maint: fix load test (#148)

## Which problem is this PR solving?

The Service "echoserver" is invalid: spec.type: Unsupported value:
"LoadBalancers": supported values: "ClusterIP", "ExternalName",
"LoadBalancer", "NodePort"

## Short description of the changes

- Fix typo on LoadBalancers to be LoadBalancer
- Add make targets for easy load testing
- Add notes to `DEVELOPING.md` doc for load testing
- Add `.gitignore` for temp locust file

## How to verify that this has the expected result

Follow notes in `DEVELOPING.md` for successful load testing

```sh
make docker-build
make loadtest
# start swarming
make unload
```

.gitignore

@@ -12,4 +12,7 @@
 terraform.tfstate*
 
 # dotenv
-.env
+.env
+
+# python cache (locust)
+__pycache__/

DEVELOPING.md

@@ -12,6 +12,7 @@ Recommended:
 - [K9s](https://k9scli.io/) - A Terminal UI for Kubernetes
 - [remake](https://remake.readthedocs.io/) - A better make
   - View them with `remake --tasks`
+- [locust](https://docs.locust.io/en/stable/what-is-locust.html) - A performance testing tool, required for load testing
 
 ## Local Development
 
@@ -114,6 +115,20 @@ Hit the endpoint:
 
 `make unapply-greetings` or `kubectl delete -f smoke-tests/greetings.yaml`
 
+## Load Testing
+
+After a locally built image and an API key is set:
+
+`make swarm`
+
+This will apply the agent, apply the echoserver, and start locust.
+
+Navigate to `http://0.0.0.0:8089/` in your browser and set users and spawn rate, e.g. 5000 and 100, and hit Start swarming.
+
+To tear down the load test, `ctrl+c` in the terminal running and `make unswarm`.
+
+See more details in [`smoke-tests/loadtest.md`](./smoke-tests/loadtest.md)
+
 ## Debugging
 
 From an agent pod terminal, which must be run in privileged mode:

Makefile

@@ -59,3 +59,15 @@ apply-greetings:
 .PHONY: unapply-greetings
 unapply-greetings:
 	kubectl delete -f smoke-tests/greetings.yaml
+
+# deploy echoserver in already-running cluster and start locust
+.PHONY: swarm
+swarm: apply-ebpf-agent
+	kubectl apply -f smoke-tests/echoserver.yaml
+	cd smoke-tests && locust
+
+# teardown load test setup
+.PHONY: unswarm
+unswarm:
+	kubectl delete -f smoke-tests/echoserver.yaml
+	make unapply-ebpf-agent

smoke-tests/echoserver.yaml

@@ -40,4 +40,4 @@ spec:
     - name: http
       port: 80
       targetPort: 80
-  type: LoadBalancers
+  type: LoadBalancer