Namespace Flow Example

This example runs a single-host namespace workload where the controller and Postgres run in Docker, and one local dataplane process spawns many namespace nodes and flow senders.

Linux prerequisites

• Linux host with iproute2 (ip command), sudo, and tmux.
• Docker Engine with docker compose (or docker-compose fallback).
• python3 (used by examples/ns-flow/generate.py).
• Rust toolchain (cargo) unless you already have a built nextmini binary.

Namespace-specific behavior from this example:

• examples/ns-flow/run.sh applies Linux sysctl tuning for large namespace/veth churn.
• examples/ns-flow/generate.py writes examples/ns-flow/controller-config.toml and examples/ns-flow/config.toml.
• Generated dataplane config sets enable_local_interface = false for namespace flow runs.

1. Generate config files

From the repository root, generate the default 136-node / 180-flow configuration:

python3 examples/ns-flow/generate.py --n-nodes 136 --n-flows 180 --src 1 --dst 136

To customize the workload, pass the same arguments that run.sh accepts:

python3 examples/ns-flow/generate.py \
  --n-nodes 200 \
  --n-flows 400 \
  --src 1 \
  --dst 200 \
  --flow-bytes 1000000 \
  --flow-rate 500000 \
  --flow-weight 1

run.sh regenerates these files automatically unless you pass --no-generate.

2. Start the example

Start everything with the orchestration script:

sudo ./examples/ns-flow/run.sh

run.sh orchestration details:

1. Applies sysctl tuning (unless --no-sysctl).
2. Regenerates config files (unless --no-generate).
3. Starts a tmux session (nextmini-ns-flow) with:
   • left pane: docker compose up --build in examples/ns-flow
   • right pane: build dataplane (if needed), wait for Postgres/controller readiness, then launch nextmini with examples/ns-flow/config.toml

If you only want tuning without startup:

sudo ./examples/ns-flow/run.sh --sysctl-only

3. Verify startup and flow completion

Check generated counts:

grep -c '^\[\[routes\]\]' examples/ns-flow/controller-config.toml
grep -c '^\[\[flows\]\]' examples/ns-flow/controller-config.toml

Check seeded and finished flows in Postgres:

docker exec postgres psql -U pgusr -d nextmini -c \
  "SELECT COUNT(*) AS total, COUNT(*) FILTER (WHERE is_finished) AS finished FROM flows;"

Optional route sanity check:

docker exec postgres psql -U pgusr -d nextmini -c "SELECT COUNT(*) AS routes FROM routes;"

4. Cleanup

Stop tmux/docker and remove created namespace networking artifacts:

sudo ./examples/ns-flow/cleanup.sh

The cleanup script kills the nextmini-ns-flow tmux session, brings down examples/ns-flow/docker-compose.yml, deletes veth* links for configured nodes, and removes isobr* bridge shards.