Libnetwork
Libnetwork最初是由libcontainer和Docker Engine中的网络相关的代码合并而成的,是Docker容器网络库,最核心的内容是其定义的Container Network Model(CNM)。
Libnetwork CNM 定义了Docker容器的网络模型,按照该模型开发出的driver就能与docker daemon协同工作,实现容器网络。docker 原生的driver包括 none、bridge、overlay和macvlan,第三方driver包括flannel、weave、calico等。
CNM
CNM定义了如下三个组件:
-
Sandbox
Sandbox是Docker容器中一个网络配置的隔离环境,包含容器的interface、路由表和DNS设置。Linux Network Namespace是Sandbox的标准实现。Sandbox可以包含来自不同 Network的Endpoint。 -
Endpoint
Endpoint是一个在Network中进行网络通讯的接口(veth pair),用于将Sandbox接入Network。一个Endpoint只能属于一个Network,也只能属于一个Sandbox
Endpoint可以加入一个network,但多个Endpoint可以在一个Sandbox中共存。 - Network
一个Network就是一个唯一的、可识别的endpoint组,组内endpoint可以相互通讯。Network的实现可以是linux Bridge、VLAN等。
[root@swarm-manager ~]# ll /var/run/docker/netns/
total 0
-r--r--r-- 1 root root 0 Aug 5 10:45 1-i6xug49nwd
-r--r--r-- 1 root root 0 Aug 5 10:45 ingress_sbox
[root@swarm-manager ~]# nsenter --net=/var/run/docker/netns/ingress_sbox ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
inet 10.255.0.2 netmask 255.255.0.0 broadcast 0.0.0.0
ether 02:42:0a:ff:00:02 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.18.0.2 netmask 255.255.0.0 broadcast 0.0.0.0
ether 02:42:ac:12:00:02 txqueuelen 0 (Ethernet)
RX packets 90 bytes 75247 (73.4 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 123 bytes 10271 (10.0 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 0 (Local Loopback)
RX packets 6 bytes 504 (504.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 6 bytes 504 (504.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@swarm-manager ~]# iptables -t mangle -S
-P PREROUTING ACCEPT
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
-P POSTROUTING ACCEPT
[root@swarm-manager ~]# ipvsadm
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
[root@swarm-manager ~]# nsenter --net=/var/run/docker/netns/1-i6xug49nwd ifconfig
br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
inet 10.255.0.1 netmask 255.255.0.0 broadcast 0.0.0.0
ether 3a:31:2c:7f:21:a8 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 0 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
veth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
ether 4e:75:b1:f9:5b:55 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
vxlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
ether 3a:31:2c:7f:21:a8 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
通过nsenter --net=<SandboxKey> ip add
可以直接进入容器的Sandbox,查询相关的网络信息
load balancing
internal load balancing
vip(基于ipvs)
- 创建一个自定义的overlay网络:
只需在manager节点创建,当有Service连接该overlay网络时,将会自动在所分配的worker节点上自动创建该overlay网络。[root@swarm-manager ~]# docker network create -d overlay --subnet 192.168.10.0/24 my-network [root@swarm-manager ~]# docker network ls -f name=my-network NETWORK ID NAME DRIVER SCOPE nvpbs39b6ctz my-network overlay swarm [root@swarm-manager ~]# docker network inspect -f {{.IPAM.Config}} my-network [{192.168.10.0/24 192.168.10.1 map[]}]
- 创建一个连接到自定义的overlay网络的service(未指定"endpoint-mode"则默认为VIP模式)
Docker会为每个overlay网络创建一个独立的network namespace,其中会有一个linux bridge br0,endpoint还是由veth pair实现,一端连接到容器中的eth0,另一端连接到network namespace的br0上。br0除了连接所有的endpoint,还会连接一个vxlan设备,用于与其他host建立vxlan tunnel。容器之间的数据就是通过这个tunnel通信的。
[root@swarm-manager ~]# docker service create --replicas 2 --name nginx-vip --network my-network nginx
[root@swarm-manager ~]# docker service inspect -f {{.Endpoint.VirtualIPs}} nginx-vip
[{nvpbs39b6ctzrfw6vj809kjbu 192.168.10.2/24}]
[root@swarm-node1 ~]# ls -lrt /var/run/docker/netns/
total 0
