问题:

进入docker容器中，执行命令#ip a查看想看下当前容器的网络状态时候，提示bash: ip: command not found;

解决：

bash: ip: command not found的主要原因是，当前环境下载ubuntu基础镜像只包含简单的操作系统，相当于裸机状态，要想用别的命令需要手动安装。

执行命令：apt-get update & apt-get install -y iproute2

root@153cc0c88ab8:/# apt-get install -y iproute2
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  libatm1 libelf1 libmnl0 libxtables12
Suggested packages:
  iproute2-doc
The following NEW packages will be installed:
  iproute2 libatm1 libelf1 libmnl0 libxtables12
0 upgraded, 5 newly installed, 0 to remove and 35 not upgraded.
Need to get 828 kB of archives.
After this operation, 2587 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 libelf1 amd64 0.170-0.4ubuntu0.1 [44.8 kB]
Get:2 http://archive.ubuntu.com/ubuntu bionic/main amd64 libmnl0 amd64 1.0.4-2 [12.3 kB]
Get:3 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 iproute2 amd64 4.15.0-2ubuntu1.2 [722 kB]
Get:4 http://archive.ubuntu.com/ubuntu bionic/main amd64 libatm1 amd64 1:2.5.1-2build1 [21.9 kB]
Get:5 http://archive.ubuntu.com/ubuntu bionic/main amd64 libxtables12 amd64 1.6.1-2ubuntu2 [27.9 kB]
Fetched 828 kB in 3s (279 kB/s)        
debconf: delaying package configuration, since apt-utils is not installed
Selecting previously unselected package libelf1:amd64.
(Reading database ... 11855 files and directories currently installed.)
Preparing to unpack .../libelf1_0.170-0.4ubuntu0.1_amd64.deb ...
Unpacking libelf1:amd64 (0.170-0.4ubuntu0.1) ...
Selecting previously unselected package libmnl0:amd64.
Preparing to unpack .../libmnl0_1.0.4-2_amd64.deb ...
Unpacking libmnl0:amd64 (1.0.4-2) ...
Selecting previously unselected package iproute2.
Preparing to unpack .../iproute2_4.15.0-2ubuntu1.2_amd64.deb ...
Unpacking iproute2 (4.15.0-2ubuntu1.2) ...
Selecting previously unselected package libatm1:amd64.
Preparing to unpack .../libatm1_1%3a2.5.1-2build1_amd64.deb ...
Unpacking libatm1:amd64 (1:2.5.1-2build1) ...
Selecting previously unselected package libxtables12:amd64.
Preparing to unpack .../libxtables12_1.6.1-2ubuntu2_amd64.deb ...
Unpacking libxtables12:amd64 (1.6.1-2ubuntu2) ...
Setting up libelf1:amd64 (0.170-0.4ubuntu0.1) ...
Processing triggers for libc-bin (2.27-3ubuntu1) ...
Setting up libatm1:amd64 (1:2.5.1-2build1) ...
Setting up libxtables12:amd64 (1.6.1-2ubuntu2) ...
Setting up libmnl0:amd64 (1.0.4-2) ...
Setting up iproute2 (4.15.0-2ubuntu1.2) ...
Processing triggers for libc-bin (2.27-3ubuntu1) ...
root@153cc0c88ab8:/# 
root@153cc0c88ab8:/# ip a
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
21: eth0@if22: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:ac:11:00:03 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.17.0.3/16 brd 172.17.255.255 scope global eth0
       valid_lft forever preferred_lft forever
root@153cc0c88ab8:/#