Arch Linux

yper

Member

Registered: 2021-04-12

Posts: 2

Fresh Docker install not giving containers access to internet

Hello Everybody,

I'm a long ago linux user who is attempting a comeback after ~15 years. I have a newly built PC onto which I've successfully installed Arch a few days ago `Linux 5.11.12-arch1-1`.

I then proceeded to install docker:

sudo pacman -S docker

start it and set up to start on boot:

sudo systemctl enable docker && sudo systemctl start docker

giving user access to run docker commands:

sudo usermod -aG docker $USER

Now to the problem, None of the docker containers I run get access to the internet:

> docker run --rm alpine:latest ping -c 2 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes

--- 8.8.8.8 ping statistics ---
2 packets transmitted, 0 packets received, 100% packet loss

if I add "--network=host" to the command it works:

> docker run --network=host --rm alpine:latest ping -c 2 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: seq=0 ttl=115 time=112.946 ms
64 bytes from 8.8.8.8: seq=1 ttl=115 time=48.652 ms

--- 8.8.8.8 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 48.652/80.799/112.946 ms

checking with a colleage of mine who also runs linux it seems his IPtables get added to when starting a container, something that does not happen on my machine.

Things I've tried, with no change in behaviour

1. docker run using sudo

2. add IPForward=kernel to /usr/lib/systemd/network/80-container-host0.network

3. add IPForward=true to /usr/lib/systemd/network/80-container-host0.network

4. add IPForward=yes to /usr/lib/systemd/network/80-container-host0.network

5. remove docker, reboot, reinstall docker, reboot, try again.

docker has created an interface and it is unmanaged:

> networkctl list
IDX LINK    TYPE     OPERATIONAL SETUP
  1 lo      loopback carrier     unmanaged
  2 enp2s0  ether    routable    configured
  3 docker0 bridge   no-carrier  unmanaged

IP of docker0:

> ip a | grep docker0
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0

even accessing the docker gateway from within the conatiner seems to work:

> docker run --rm alpine:latest traceroute 172.12.0.1
traceroute to 172.12.0.1 (172.12.0.1), 30 hops max, 46 byte packets
 1  e28faddc9998 (172.17.0.2)  3035.917 ms !H  3039.730 ms !H  3040.023 ms !H

I've read every thread I thins I can find and perplexed what is causing this
any help much apprechiated

LegacyRequirements

Member

Registered: 2021-04-19

Posts: 2

Re: Fresh Docker install not giving containers access to internet

I'm experiencing this issue as well. I've done some troubleshooting and while I don't have much to add I can confirm that I'm not seeing any traffic on either the veth device for the container, nor the docker0 bridge:

> docker run --rm alpine:latest ping 8.8.8.8 

> sudo tcpdump -i docker0

The only traffic over the veth device is some ARP requests

  > sudo tcpdump -i veth08362b1
  10:32:05.662476 ARP, Request who-has 172.17.0.1 tell 172.17.0.2, length 28
  10:32:07.638418 ARP, Request who-has 172.17.0.1 tell 172.17.0.2, length 28
  10:32:08.649082 ARP, Request who-has 172.17.0.1 tell 172.17.0.2, length 28
  10:32:09.662411 ARP, Request who-has 172.17.0.1 tell 172.17.0.2, length 28

Last edited by LegacyRequirements (2021-04-19 10:35:44)

yper

Member

Registered: 2021-04-12

Posts: 2

Re: Fresh Docker install not giving containers access to internet

Afraid I was unable to find any solution to this. and evenutally resorted to a re-install without using the new installer script and going with ext4 instead of btrfs as my filesystem (I doubt this had anything to do with it).

after that my system started to behave as expected and docker has no issues anymore.

Sorry I'm unable to help.

A friend of mine tried to update to see if it was a docker/kernel issue but his system continuted to work as it did before.. so that does not seem to be it.

Did you use the 04.01 installer script?

Morn

Member

Registered: 2012-09-02

Posts: 886

Re: Fresh Docker install not giving containers access to internet

Afraid I was unable to find any solution to this. and evenutally resorted to a re-install without using the new installer script and going with ext4 instead of btrfs as my filesystem (I doubt this had anything to do with it).

Perhaps not, but still a much better decision for system health than using this experimental, unproven new installer and crappy btrfs filesystem.

LegacyRequirements

Member

Registered: 2021-04-19

Posts: 2

Re: Fresh Docker install not giving containers access to internet

Afraid I was unable to find any solution to this. and evenutally resorted to a re-install without using the new installer script and going with ext4 instead of btrfs as my filesystem (I doubt this had anything to do with it).

after that my system started to behave as expected and docker has no issues anymore.

Sorry I'm unable to help.

A friend of mine tried to update to see if it was a docker/kernel issue but his system continuted to work as it did before.. so that does not seem to be it.

Did you use the 04.01 installer script?

Yeah, unfortunately Arch doesn't lend itself to bootstrapping a new OS quickly and sometimes that's what you've got to do. I didn't use BTFS, but I did use the installer. Oh well.

chuenjin

Member

Registered: 2021-04-21

Posts: 1

Re: Fresh Docker install not giving containers access to internet

FWIW, I also had this issue after installing with archinstall.  A second manual reinstall didn't fix it for me however.  I tried a third install, this time using the latest version of archinstall from the github repo (2.1.4) and using Network Manager rather than systemd-networkd as I had on the first two installs, and it worked for me.