WSL subnet utility
This is a small Go utility to set the WSL2 host and subnet. It achieves this by:
- deleting the existing WSL network
- creating a new one with the specified subnet (defaulting to
192.168.100.0/24)
Windows automatically creates the WSL network when a WSL2 environment is started, so we need to pre-empt this by creating our own network with our settings before that happens.
Important notes
- this needs to be done before starting any WSL2 (or Docker on WSL2) environments
- if you need to do this afterwards, restart WSL2 environments by shutting them down with
wsl --shutdown; they should work correctly after they're re-launched. - you may need to disable Docker auto-start: this needs to run first
- the utility needs to be run in an elevated mode (administrator) in order to alter the network configuration
- you'll get an
Access deniederror if you are not elevated - run in an elevated console
- or schedule as a task (noted below)
- you'll get an
Basic command line help can be obtained with wsl-subnet --help
Installing this as a task is possible via the Task Scheduler:
- Use
At system startupas the trigger - Run under the
SYSTEMaccount
Build
cd src
go build .
This will yield a single, static executable: wsl-subnet.exe
References and acknowledgements
We're making use the Windows Host Compute Network interfaces to do this:
- https://docs.microsoft.com/en-us/windows-server/networking/technologies/hcn/hcn-declaration-handles
- https://docs.microsoft.com/en-us/windows-server/networking/technologies/hcn/hcn-json-document-schemas
Fortunately, Microsoft has supplied the hcsshim Go library to interact with these interfaces at a higher level. This library is used by various projects, including (at some stage), Docker itself.
This is a simple utility inspired partly by the various Powershell scripts out there to control WSL booting and subnet assignment, including:
- https://github.com/ocroz/wsl2-boot
- https://github.com/skorhone/wsl2-custom-network
- https://github.com/jgregmac/hyperv-fix-for-devs
- https://github.com/wikiped/WSL-IpHandler
Check those out if you need something more complex.