-r--r--r--. 1 root root 0 Aug 6 11:24 ingress_sbox
-r--r--r--. 1 root root 0 Aug 6 11:24 1-i6xug49nwd
-r--r--r--. 1 root root 0 Aug 10 16:30 1-vxe1cwk14a
-r--r--r--. 1 root root 0 Aug 10 16:30 18531514ffd0
[root@swarm-node1 ~]# nsenter --net=/var/run/docker/netns/1-vxe1cwk14a ifconfig
br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
inet 192.168.10.1 netmask 255.255.255.0 broadcast 0.0.0.0
ether 5a:f5:4c:f3:98:d5 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 0 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
veth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
ether 96:57:63:17:80:83 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
vxlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
ether 5a:f5:4c:f3:98:d5 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@swarm-node1 ~]# nsenter --net=/var/run/docker/netns/18531514ffd0 ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
inet 192.168.10.4 netmask 255.255.255.0 broadcast 0.0.0.0
ether 02:42:c0:a8:0a:04 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.18.0.3 netmask 255.255.0.0 broadcast 0.0.0.0
ether 02:42:ac:12:00:03 txqueuelen 0 (Ethernet)
RX packets 7484 bytes 16821353 (16.0 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 4780 bytes 321518 (313.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 0 (Local Loopback)
RX packets 14 bytes 1717 (1.6 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 14 bytes 1717 (1.6 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
- service-name将通过内置的DNS解析到VIP地址
[root@swarm-node1 ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d66e400533af nginx:latest "nginx -g 'daemon ..." 18 minutes ago Up 18 minutes 80/tcp nginx-vip.2.p52ud6cmmgonl236dtvhuzibk
# docker exec -it d66e400533af sh
root@d66e400533af:/# nslookup nginx-vip
Server: 127.0.0.11
Address: 127.0.0.11#53
Non-authoritative answer:
Name: nginx-vip
Address: 192.168.10.2
root@d66e400533af:/# nslookup tasks.nginx-vip
Server: 127.0.0.11
Address: 127.0.0.11#53
Non-authoritative answer:
Name: tasks.nginx-vip
Address: 192.168.10.4
Name: tasks.nginx-vip
Address: 192.168.10.3
- Service IP:
192.168.10.2
在iptables的mangle表的OUTPUT链中被标记为0x112(274),IPVS通过该标记将Service IP转发到192.168.10.3和192.168.10.4的容器[root@swarm-node1 ~]# docker inspect -f {{.NetworkSettings.SandboxKey}} d66e400533af /var/run/docker/netns/18531514ffd0 [root@swarm-node1 ~]# nsenter --net=/var/run/docker/netns/18531514ffd0 sh sh-4.2# ip add show eth0 102: eth0@if103: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UP link/ether 02:42:c0:a8:0a:04 brd ff:ff:ff:ff:ff:ff link-netnsid 0 inet 192.168.10.4/24 scope global eth0 valid_lft forever preferred_lft forever inet 192.168.10.2/32 scope global eth0 valid_lft forever preferred_lft forever sh-4.2# ip route default via 172.18.0.1 dev eth1 172.18.0.0/16 dev eth1 proto kernel scope link src 172.18.0.3 192.168.10.0/24 dev eth0 proto kernel scope link src 192.168.10.4 sh-4.2# iptables -t mangle -S -P PREROUTING ACCEPT -P INPUT ACCEPT -P FORWARD ACCEPT -P OUTPUT ACCEPT -P POSTROUTING ACCEPT -A OUTPUT -d 192.168.10.2/32 -j MARK --set-xmark 0x112/0xffffffff sh-4.2# ipvsadm IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn FWM 274 rr -> 192.168.10.3:0 Masq 1 0 0 -> 192.168.10.4:0 Masq 1 0 0
VIP模式中,swarm mode为容器分配了一个连接到overlay网络(my-network)的网卡
"eth0@if103"
且生成了VIP,同时也分配了一个连接到docker_gwbridge网络的网卡"eth1@if105"
用于连接外部网络。
所有连接到my-network网络中的容器可以通过service-name或者VIP来访问service,通过service-name访问时,将先通过内置的DNS服务解析获取到VIP。
