《2021/07/24》1 -- linux -- 网络名称空间和网桥的基本操作

最新推荐文章于 2024-12-25 00:16:34 发布

guo_xiaozhong

最新推荐文章于 2024-12-25 00:16:34 发布

阅读量312

点赞数

分类专栏： Docker学习

原文链接：https://www.cnblogs.com/GH-123/p/10230869.html

版权

Docker学习专栏收录该内容

7 篇文章

订阅专栏

本文详细介绍了Linux系统中如何进行网络名称空间（NETNamespace）的创建与管理，包括查看、添加和删除网络名称空间，以及通过veth对创建虚拟网卡并进行命名空间之间的通信。同时，文章探讨了网桥的建立与配置，解释了如何将网卡设备添加到网桥，以及在遇到通信问题时如何解决，展示了如何通过调整路由设置实现名称空间间的正常通信。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

网络名称空间和网桥的基本操作

网络命名空间和网桥的基本操作命令

网络名称空间 (NET Namespace)

查看是否有iproute

[root@localhost ~]# rpm -q iproute
iproute-4.11.0-14.el7.x86_64

创建n1, n2 网络名称空间

[root@localhost ~]# ip netns add n1
[root@localhost ~]# ip netns add n2

这种方式创建只有网络名称空间是独立的, 其他名称空间不是独立的。

查看网络名称空间

[root@localhost ~]# ip netns list
n2
n1

n1网络空间里执行查看网卡接口命令

[root@localhost ~]# ip netns exec n1 ifconfig -a
lo: flags=8<LOOPBACK>  mtu 65536
        loop  txqueuelen 1000  (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

创建两个以太网网卡对并查看设备

[root@localhost ~]# ip link add name veth1.1 type veth peer name veth1.2
[root@localhost ~]# ip link show | grep 'veth'
13: veth1.2@veth1.1: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
14: veth1.1@veth1.2: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000

把veth1.2放到n1里

[root@localhost ~]# ip link set dev veth1.2 netns n1
[root@localhost ~]# ip link show | grep 'veth'
14: veth1.1@if13: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000

查看n1

[root@localhost ~]# ip netns exec n1 ifconfig -a | grep 'veth'
veth1.2: flags=4098<BROADCAST,MULTICAST>  mtu 1500

在n1把veth1.2改成eth0

[root@localhost ~]# ip netns exec n1 ip link set dev veth1.2 name eth0
[root@localhost ~]# ip netns exec n1 ifconfig -a | grep 'veth'
[root@localhost ~]# ip netns exec n1 ifconfig -a | grep 'eth0'
eth0: flags=4098<BROADCAST,MULTICAST>  mtu 1500

启动veth1.1并赋予IP

[root@localhost ~]# ifconfig -a | grep 'veth'
veth1.1: flags=4098<BROADCAST,MULTICAST>  mtu 1500
[root@localhost ~]# ifconfig veth1.1 10.1.0.1/24 up
[root@localhost ~]# ifconfig -a | grep 'veth'
veth1.1: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500

把n1里的也启动并赋予IP

[root@localhost ~]# ip netns exec n1 ifconfig eth0 10.1.0.2/24 up
[root@localhost ~]# ip netns exec n1 ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.1.0.2  netmask 255.255.255.0  broadcast 10.1.0.255
        inet6 fe80::a0dd:c4ff:fe13:38f0  prefixlen 64  scopeid 0x20<link>
        ether a2:dd:c4:13:38:f0  txqueuelen 1000  (Ethernet)
        RX packets 8  bytes 648 (648.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 8  bytes 648 (648.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

主机和n1通信

[root@localhost ~]# ping -c3 10.1.0.2
PING 10.1.0.2 (10.1.0.2) 56(84) bytes of data.
64 bytes from 10.1.0.2: icmp_seq=1 ttl=64 time=0.075 ms
64 bytes from 10.1.0.2: icmp_seq=2 ttl=64 time=0.038 ms
64 bytes from 10.1.0.2: icmp_seq=3 ttl=64 time=0.041 ms

--- 10.1.0.2 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2001ms
rtt min/avg/max/mdev = 0.038/0.051/0.075/0.017 ms

把veth1.1放到n2

[root@localhost ~]# ip link set dev veth1.1 netns n2
[root@localhost ~]# ip netns exec n2 ifconfig veth1.1 10.1.0.1/24 up
[root@localhost ~]# ip netns exec n2 ifconfig
veth1.1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.1.0.1  netmask 255.255.255.0  broadcast 10.1.0.255
        inet6 fe80::1097:c8ff:fe37:2e36  prefixlen 64  scopeid 0x20<link>
        ether 12:97:c8:37:2e:36  txqueuelen 1000  (Ethernet)
        RX packets 13  bytes 1026 (1.0 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 21  bytes 1674 (1.6 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

n2通信n1

[root@localhost ~]# ip netns exec n2 ping -c3 10.1.0.2
PING 10.1.0.2 (10.1.0.2) 56(84) bytes of data.
64 bytes from 10.1.0.2: icmp_seq=1 ttl=64 time=0.102 ms
64 bytes from 10.1.0.2: icmp_seq=2 ttl=64 time=0.037 ms
64 bytes from 10.1.0.2: icmp_seq=3 ttl=64 time=0.038 ms

