mknet/README.md

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# mknet
mknet is a tool to simulate various network topologies
locally thanks to network namespaces and traffic control (tc).
## Prepare your environment
Get the repository:
```bash
git clone https://git.deuxfleurs.fr/Deuxfleurs/mknet.git
cd mknet
```
Run our configuration script:
```bash
./prepare.py
```
Now, you are ready to launch an experiment:
```bash
sudo -i
source .venv/bin/activate
./mknet scenario ./topo/50ms.yml ./scenarios/garage-s3lat garage-v0.8
```
## Topologies
All topologies:
- `./topo/with-vdsl.yml` - A topology mixing datacenters with fast internal connectivity and an isolated VDSL node
- `./topo/50ms.yml` - An artifical topology simulating nodes with high bandwidth but with a fixed 50ms latency, useful to quantify the impact of latency on a distributed software
- `./topo/multi-dc.yml` - Simulate 3 DC interconnected with 50ms latency WAN network and close to zero latency inside the DC
- `./topo/slow.yml` - Simulate 3 nodes interconnected with a low latency, very low bandwidth link. Useful to debug bandwidth bottlenecks
Feel free to write new topologies!
## Scenarios
All scenarios:
- `./scenarios/garage-s3lat [garage-v0.7|garage-v0.8]` - Run s3lat on Garage
- `./scenarios/garage-warp [garage-v0.7|garage-v0.8] [default|fast]` - Run warp on Garage. 2 flavors are available: fast and default.
*Scenarios take optional flavors as input that modulate their behavioir. Passing them is not mandatory,
a default one will be selected for you.*
How to run them:
```bash
./mknet scenario <topology> <scenario> [flavors...]
./mknet scenario ./topo/50ms.yml ./scenarios/garage-s3lat garage-v0.8
```
How to write good scenarios:
- If a scenario can be run with multiple different parameters, write one scenario with multiple flavors
- If the logic ran is different, write a new scenario
- A scenario code must remain short and looks like a DSL, abstract the logic in the `fragments/` module
## Manual usage
```bash
./mknet create ./topo/with-vdsl.yml
./mknet run-all ./scenarios/garage-manual
./mknet run dc1:dc1s1 /tmp/mknet-bin/garage* -c /tmp/mknet-store/garage/dc1/dc1s1/garage.toml status
./mknet run-all ./scenarios/clean
./mknet destroy