容器网络之 veth设备

创建命名空间

# ip netns add mhc

# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000
    link/ether dc:fe:07:d6:10:67 brd ff:ff:ff:ff:ff:ff
3: wlp2s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DORMANT qlen 1000
    link/ether 2a:3d:4b:78:d6:34 brd ff:ff:ff:ff:ff:ff
4: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT qlen 1000
    link/ether 52:54:00:ea:e7:08 brd ff:ff:ff:ff:ff:ff
5: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN mode DEFAULT qlen 1000
    link/ether 52:54:00:ea:e7:08 brd ff:ff:ff:ff:ff:ff
6: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT
    link/ether 02:42:f1:10:e3:bc brd ff:ff:ff:ff:ff:ff
10: veth879059f@if9: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP mode DEFAULT
    link/ether f2:5a:39:f5:94:63 brd ff:ff:ff:ff:ff:ff link-netnsid 0

# ip netns exec mhc ip link show
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULT qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

添加一对veth设备

ip link add veth0 type veth peer name veth1

# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000
    link/ether dc:fe:07:d6:10:67 brd ff:ff:ff:ff:ff:ff
3: wlp2s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DORMANT qlen 1000
    link/ether be:6d:49:a4:79:2e brd ff:ff:ff:ff:ff:ff
4: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT qlen 1000
    link/ether 52:54:00:ea:e7:08 brd ff:ff:ff:ff:ff:ff
5: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN mode DEFAULT qlen 1000
    link/ether 52:54:00:ea:e7:08 brd ff:ff:ff:ff:ff:ff
6: docker0: <BROADCAST,MUL# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000
    link/ether dc:fe:07:d6:10:67 brd ff:ff:ff:ff:ff:ff
3: wlp2s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DORMANT qlen 1000
    link/ether be:6d:49:a4:79:2e brd ff:ff:ff:ff:ff:ff
4: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT qlen 1000
    link/ether 52:54:00:ea:e7:08 brd ff:ff:ff:ff:ff:ff
5: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN mode DEFAULT qlen 1000
    link/ether 52:54:00:ea:e7:08 brd ff:ff:ff:ff:ff:ff
6: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT
    link/ether 02:42:f1:10:e3:bc brd ff:ff:ff:ff:ff:ff
10: veth879059f@if9: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP mode DEFAULT
    link/ether f2:5a:39:f5:94:63 brd ff:ff:ff:ff:ff:ff link-netnsid 0
27: veth1@veth0: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000
    link/ether 82:72:ea:99:16:2c brd ff:ff:ff:ff:ff:ff
28: veth0@veth1: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000
    link/ether 56:44:ef:da:0f:42 brd ff:ff:ff:ff:ff:ff

TICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT
    link/ether 02:42:f1:10:e3:bc brd ff:ff:ff:ff:ff:ff
10: veth879059f@if9: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP mode DEFAULT
    link/ether f2:5a:39:f5:94:63 brd ff:ff:ff:ff:ff:ff link-netnsid 0
27: veth1@veth0: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000
    link/ether 82:72:ea:99:16:2c brd ff:ff:ff:ff:ff:ff
28: veth0@veth1: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000
    link/ether 56:44:ef:da:0f:42 brd ff:ff:ff:ff:ff:ff

将veht1 移到另一个namespace

ip link set veth1 netns mhc

# ip netns exec mhc ip link show
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULT qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
27: veth1@if28: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000
    link/ether 82:72:ea:99:16:2c brd ff:ff:ff:ff:ff:ff link-netnsid 0

设置ip地址

# ip netns exec mhc ip addr add 10.1.1.1/24 dev veth1

# ip addr add 10.1.1.2/24 dev veth0

启用设备

# ip netns exec mhc ip link set dev veth1 up

# ip link set dev veth0 up

# ping 10.1.1.1
PING 10.1.1.1 (10.1.1.1) 56(84) bytes of data.
64 bytes from 10.1.1.1: icmp_seq=1 ttl=64 time=0.065 ms
64 bytes from 10.1.1.1: icmp_seq=2 ttl=64 time=0.076 ms

# ip netns exec mhc ping 10.1.1.2
PING 10.1.1.2 (10.1.1.2) 56(84) bytes of data.
64 bytes from 10.1.1.2: icmp_seq=1 ttl=64 time=0.088 ms
64 bytes from 10.1.1.2: icmp_seq=2 ttl=64 time=0.040 ms

如何查看对端

# ethtool -S veth0
NIC statistics:
     peer_ifindex: 27

# ip netns exec mhc ip link|grep 27
27: veth1@if28: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT qlen 1000

删除veth设备(同时在另一个nemespace的设备也被删除了)

# ip link delete veth0

删除网络命名空间

# ip netns ls
mhc (id: 1)
# ip netns delete mhc