/supervisord.d/flanneld.ini << 'eof'
[program:flanneld-7-21]
command=/opt/flannel/flanneld.sh ; the program (relative uses PATH, can take args)
numprocs=1 ; number of processes copies to start (def 1)
directory=/opt/flannel ; directory to cwd to before exec (def no cwd)
autostart=true ; start at supervisord start (default: true)
autorestart=true ; retstart at unexpected quit (default: true)
startsecs=22 ; number of secs prog must stay running (def. 1)
startretries=3 ; max # of serial start failures (default 3)
exitcodes=0,2 ; 'expected' exit codes for process (default 0,2)
stopsignal=QUIT ; signal used to kill process (default TERM)
stopwaitsecs=10 ; max num secs to wait b4 SIGKILL (default 10)
user=root ; setuid to this UNIX account to run the program
redirect_stderr=false ; redirect proc stderr to stdout (default false)
stdout_logfile=/data/logs/flanneld/flanneld.stdout.log ; stdout log path, NONE for none; default AUTO
stdout_logfile_maxbytes=64MB ; max # logfile bytes b4 rotation (default 50MB)
stdout_logfile_backups=4 ; # of stdout logfile backups (default 10)
stdout_capture_maxbytes=1MB ; number of bytes in 'capturemode' (default 0)
stdout_events_enabled=false ; emit events on stdout writes (default false)
stderr_logfile=/data/logs/flanneld/flanneld.stderr.log ; stderr log path, NONE for none; default AUTO
stderr_logfile_maxbytes=64MB ; max # logfile bytes b4 rotation (default 50MB)
stderr_logfile_backups=4 ; # of stderr logfile backups (default 10)
stderr_capture_maxbytes=1MB ; number of bytes in 'capturemode' (default 0)
stderr_events_enabled=false
eof
注：不同地方[program:flanneld-7-21]
1.5 使用host-gw模型
hdss21-host.com操作，任意一台etcd机器操作都可以。
/opt/etcd/etcdctl set /coreos.com/network/config '{"Network": "172.7.0.0/16", "Backend": {"Type": "host-gw"}}'
supervisorctl update
supervisorctl status
[root@hdss7-22 ~]# route -n # 在22主机上可看到添加了一条10.4.7.21的静态路由
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.4.7.254 0.0.0.0 UG 100 0 0 ens33
10.4.7.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
172.7.21.0 10.4.7.21 255.255.255.0 UG 0 0 0 ens33
172.7.22.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0
[root@hdss7-21 ~]# route -n # 在21主机上可看到添加了一条10.4.7.22的静态路由
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.4.7.254 0.0.0.0 UG 100 0 0 ens33
10.4.7.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
172.7.21.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0
172.7.22.0 10.4.7.22 255.255.255.0 UG 0 0 0 ens33
[root@hdss7-21 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
my-nginx-h88nr 1/1 Running 1 3h46m 172.7.22.2 hdss7-22.host.com <none> <none>
my-nginx-vrlsk 1/1 Running 0 3h46m 172.7.21.2 hdss7-21.host.com <none> <none>
[root@hdss7-21 ~]# ping 172.7.22.2
[root@hdss7-22 ~]# ping 172.7.21.2
由于flanned网络的gw模型是直接帮你添加一条静态路由，若不用flanned插件，可自行添加路由打通网络
10.4.7.21上操作:
route add -net 172.7.22.0/24 gw 10.4.7.22
iptables -I FORWARD -d 172.7.21.0/24 -j ACCEPT
10.4.7.22上操作:
route add -net 172.7.21.0/24 gw 10.4.7.21
iptables -I FORWARD -d 172.7.22.0/24 -j ACCEPT
1.6 使用VxLAN模型
- 关闭两台机器flannel
- 删除两台机器先前添加的静态路由
- 删除etc先前的设置重新添加新模型保存
- 启动flannel查看网卡
[root@hdss7-21 ~]# supervisorctl stop flanneld
[root@hdss7-22 ~]# supervisorctl stop flanneld
[root@hdss7-22 ~]# route del -net 172.7.21.0/24 gw 10.4.7.21
[root@hdss7-21 ~]# route del -net 172.7.22.0/24 gw 10.4.7.22
[root@hdss7-21 ~]# /opt/etcd/etcdctl rm /coreos.com/network/config
[root@hdss7-21 ~]# /opt/etcd/etcdctl set /coreos.com/network/config '{"Network": "172.7.0.0/16", "Backend": {"Type": "VxLAN"}}'
[root@hdss7-21 ~]# /opt/etcd/etcdctl get /coreos.com/network/config
[root@hdss7-21 ~]# supervisorctl start flanneld
[root@hdss7-22 ~]# supervisorctl start flanneld
[root@hdss7-21 ~]# ifconfig flannel.1
flannel.1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
inet 172.7.21.0 netmask 255.255.255.255 broadcast 0.0.0.0
inet6 fe80::803:ff:fe6d:1f33 prefixlen 64 scopeid 0x20<link>
ether 0a:03:00:6d:1f:33 txqueuelen 0 (Ethernet)
RX packets 10 bytes 2234 (2.1 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 14 bytes 892 (892.0 B)
TX errors 0 dropped 8 overruns 0 carrier 0 collisions 0
[root@hdss7-22 etcd]# ifconfig flannel.1
flannel.1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
inet 172.7.22.0 netmask 255.255.255.255 broadcast 0.0.0.0
inet6 fe80::d0c2:4bff:fe29:df00 prefixlen 64 scopeid 0x20<link>
ether d2:c2:4b:29:df:00 txqueuelen 0 (Ethernet)
RX packets 14 bytes 892 (892.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 10 bytes 2234 (2.1 KiB)
TX errors 0 dropped 8 overruns 0 carrier 0 collisions 0
[root@hdss7-22 etcd]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.4.7.254 0.0.0.0 UG 100 0 0 ens33
10.4.7.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
172.7.21.0 172.7.21.0 255.255.255.0 UG 0 0 0 flannel.1
172.7.22.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0
[root@hdss7-21 ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.4.7.254 0.0.0.0 UG 100 0 0 ens33
10.4.7.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
172.7.21.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0
172.7.22.0 172.7.22.0 255.255.255.0 UG 0 0 0 flannel.1
[root@hdss7-21 ~]# ping 172.7.22.2
[root@hdss7-22 ~]# ping 172.7.21.2
1.7 使用Directrouting模型
hdss7-21主机操作为例，7-22操作类似
supervisorctl stop flanneld
[root@hdss7-21 ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.4.7.254 0.0.0.0 UG 100 0 0 ens33
10.4.7.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
172.7.21.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0
172.7.22.0 172.7.22.0 255.255.255.0 UG 0 0 0 flannel.1
route del -net 172.7.22.0/24 gw 172.7.22.0 # 删除旧flannel路由
/opt/etcd/etcdctl rm /coreos.com/network/config # 删除旧数据
/opt/etcd/etcdctl set /coreos.com/network/config '{"Network": "172.7.0.0/16", "Backend": {"Type": "VxLAN","Directrouting": true}}' #设置新数据
/opt/etcd/etcdctl get /coreos.com/network/config
supervisorctl start flanneld
[root@hdss7-21 ~]# route -n # 由于服务器同网段直接路由模型使用host-gw模型
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.4.7.254 0.0.0.0 UG 100 0 0 ens33
10.4.7.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
172.7.21.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0
172.7.22.0 10.4.7.22 255.255.255.0 UG 0 0 0 ens33
[root@hdss7-21 ~]# ping 172.7.22.2