本机ip突然连不上数据库（docker网桥网段覆盖了本机网段）

超、凢脫俗 2022-10-05 13:46 159阅读 0赞

今天收到报警，有一台服务器权限错误，排查得知，服务器ping不通数据库了，两者连接不上了

[root@test002 ~]# ping rm-XXXXXXXXXXXX.mysql.rds.aliyuncs.com
    PING rm-XXXXXXXXXXXX.mysql.rds.aliyuncs.com (172.17.0.232) 56(84) bytes of data.
    From test002 (172.17.0.1) icmp_seq=1 Destination Host Unreachable
    From test002 (172.17.0.1) icmp_seq=2 Destination Host Unreachable
    From test002 (172.17.0.1) icmp_seq=3 Destination Host Unreachable

Destination Host Unreachable 目标主机不能到达  
不过看这个ip有点奇怪，服务器通用是16网段，怎么ip变成17了  
查看ip

[root@test002 ~]# ip a
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
        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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
        link/ether 00:33:3e:aa:d5:35 brd ff:ff:ff:ff:ff:ff
        inet 172.16.128.2/24 brd 172.16.128.255 scope global eth0
           valid_lft forever preferred_lft forever
    3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP 
        link/ether 02:42:95:2e:15:8b brd ff:ff:ff:ff:ff:ff
        inet 172.17.0.1/16 scope global docker0
           valid_lft forever preferred_lft forever

docker网桥的ip段把本机ip段覆盖了，而docker的默认网段172.17网段和数据库网段冲突了  
把docker的ip段关闭就好了

ip link set dev docker0  down

重新查看ip

[root@test002 ~]# ip a
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
        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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
        link/ether 00:33:3e:aa:d5:35 brd ff:ff:ff:ff:ff:ff
        inet 172.16.128.2/24 brd 172.16.128.255 scope global eth0
           valid_lft forever preferred_lft forever
    3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state DOWN
        link/ether 02:42:95:2e:15:8b brd ff:ff:ff:ff:ff:ff
        inet 172.17.0.1/16 scope global docker0
           valid_lft forever preferred_lft forever

可以看到docker那显示 state DOWN  
重新ping数据库

[root@test002 ~]# ping rm-XXXXXXXXXXXX.mysql.rds.aliyuncs.com
    PING rm-XXXXXXXXXXXX.mysql.rds.aliyuncs.com (172.17.0.232) 56(84) bytes of data.
    64 bytes from 172.17.0.232 (172.17.0.232): icmp_seq=1 ttl=102 time=0.686 ms

服务正常了

最好更换一下docker网段  
替换后，重新ping数据库也是正常的，docker也能正常使用了