dnsrr(DNS round-robin)
-
创建一个连接到自定义的overlay网络的service,并指定endpoint-mode为dnsrr
[root@swarm-manager ~]# docker service create --endpoint-mode dnsrr --replicas 2 --name nginx-dnsrr --network my-network nginx [root@swarm-manager ~]# docker service inspect -f {{.Spec.EndpointSpec.Mode}} nginx-dnsrr dnsrr [root@swarm-node1 ~]# docker inspect -f {{.NetworkSettings.SandboxKey}} b68f0b4465b4 /var/run/docker/netns/b4efcf686a74 [root@swarm-node1 ~]# ls -lrt /var/run/docker/netns/ total 0 -r--r--r--. 1 root root 0 Aug 6 11:24 ingress_sbox -r--r--r--. 1 root root 0 Aug 6 11:24 1-i6xug49nwd -r--r--r--. 1 root root 0 Aug 10 16:30 1-vxe1cwk14a -r--r--r--. 1 root root 0 Aug 10 16:30 18531514ffd0 -r--r--r--. 1 root root 0 Aug 10 18:08 b4efcf686a74 [root@swarm-node1 ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES b68f0b4465b4 nginx:latest "nginx -g 'daemon ..." About a minute ago Up About a minute 80/tcp nginx-dnsrr.2.kpx2tqqmdugdpwpdwynbyzf9j d66e400533af nginx:latest "nginx -g 'daemon ..." 2 hours ago Up 2 hours 80/tcp nginx-vip.2.p52ud6cmmgonl236dtvhuzibk
- service-name将通过内置的DNS解析到每个容器的overlay网络地址
[root@swarm-node1 ~]# docker exec -it b68f0b4465b4 bash
root@b68f0b4465b4:/# nslookup nginx-dnsrr
Server: 127.0.0.11
Address: 127.0.0.11#53
Non-authoritative answer:
Name: my-nginx-dnsrr
Address: 192.168.10.5
Name: my-nginx-dnsrr
Address: 192.168.10.6
root@b68f0b4465b4:/# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
inet 192.168.10.6 netmask 255.255.255.0 broadcast 0.0.0.0
ether 02:42:c0:a8:0a:06 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.18.0.4 netmask 255.255.0.0 broadcast 0.0.0.0
ether 02:42:ac:12:00:04 txqueuelen 0 (Ethernet)
RX packets 7656 bytes 16832156 (16.0 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 5053 bytes 343122 (335.0 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 0 (Local Loopback)
RX packets 6 bytes 788 (788.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 6 bytes 788 (788.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ingress load balancing
- 创建一个连接到自定义的overlay网络的service,并将容器的80端口映射host的80端口
[root@swarm-manager ~]# docker service create --replicas 2 --name nginx-ingress --network my-network --publish 80:80 nginx
[root@swarm-manager ~]# docker service ls
ID NAME MODE REPLICAS IMAGE PORTS
7yzee08a9ryq nginx-dnsrr replicated 2/2 nginx:latest
qx5epc99yu8q nginx-vip replicated 2/2 nginx:latest
udiaexlplqq2 nginx-ingress replicated 2/2 nginx:latest *:80->80/tcp
[root@swarm-manager ~]# docker service inspect -f {{.Endpoint.VirtualIPs}} nginx-ingress
[{i6xug49nwdsxauqqpli3apvym 10.255.0.5/16} {vxe1cwk14avlfp2xjgymhkhdl 192.168.10.7/24}]
[root@swarm-node1 ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
42aed469b4cc nginx:latest "nginx -g 'daemon ..." About an hour ago Up About an hour 80/tcp nginx-ingress.2.u00j8ich8cv4bo0grx1hbsr7q
b68f0b4465b4 nginx:latest "nginx -g 'daemon ..." About an hour ago Up About an hour 80/tcp nginx-dnsrr.2.kpx2tqqmdugdpwpdwynbyzf9j
d66e400533af nginx:latest "nginx -g 'daemon ..." 3 hours ago Up 3 hours 80/tcp nginx-vip.2.p52ud6cmmgonl236dtvhuzibk
[root@swarm-node1 ~]# docker exec -it 42aed469b4cc bash
root@42aed469b4cc:/# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
inet 10.255.0.7 netmask 255.255.0.0 broadcast 0.0.0.0
ether 02:42:0a:ff:00:07 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.18.0.5 netmask 255.255.0.0 broadcast 0.0.0.0
ether 02:42:ac:12:00:05 txqueuelen 0 (Ethernet)
