Why doesn't centos7 include "ip"?

[jamshid]

A lot of linux / centos tutorials mention "ip" as a default utility. But I need to yum install -y iproute when using docker image centos:centos7. Is this intentional?

[alvinchevolleaux]

I think this is a systemd thing and not related to Docker, earlier versions (Centos 6 and below) use the traditional iptables routing mechanisms but Centos 7 uses firewalld.

[jamshid]

Ok thanks, what's the proper centos7 / systemd way to check your IP address (like ip addr show)?

[alvinchevolleaux]

Oh sorry my mistake, I thought you were talking about iptables. If you want to use commands like ip addr show you need to do a yum install. The reason is that the Docker boxes are minimal installations on purpose so as not to add overhead to your environment. In my Dockerfiles I need to include commands such as installing sudo, zip, net-tools, etc. It's also worth noting that you can create your own images with these utilities installed so you don't need to go through these build steps on each deployment.

[jamshid]

Okay, but ip is a command installed on any minimal centos/rhel install. It's in debian, alpine and busybox images. If curl is installed in the centos image (which is nice), seems ip should be too. Yes, I know I can build an image on top of centos, but it's often convenient to not have to.

Thanks for replying, feel free to close this. If you happen to know an alternative to get the ip address of the container without having to yum install, please mention.

[tiangolo]

For those trying to make this work, it installed with yum install iproute. (It wasn't obvious to me what I had to install to have the command ip).

[bcnewlin]

Sorry for the late add, but I just ran into this today myself. I understand that Docker images should be minimal, but ip seems like a strange choice to cut since it is such a basic tool that is almost universally expected to be present.

[tianon]

Apologies for not noticing it sooner, but as noted in the image description (https://hub.docker.com/_/centos/, https://github.com/docker-library/docs/blob/1d3fc2d9de64d104d026b932e957eae3dc5df4ab/centos/README.md#issues), this would be more appropriately filed over in the CentOS bug tracker (https://bugs.centos.org/ or https://github.com/CentOS/sig-cloud-instance-images/issues).

This repository is specifically focused on the documentation of the official images, and the CentOS maintainers do not (at least to my knowlegde) monitor issues filed here. Thanks!

[tchoutri]

@tianon Hi! I'm currently struggling because of the absence of ip or ifconfig.
How am I supposed to make my internet connection work if I cannot configure my interface to to have an IP / gateway so I can use yum… ??
The image assumes that a DHCP server is present on the network and gives an IP, and it makes the image unuseable if it's not the case.

[tianon]

@tchoutri that sounds like it might be a misunderstanding of how networking in Docker usually works, but I'd recommend either the Docker Forums or the Docker Community Slack as better resources for getting help with issues like that 👍

[hervinhio]

This is resolved by yum install -y iproute

[ruddhani]

as an update to @hervinhio what I did in my docker centos 7:

yum date -y

yum install -y net-tools

yum install -y iproute

what I get :

[root@f71060218942 /]# 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
7: eth0@if8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.17.0.2/16 scope global eth0
       valid_lft forever preferred_lft forever

and #cat /etc/sysconfig/iptables-config
showing me the configurations

[jamshid]

The lack of ip (workaround: yum install -y iproute), was mentioned in
CentOS/sig-cloud-instance-images#40
but that project owner did not find it compelling.

So it looks like base centos images will remain ip-less. Crazy.

[h4nek]

For those trying to make this work, it installed with yum install iproute. (It wasn't obvious to me what I had to install to have the command ip).

That worked. It's apt install iproute2 on Ubuntu images btw.