From 2a225de2f992e59a5653abe801f6cf4baf6df858 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 24 Jul 2021 21:23:40 -0400
Subject: [PATCH 1/6] Create an echo service docker image.

---
 kubernetes/autoscale/service/Dockerfile       | 17 +++++++++++
 kubernetes/autoscale/service/Makefile         | 21 ++++++++++++++
 kubernetes/autoscale/service/gunicorn.conf.py | 10 +++++++
 kubernetes/autoscale/service/main.py          | 28 +++++++++++++++++++
 kubernetes/autoscale/service/requirements.txt |  2 ++
 5 files changed, 78 insertions(+)
 create mode 100644 kubernetes/autoscale/service/Dockerfile
 create mode 100644 kubernetes/autoscale/service/Makefile
 create mode 100644 kubernetes/autoscale/service/gunicorn.conf.py
 create mode 100644 kubernetes/autoscale/service/main.py
 create mode 100644 kubernetes/autoscale/service/requirements.txt

diff --git a/kubernetes/autoscale/service/Dockerfile b/kubernetes/autoscale/service/Dockerfile
new file mode 100644
index 0000000..b9cf35f
--- /dev/null
+++ b/kubernetes/autoscale/service/Dockerfile
@@ -0,0 +1,17 @@
+FROM python:3.9
+
+RUN useradd -m -g nogroup server
+USER server
+
+WORKDIR /home/server
+ENV FLASK_APP=main.py
+
+# Perform the install of requirements first to avoid re-installing on every code change
+COPY requirements.txt /home/server/
+RUN pip install -r /home/server/requirements.txt
+
+COPY *.py /home/server/
+
+# CMD ["python", "/home/server/main.py"]
+
+CMD ["/home/server/.local/bin/gunicorn", "--config", "/home/server/gunicorn.conf.py", "main:app"]
diff --git a/kubernetes/autoscale/service/Makefile b/kubernetes/autoscale/service/Makefile
new file mode 100644
index 0000000..3de8eb0
--- /dev/null
+++ b/kubernetes/autoscale/service/Makefile
@@ -0,0 +1,21 @@
+IMAGE_NAME:=echoservice
+
+.PHONY: all
+all: build push
+
+.PHONY: build
+build:
+	docker build -t $(IMAGE_NAME) .
+
+.PHONY: push
+push:
+	docker tag $(IMAGE_NAME) gcr.io/hip-wharf-319304/$(IMAGE_NAME)
+	docker push gcr.io/hip-wharf-319304/$(IMAGE_NAME)
+
+.PHONY: clean
+clean:
+	docker rmi $(IMAGE_NAME) gcr.io/hip-wharf-319304/$(IMAGE_NAME) $(IMAGE_NAME)
+
+.PHONY: run
+run:
+	docker run --rm -i -t -p "8080:8080" $(IMAGE_NAME)
diff --git a/kubernetes/autoscale/service/gunicorn.conf.py b/kubernetes/autoscale/service/gunicorn.conf.py
new file mode 100644
index 0000000..0a4a199
--- /dev/null
+++ b/kubernetes/autoscale/service/gunicorn.conf.py
@@ -0,0 +1,10 @@
+import multiprocessing
+import os
+
+env_port = int(os.environ.get("PORT", 8080))
+
+bind = f"0.0.0.0:{env_port}"
+workers = max(2, multiprocessing.cpu_count() * 2 + 1)
+preload_app = True
+max_requests = 100
+max_requests_jitter = 50
diff --git a/kubernetes/autoscale/service/main.py b/kubernetes/autoscale/service/main.py
new file mode 100644
index 0000000..0669613
--- /dev/null
+++ b/kubernetes/autoscale/service/main.py
@@ -0,0 +1,28 @@
+import json
+import os
+
+from flask import Flask, request
+
+app = Flask(__name__)
+
+
+def get_request_params():
+    request_json = request.get_json(silent=True)
+    request_args = request.args
+    if request_json:
+        return request_json
+    elif request_args:
+        return request_args
+    else:
+        return None
+
+
+@app.route("/", methods=("GET", "POST"))
+def index():
+    return json.dumps(
+        {"headers": {k: v for k, v in request.headers}, "params": get_request_params()}
+    )
+
+
+if __name__ == "__main__":
+    app.run(host="0.0.0.0", port=int(os.environ.get("PORT", 8080)), debug=True)
diff --git a/kubernetes/autoscale/service/requirements.txt b/kubernetes/autoscale/service/requirements.txt
new file mode 100644
index 0000000..b94ded4
--- /dev/null
+++ b/kubernetes/autoscale/service/requirements.txt
@@ -0,0 +1,2 @@
+flask==1.1.2
+gunicorn==20.1.0

From 6f2ee8f88006bcb399ad5572edb7294a243bf899 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 24 Jul 2021 21:31:51 -0400
Subject: [PATCH 2/6] Make GCP project a variable also.

