Dokcer网络

理解Docker0
1.我们每启动一个docker容器，docker就会给docker容器分配一个ip，只要安装了docker，就会有个网卡docker0，桥接模式，使用的是veth-pair技术。
veth-pair技术 就是一对的虚拟设备接口，他们都是成对出现的。

[[email protected] tomcat]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 52:54:00:84:47:c3 brd ff:ff:ff:ff:ff:ff
    inet 172.17.16.11/20 brd 172.17.31.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::5054:ff:fe84:47c3/64 scope link 
       valid_lft forever preferred_lft forever
3: [email protected]: <NOARP,UP,LOWER_UP> mtu 1480 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ipip 0.0.0.0 brd 0.0.0.0
    inet 10.244.39.0/32 scope global tunl0
       valid_lft forever preferred_lft forever
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:0b:8c:68:23 brd ff:ff:ff:ff:ff:ff
    inet 172.18.0.1/16 brd 172.18.255.255 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:bff:fe8c:6823/64 scope link 
       valid_lft forever preferred_lft forever
#查看容器内部IP地址。
[[email protected] tomcat]# docker run -d -P --name tomcat01 tomcat
[[email protected] tomcat]# docker exec tomcat01 ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: [email protected]: <NOARP> mtu 1480 qdisc noop state DOWN group default qlen 1000
    link/ipip 0.0.0.0 brd 0.0.0.0
70: [email protected]: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:ac:12:00:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.18.0.2/16 brd 172.18.255.255 scope global eth0
       valid_lft forever preferred_lft forever
#linux可以ping通docker容器
[[email protected] tomcat]# ping 172.18.0.2
PING 172.18.0.2 (172.18.0.2) 56(84) bytes of data.
64 bytes from 172.18.0.2: icmp_seq=1 ttl=64 time=0.098 ms
64 bytes from 172.18.0.2: icmp_seq=2 ttl=64 time=0.047 ms
#2个docker容器之间可以通信
[[email protected] tomcat]# docker run -d -P --name tomcat02 tomcat
7d9fa0f10dffe7d2dea4f9b92030ae82e05b90dd3e6ef7e8dfb563371ac899bc
[[email protected] tomcat]# docker exec -it tomcat02 ping 172.18.0.2
PING 172.18.0.2 (172.18.0.2) 56(84) bytes of data.
64 bytes from 172.18.0.2: icmp_seq=1 ttl=64 time=0.104 ms
64 bytes from 172.18.0.2: icmp_seq=2 ttl=64 time=0.061 ms

–link

[[email protected] tomcat]# docker exec -it tomcat02 ping tomcat01
ping: tomcat01: Name or service not known

[[email protected] tomcat]# docker run -d -P --name tomcat03 --link tomcat02 tomcat
8b0cc29591896a9cb292899148679e5d4db28ce653b94f75b1e59d5350e22c53
[[email protected] tomcat]# docker exec -it tomcat02 ping tomcat03
ping: tomcat03: Name or service not known
[[email protected] tomcat]# docker exec -it tomcat03 ping tomcat02
PING tomcat02 (172.18.0.3) 56(84) bytes of data.
64 bytes from tomcat02 (172.18.0.3): icmp_seq=1 ttl=64 time=0.122 ms
64 bytes from tomcat02 (172.18.0.3): icmp_seq=2 ttl=64 time=0.054 ms
#实际就是在tomcat03的/etc/host文件中写了指向。
[[email protected] tomcat]# docker exec -it tomcat03 cat /etc/hosts
127.0.0.1	localhost
::1	localhost ip6-localhost ip6-loopback
fe00::0	ip6-localnet
ff00::0	ip6-mcastprefix
ff02::1	ip6-allnodes
ff02::2	ip6-allrouters
172.18.0.3	tomcat02 7d9fa0f10dff
172.18.0.4	8b0cc2959189

自定义网络

#查看所有的docker网络
[[email protected] tomcat]# docker network ls
NETWORK ID     NAME      DRIVER    SCOPE
1c3c6040bda4   bridge    bridge    local
e66f66816108   host      host      local
7650407024a8   none      null      local

网络模式
brdige:桥接docker(默认，自定义也使用这个)
none:不配置网络
host:和宿主机共享网络
container:容器内网络连通(用的少,局限性很大)

测试
#我们直接启动的命令 --net bridge，而这个就是docker0
docker run -d -P --name tomcat01 tomcat
docker run -d -P --name tomcat01 tomcat --net bridge tomcat

#docker0特点: 默认域名不能访问。

#自定义网络（推荐使用）

[[email protected] tomcat]# docker network create --driver bridge --subnet 192.168.0.0/16 --gateway 192.168.0.1 mynet
81f91bd3cd41c968c4dc545b2ac9a834f7d33e147fcb391893e4965a4373228e
[[email protected] tomcat]# docker network ls
NETWORK ID     NAME      DRIVER    SCOPE
1c3c6040bda4   bridge    bridge    local
e66f66816108   host      host      local
81f91bd3cd41   mynet     bridge    local
7650407024a8   none      null      local

#测试
[[email protected] tomcat]# docker run -d -P --name tomcat01-net --net mynet tomcat
aaf52f7f541d0950b0feccb7bf6d656c8784d7123efec300a9aa398f76eb38f0
[[email protected] tomcat]# docker run -d -P --name tomcat02-net --net mynet tomcat
c717e6cc63bb12415aaf41f12f77cb9636208854f627061600d359da74662fc7

[[email protected] tomcat]# docker exec -it tomcat01-net ping tomcat02-net
PING tomcat02-net (192.168.0.3) 56(84) bytes of data.
64 bytes from tomcat02-net.mynet (192.168.0.3): icmp_seq=1 ttl=64 time=0.071 ms
64 bytes from tomcat02-net.mynet (192.168.0.3): icmp_seq=2 ttl=64 time=0.074 ms

自定义的网络docker已经帮我们维护好了对应关系。

好处：
redis-不同的集群使用不同的网络，保证集群的安全和健康
mysql-不同的集群使用不同的网络，保证集群的安全和健康

#测试docker0网络中的容器01连接mynet网络中的容器
#将tomcat01添加上mynet网段
[[email protected] tomcat]# docker network connect  mynet tomcat01
[[email protected] tomcat]# docker exec -it tomcat01 ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: [email protected]: <NOARP> mtu 1480 qdisc noop state DOWN group default qlen 1000
    link/ipip 0.0.0.0 brd 0.0.0.0
81: [email protected]: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:ac:12:00:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.18.0.2/16 brd 172.18.255.255 scope global eth0
       valid_lft forever preferred_lft forever
83: [email protected]: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:c0:a8:00:04 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.168.0.4/16 brd 192.168.255.255 scope global eth1
       valid_lft forever preferred_lft forever

[[email protected] tomcat]# docker exec -it tomcat01 ping tomcat02-net
PING tomcat02-net (192.168.0.3) 56(84) bytes of data.
64 bytes from tomcat02-net.mynet (192.168.0.3): icmp_seq=1 ttl=64 time=0.092 ms
64 bytes from tomcat02-net.mynet (192.168.0.3): icmp_seq=2 ttl=64 time=0.068 ms