--- 10.1.0.2 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 0.037/0.059/0.102/0.030 ms

主机通信n1或者n2都不通

网桥

创建br0网桥并启动

[root@localhost ~]# ip link add name br0 type bridge
[root@localhost ~]# ip link set br0 up
[root@localhost ~]# ifconfig br0
br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet6 fe80::463:74ff:fe4c:10cf  prefixlen 64  scopeid 0x20<link>
        ether 06:63:74:4c:10:cf  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 6  bytes 508 (508.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

创建以太网(veth)类型的网卡对 veth0 和 veth1

[root@localhost ~]# ip link add veth0 type veth peer name veth1
[root@localhost ~]# ip addr add 10.20.1.10/24 dev veth0
[root@localhost ~]# ip link set veth0 up
[root@localhost ~]# ifconfig | grep -A 2 'veth'
veth0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 10.20.1.10  netmask 255.255.255.0  broadcast 0.0.0.0
        ether d6:b7:5a:b2:5b:a6  txqueuelen 1000  (Ethernet)

创建ns1网络名称空间并把veth1加入

[root@localhost ~]# ip netns add ns1
[root@localhost ~]# ip link set dev veth1 netns ns1
[root@localhost ~]# ip netns exec ns1 ip addr add 10.20.1.20/24 dev veth1
[root@localhost ~]# ip netns exec ns1 ip link set veth1 up
[root@localhost ~]# ip netns exec ns1 ifconfig
veth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.20.1.20  netmask 255.255.255.0  broadcast 0.0.0.0
        inet6 fe80::e018:ebff:fe42:18df  prefixlen 64  scopeid 0x20<link>
        ether e2:18:eb:42:18:df  txqueuelen 1000  (Ethernet)
        RX packets 8  bytes 648 (648.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 8  bytes 648 (648.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

veth0和veth1通信成功

[root@localhost ~]# ping -c1 10.20.1.20
PING 10.20.1.20 (10.20.1.20) 56(84) bytes of data.
64 bytes from 10.20.1.20: icmp_seq=1 ttl=64 time=0.056 ms

--- 10.20.1.20 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.056/0.056/0.056/0.000 ms

把veth0连接上网桥br0

[root@localhost ~]# ip link set dev veth0 master br0
[root@localhost ~]# bridge link
17: veth0 state UP @(null): <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master br0 state forwarding priority 32 cost 2

此时br0的mac地址为veth0的mac地址且veth0不再转发数据给内核（协议栈），而是br0来转发。

veth0和veth1通信失败

[root@localhost ~]# ping -c1 10.20.1.20
PING 10.20.1.20 (10.20.1.20) 56(84) bytes of data.

--- 10.20.1.20 ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

给br0配置ip来转发数据给内核（协议栈），接着通信还是失败

[root@localhost ~]# ip addr add 10.20.1.15/24 dev br0
[root@localhost ~]# ifconfig br0
br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.20.1.15  netmask 255.255.255.0  broadcast 0.0.0.0
        inet6 fe80::463:74ff:fe4c:10cf  prefixlen 64  scopeid 0x20<link>
        ether d6:b7:5a:b2:5b:a6  txqueuelen 1000  (Ethernet)
        RX packets 5  bytes 196 (196.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 8  bytes 648 (648.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@localhost ~]# ping -c1 10.20.1.20
PING 10.20.1.20 (10.20.1.20) 56(84) bytes of data.
From 10.20.1.10 icmp_seq=1 Destination Host Unreachable

--- 10.20.1.20 ping statistics ---
1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms

删除veth0的默认路由，接着通信成功

[root@localhost ~]# ip route show | grep '10.20.1.0'
10.20.1.0/24 dev veth0 proto kernel scope link src 10.20.1.10
10.20.1.0/24 dev br0 proto kernel scope link src 10.20.1.15
[root@localhost ~]# ip route del 10.20.1.0/24 dev veth0
[root@localhost ~]# ip route show | grep '10.20.1.0'
10.20.1.0/24 dev br0 proto kernel scope link src 10.20.1.15
[root@localhost ~]# ping -c1 10.20.1.20
PING 10.20.1.20 (10.20.1.20) 56(84) bytes of data.
64 bytes from 10.20.1.20: icmp_seq=1 ttl=64 time=0.062 ms

--- 10.20.1.20 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.062/0.062/0.062/0.000 ms