---
 kubernetes/autoscale/service/Makefile | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kubernetes/autoscale/service/Makefile b/kubernetes/autoscale/service/Makefile
index 3de8eb0..8688d0d 100644
--- a/kubernetes/autoscale/service/Makefile
+++ b/kubernetes/autoscale/service/Makefile
@@ -1,4 +1,5 @@
 IMAGE_NAME:=echoservice
+GCP_PROJECT:=hip-wharf-319304
 
 .PHONY: all
 all: build push
@@ -9,12 +10,12 @@ build:
 
 .PHONY: push
 push:
-	docker tag $(IMAGE_NAME) gcr.io/hip-wharf-319304/$(IMAGE_NAME)
-	docker push gcr.io/hip-wharf-319304/$(IMAGE_NAME)
+	docker tag $(IMAGE_NAME) gcr.io/$(GCP_PROJECT)/$(IMAGE_NAME)
+	docker push gcr.io/$(GCP_PROJECT)/$(IMAGE_NAME)
 
 .PHONY: clean
 clean:
-	docker rmi $(IMAGE_NAME) gcr.io/hip-wharf-319304/$(IMAGE_NAME) $(IMAGE_NAME)
+	docker rmi $(IMAGE_NAME) gcr.io/$(GCP_PROJECT)/$(IMAGE_NAME) $(IMAGE_NAME)
 
 .PHONY: run
 run:

From 35f326565994853f28c6a3ec5874626546e53fc9 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 24 Jul 2021 21:48:24 -0400
Subject: [PATCH 3/6] Add auto scale deployment.

---
 kubernetes/autoscale/k8s/autoscale.yaml | 35 +++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 kubernetes/autoscale/k8s/autoscale.yaml

diff --git a/kubernetes/autoscale/k8s/autoscale.yaml b/kubernetes/autoscale/k8s/autoscale.yaml
new file mode 100644
index 0000000..cda317f
--- /dev/null
+++ b/kubernetes/autoscale/k8s/autoscale.yaml
@@ -0,0 +1,35 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: autoscale-test
+  namespace: default
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: autoscale-test
+  template:
+    metadata:
+      labels:
+        app: autoscale-test
+    spec:
+      containers:
+        - name: echoservice
+          image: gcr.io/hip-wharf-319304/echoservice:latest
+          imagePullPolicy: IfNotPresent
+          ports:
+            - name: http
+              containerPort: 8080
+              protocol: TCP
+          livenessProbe:
+            httpGet:
+              path: /
+              port: http
+          readinessProbe:
+            httpGet:
+              path: /
+              port: http
+          resources:
+            requests:
+              cpu: "250m"
+              memory: "256Mi"

From 922247644469305ad134bde4888e0c989584960b Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 24 Jul 2021 22:20:42 -0400
Subject: [PATCH 4/6] Expose it as a service.

---
 kubernetes/autoscale/k8s/autoscale.yaml       | 14 +++++++++++++-
 kubernetes/autoscale/service/gunicorn.conf.py |  3 +--
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/kubernetes/autoscale/k8s/autoscale.yaml b/kubernetes/autoscale/k8s/autoscale.yaml
index cda317f..6d19918 100644
--- a/kubernetes/autoscale/k8s/autoscale.yaml
+++ b/kubernetes/autoscale/k8s/autoscale.yaml
@@ -4,7 +4,6 @@ metadata:
   name: autoscale-test
   namespace: default
 spec:
-  replicas: 3
   selector:
     matchLabels:
       app: autoscale-test
@@ -33,3 +32,16 @@ spec:
             requests:
               cpu: "250m"
               memory: "256Mi"
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: autoscale-test
+  namespace: default
+spec:
+  selector:
+    app: autoscale-test
+  type: LoadBalancer
+  ports:
+    - port: 80
+      targetPort: "http"
diff --git a/kubernetes/autoscale/service/gunicorn.conf.py b/kubernetes/autoscale/service/gunicorn.conf.py
index 0a4a199..984946b 100644
--- a/kubernetes/autoscale/service/gunicorn.conf.py
+++ b/kubernetes/autoscale/service/gunicorn.conf.py
@@ -1,10 +1,9 @@
-import multiprocessing
 import os
 
 env_port = int(os.environ.get("PORT", 8080))
 
 bind = f"0.0.0.0:{env_port}"
-workers = max(2, multiprocessing.cpu_count() * 2 + 1)
+workers = int(os.environ.get("WORKERS", 8))
 preload_app = True
 max_requests = 100
 max_requests_jitter = 50

From fc7e54ea8a217af0018646eb0cbc512fd7a22f3f Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 24 Jul 2021 22:25:40 -0400
Subject: [PATCH 5/6] Always pull image.

---
 kubernetes/autoscale/k8s/autoscale.yaml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kubernetes/autoscale/k8s/autoscale.yaml b/kubernetes/autoscale/k8s/autoscale.yaml
index 6d19918..6f37a7b 100644
--- a/kubernetes/autoscale/k8s/autoscale.yaml
+++ b/kubernetes/autoscale/k8s/autoscale.yaml
@@ -15,7 +15,10 @@ spec:
       containers:
         - name: echoservice
           image: gcr.io/hip-wharf-319304/echoservice:latest
-          imagePullPolicy: IfNotPresent
+          imagePullPolicy: Always
+          env:
+            - name: "WORKERS"
+              value: "8"
           ports:
             - name: http
               containerPort: 8080

From c1d18e0fe57c9ed04ad84e7303da3ebcf5aedcd3 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 24 Jul 2021 22:36:48 -0400
Subject: [PATCH 6/6] Scaling based on CPU usage.

---
 kubernetes/autoscale/k8s/autoscale.yaml | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/kubernetes/autoscale/k8s/autoscale.yaml b/kubernetes/autoscale/k8s/autoscale.yaml
index 6f37a7b..8e0a1f9 100644
--- a/kubernetes/autoscale/k8s/autoscale.yaml
+++ b/kubernetes/autoscale/k8s/autoscale.yaml
@@ -48,3 +48,17 @@ spec:
   ports:
     - port: 80
       targetPort: "http"
+---
+apiVersion: autoscaling/v1
+kind: HorizontalPodAutoscaler
+metadata:
+  name: autoscale-test
+  namespace: default
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: autoscale-test
+  minReplicas: 1
+  maxReplicas: 10
+  targetCPUUtilizationPercentage: 50