[WSL 2] Multi WSL2 distributions use the same network namespace

[prabhah]

Issue

Multi WSL2 distributions use the same network namespace, no network isolation

Issue Details

• Your Windows build number: Microsoft Windows [版本 10.0.18936.1000]

• What you're doing and what's happening:

1. wsl --list -v
   NAME STATE VERSION
   Ubuntu-16.04 Running 2
   Ubuntu-16.04-b Running 2
   centos Running 2

2. In Ubuntu-16.04 / Ubuntu-16.04-b / centos, the eth0 has the same IP
   root@DESKTOP-ASI6ES4:~$ ifconfig eth0 | grep "inet addr"
   inet addr: 172.30.114.66 Bcast:172.30.255.255 Mask:255.255.0.0

   It seems that all the distributions share the same network namespace
   Start a webserver on two distributions:
   python3 -m http.server 8000,
   the second distribution will get failed:

root@DESKTOP-ASI6ES4:/chesstop/log# python3 -m http.server 8000 Traceback (most recent call last): File "/usr/lib/python3.5/runpy.py", line 184, in _run_module_as_main "__main__", mod_spec) File "/usr/lib/python3.5/runpy.py", line 85, in _run_code exec(code, run_globals) File "/usr/lib/python3.5/http/server.py", line 1221, in <module> test(HandlerClass=handler_class, port=args.port, bind=args.bind) File "/usr/lib/python3.5/http/server.py", line 1194, in test httpd = ServerClass(server_address, HandlerClass) File "/usr/lib/python3.5/socketserver.py", line 440, in __init__ self.server_bind() File "/usr/lib/python3.5/http/server.py", line 138, in server_bind socketserver.TCPServer.server_bind(self) File "/usr/lib/python3.5/socketserver.py", line 454, in server_bind self.socket.bind(self.server_address) OSError: [Errno 98] Address already in use

• What's wrong / what should be happening instead:
  Each distribution should have its own network namespace

[craigloewen-msft]

This is done by design, and so I'll mark this issue as closed, but am more than happy to follow up on a discussion about it.

What scenario are you trying to enable by having the distributions have different networking namespaces?

[prabhah]

This is done by design, and so I'll mark this issue as closed, but am more than happy to follow up on a discussion about it.

What scenario are you trying to enable by having the distributions have different networking namespaces?

Thanks for your response. I think WSL/WSL2 is a great feature for microsoft product. I'd like to try it in our work environment.
We develop cluster softwares which works on more that one node, we use virtualbox / vmware ... to setup our development environment before, but these virtual technologies are too heavy for development machine. if WLS2 support network isolation, we can use this lightweight virtual techonlogy to achieve our purpose.

[craigloewen-msft]

You can create new processes with new network namespaces, so yes you can achieve network isolation.

[prabhah]

You can create new processes with new network namespaces, so yes you can achieve network isolation.

thanks for reminding me,

`
ip netns add net1

ip netns exec net1 ip addr add 192.168.99.10/24 dev sit0

ip netns exec net1 exec bash
...
`
you mean this?
Great Idea :) but it's indirectly way

[craigloewen-msft]

Yes that's exactly correct!

And to check my understanding, you're asking that you'd prefer each distro was in its own networking namespace rather than creating your own network namespaces, because it would be a more direct way? Or easier to setup? I'm sorry as I'm still confused on the feature request, or what you're asking.

[prabhah]

English is not my native language, sorry for my imprecision description to make you confuse.
At the beginning of the problem，after I created multi WSL2 instances/distros, I found they used the same IP, I guess that they share the same network namespace.
I just want to create a multi-nodes development environment, eath instance/distro have their own IP.
Thanks for your help again.

[craigloewen-msft]

No problem at all! Thank you for clarifying.

All of the WSL 2 distros run on the same virtual machine, which has a singular virtualized networking interface controller. You can create different IP addresses and different networking namespaces just like you would on a Linux machine to create network isolation for multi-node development.

[cpbotha]

When using multiple WSL2 distros in parallel, it would have been useful to be able to SSH into any one of them by using different IP numbers. (Personally I use this to manage git repos from Emacs magit running on WSL1 or on Windows native, via TRAMP over ssh.)

As it stands, one either has to run the ssh daemons on different ports, or, IIUC, setup namespaces within each WSL2 distro and have the relevant daemon processes (e.g. ssh) attaching to those.

See e.g. https://blogs.igalia.com/dpino/2016/04/10/network-namespaces/ -- setup looks like it could cost some time.

Bottom-line: A more straight-forward, out-of-the-box mechanism whereby different WSL2 distros could be approached via network would be valuable.

[smeierhofer]

If you want to run an SSH server on each WSL distro, could you follow the steps in the link posted by @craigloewen-msft to assign additional IP addresses to the network interface card? Then configure the SSH server to bind to only the one IP address (not sure how to do this but I'm sure this is doable). On your 2nd WSL distro you do the same, but configure the SSH server to bind to a different IP address. Then probably you want to add entries into your host file for the IP addresses and then you can SSH into these distros using the hostname you've given in your hosts file. I haven't tried this myself but if it work, it is better way to go than using CGROUPS (networking namespaces) to run an SSH server on each distro. The network namespaces approach seems a better for problems where you want the same IP address but want to isolate more than just use a new IP address or port number.

[fzhan]

I guess by 2022, no one has tried to create three nodes microk8s cluster via WSL2?

Could turn Windows in to a beast.

[ismailokta]

yes I agree, At first, I was happy with WSL2, which is lighter than using virtualbox, it has library isolation, but the network doesn't. really bear it

[fl0wm0ti0n]

i want to scp files to one of my wsl instances but that isn't possible because they have all the same ip address and the address isn't reachable over network... if wsl cant have its own reachable ip its a bit useless sometimes :(

debian -> 172.27.246.30
debiandev01 -> 172.27.246.30

and "wsl hostname -i" gives for both 127.0.1.1 ...

is it possible to have a reachable ipaddress?

[Biswa96]

Instead of using network, wouldn't it be possible to use shared mount points, for example, /mnt/wsl or /mnt/wslg ?

Also it is possible to mount one distribution to another, both are running. I forgot the exact name of that feature.

[jmenashe]

Why in the world is this closed? The whole point of a virtual machine is to facilitate isolation. Sharing a network interface is the opposite of isolation. Or has the problem already been resolved in some way?

[mwoodpatrick]

I think an option for assigning a different IP address to a distro is an interesting area of discussion its a shame that it was closed though I understand why a single network for all distro's is the default it would be good to have this as a configuration option. It would be good if someone has the actual link posted by craigloewen-msft on assigning additional IP addresses to the network interface card.

[foxhacker0000]

by our friend way i can make new ip for my machine but this ip will work for all distro(s) :///

making new ip for eth0 interface will not isolate the network.

yes it will work but cannot fix my problem
i dont need to add additional ip for my wsl network

i want to full isolate network

[volcano621]

Agree. Full isolate network is needed.