RX packets 4049 bytes 10745529 (10.2 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 3164 bytes 211730 (206.7 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
inet 192.168.10.9 netmask 255.255.255.0 broadcast 0.0.0.0
ether 02:42:c0:a8:0a:09 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 0 (Local Loopback)
RX packets 4 bytes 620 (620.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 4 bytes 620 (620.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
root@42aed469b4cc:/# ip add show eth0
110: eth0@if111: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UP group default
link/ether 02:42:0a:ff:00:07 brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet 10.255.0.7/16 scope global eth0
valid_lft forever preferred_lft forever
inet 10.255.0.5/32 scope global eth0
valid_lft forever preferred_lft forever
root@42aed469b4cc:/# ip add show eth2
root@42aed469b4cc:/# ip add show eth2
114: eth2@if115: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UP group default
link/ether 02:42:c0:a8:0a:09 brd ff:ff:ff:ff:ff:ff link-netnsid 2
inet 192.168.10.9/24 scope global eth2
valid_lft forever preferred_lft forever
inet 192.168.10.7/32 scope global eth2
valid_lft forever preferred_lft forever
容器中除了lo,还创建了3个网卡:
- eth0:连接到
ingress
的网络,通过routing mesh提供外部服务访问。 - eth1:当service设置了端口映射时,swarm会为Service中的每个容器另外分配一块网卡,连接到
docker_gwbridge
网络。当容器内部主动往外发送数据时,由docker_gwbridge SNAT转发至外部网络。 - eth2:连接到
my-network
的overlay网络。
routing mesh
如果在创建Service时映射了端口,swarm mode将会
通过routing mesh在所有节点上监听80端口,即使节点上未创建相应的容器
,并通过iptables做反向NAT,当客户端访问集群中的任意节点的80端口,swarm负载均衡会将请求路由到一个活动的容器。若不想在未创建容器的节点上监听published端口,则可在映射端口时通过--publish mode=host,target=80,published=8080
进行指定。
创建完Service之后会发现Virtual IPs有两个入口,其中10.255.0.5
连接到ingress网络,192.168.10.7
是连接自定义的my-network网络。当外部客户端访问服务时,swarm负载均衡的流程如下:
1、用户访问swarm-node1上的Nginx服务(172.16.100.21:80)
2、iptables将根据-A DOCKER-INGRESS -p tcp -m tcp --dport 80 -j DNAT --to-destination 172.18.0.2:80
的规则将请求转发至ingress sanbox
中的172.18.0.2:80。
[root@swarm-node1 ~]# iptables -t nat -S
-P PREROUTING ACCEPT
-P INPUT ACCEPT
-P OUTPUT ACCEPT
-P POSTROUTING ACCEPT
-N DOCKER
-N DOCKER-INGRESS
-A PREROUTING -m addrtype --dst-type LOCAL -j DOCKER-INGRESS
-A PREROUTING -m addrtype --dst-type LOCAL -j DOCKER
-A OUTPUT -m addrtype --dst-type LOCAL -j DOCKER-INGRESS
-A OUTPUT ! -d 127.0.0.0/8 -m addrtype --dst-type LOCAL -j DOCKER
-A POSTROUTING -o docker_gwbridge -m addrtype --src-type LOCAL -j MASQUERADE
-A POSTROUTING -s 172.17.0.0/16 ! -o docker0 -j MASQUERADE
-A POSTROUTING -s 172.18.0.0/16 ! -o docker_gwbridge -j MASQUERADE
-A DOCKER -i docker0 -j RETURN
-A DOCKER -i docker_gwbridge -j RETURN
-A DOCKER-INGRESS -p tcp -m tcp --dport 80 -j DNAT --to-destination 172.18.0.2:80
-A DOCKER-INGRESS -j RETURN
3、ingress sanbox中的iptable根据不同的端口设置不同的mark(0x114/276)。
[root@swarm-node1 ~]# nsenter --net=/var/run/docker/netns/ingress_sbox iptables -t mangle -S
[root@swarm-node1 ~]# iptables -t mangle -S
-P PREROUTING ACCEPT
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
-P POSTROUTING ACCEPT
-A PREROUTING -p tcp -m tcp --dport 80 -j MARK --set-xmark 0x114/0xffffffff
-A OUTPUT -d 10.255.0.5/32 -j MARK --set-xmark 0x114/0xffffffff
4、ipvs将根据不同的mark转发到对应的real server(容器namespace);
[root@swarm-node1 ~]# nsenter --net=/var/run/docker/netns/ingress_sbox ipvsadm
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
FWM 276 rr
-> 10.255.0.6:0 Masq 1 0 0
-> 10.255.0.7:0 Masq 1 0 0
来源:51CTO
作者:Vnimos
链接:https://blog.51cto.com/vnimos/2053238