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How do I stop Docker trying to pull from IPv6? (aussie.zone)
submitted 1 year ago by Zagorath@aussie.zone to c/selfhosted@lemmy.world
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I'm currently trying to install Docker on my old Raspberry Pi (3 Model B+) to host some personal projects. When I run docker run hello-world, I get:

Unable to find image 'hello-world:latest' locally
docker: Error response from daemon: Get "https://registry-1.docker.io/v2/library/hello-world/manifests/sha256:ec153840d1e635ac434fab5e377081f17e0e15afab27beb3f726c3265039cfff": dial tcp [2600:1f18:2148:bc00:eff:d3ae:b836:fa07]:443: connect: network is unreachable

My Internet connection does not support IPv6 at all, which would explain why this error occurs. But how do I force docker-pull to only use IPv4?

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[–] Zagorath@aussie.zone 1 points 1 year ago (1 children)

It’s like if you asked why the top gear in your car isn’t working and gave the model of car and engine type and gearbox

Except if I try and access the same domain using curl, it works fine. For some reason, Docker specifically is what's failing.

[–] tychosmoose@piefed.social 3 points 1 year ago (1 children)

Different programs have different defaults.

But in your situation which would be more helpful - prevent this one docker command from using ipv6 (likely more difficult), or preventing all commands from using your broken ipv6 config (likely easier)?

I have no idea about the first. Maybe some people know this detail. But I'm sure that with a distro and version that you're running, there are lots of people who could help with the second. Raspberry Pi 3B+ is the hardware. What software are you using?

[–] Zagorath@aussie.zone 2 points 1 year ago (1 children)

Whatever the latest version of Raspbian was a month or two ago when I installed it. uname -a outputs [...]6.12.25+rpt-rpi-v8[...]. /etc/os-release contains "Debian GNU/Linux 12 (bookworm)".

[–] tychosmoose@piefed.social 3 points 1 year ago (1 children)

Ok, so it's probably using NetworkManager. I would try disabling it in /etc/NetworkManager/NetworkManager.conf by adding a block like:

[ipv6]
addr-gen-mode=stable-privacy
method=disabled

Then sudo systemctl restart NetworkManager. Can't say for sure if this will work. I dislike using NetworkManager on my servers so I can't test if this works. But hopefully the before/after of ip addr is different.

Although it looks like your ip addr output posted an hour or so ago doesn't show any ipv6 addressing. Maybe the problem is solved now.

[–] Zagorath@aussie.zone 2 points 1 year ago (1 children)

Unfortunately not.

 docker run hello-world
Unable to find image 'hello-world:latest' locally
docker: Error response from daemon: Get "https://registry-1.docker.io/v2/library/hello-world/manifests/sha256:ec153840d1e635ac434fab5e377081f17e0e15afab27beb3f726c3265039cfff": dial tcp [2600:1f18:2148:bc00:eff:d3ae:b836:fa07]:443: connect: network is unreachable

Run 'docker run --help' for more information
[–] tychosmoose@piefed.social 2 points 1 year ago (2 children)

Well crap. Do you have no ipv6 address now in ip addr?

Guess I gave Docker too much benefit of the doubt and assumed it should failover to v4 once v6 was disabled. Bad assumption on my part.

Could it be a DNS problem? If you dig registry-1.docker.io +short does it return an ipv4 or v6 address?

It looks like there have been sporadic reports of problems from people since last year.

[–] Zagorath@aussie.zone 1 points 1 year ago (1 children)

Do you have no ipv6 address now in ip addr

Just comparing it by eye, there's no change.

zag@raspberrypi:~ $ man dig
No manual entry for dig
zag@raspberrypi:~ $ which dig
zag@raspberrypi:~ $ sudo apt install dig
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
E: Unable to locate package dig

But if I ping it

$ ping registry-1.docker.io
PING registry-1.docker.io (107.20.112.188) 56(84) bytes of data.
[–] tychosmoose@piefed.social 2 points 1 year ago (1 children)

It's in the dnsutils package.

[–] Zagorath@aussie.zone 1 points 1 year ago 
52.207.69.161
52.21.128.203
3.224.238.37
44.218.153.24
54.210.249.78
18.232.25.125
52.72.195.97
54.161.169.181
[–] MysteriousSophon21@lemmy.world 1 points 1 year ago (1 children)

Try adding {"ipv6": false} to your /etc/docker/daemon.json file (create it if it doesnt exist), then restart docker with sudo systemctl restart docker - this forces docker to use IPv4 only.

[–] tychosmoose@piefed.social 1 points 1 year ago

This flag seems to only disable ipv6 on the default Docker bridge network, not daemon-wide. At least per this discussion.