Initial Commit

.dockerignore

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+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Coverage output
+coverage.out
+profile.cov
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof
+
+# vim files
+*.swp
+
+# Pycharm/IDEA
+.idea/

.gitignore

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+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Coverage
+coverage.out
+
+# Bild artifacts
+k8s-signal-logger
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof
+
+.idea/
+
+# Ignore vim files
+*.swp
+
+release.sh

Dockerfile

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+# To build:
+# $ docker run --rm -v $(pwd):/go/src/github.com/micahhausler/k8s-signal-logger -w /go/src/github.com/micahhausler/k8s-signal-logger golang:1.7  go build -v -a -tags netgo -installsuffix netgo -ldflags '-w'
+# $ docker build -t micahhausler/k8s-signal-logger .
+#
+# To run:
+# $ docker run micahhausler/k8s-signal-logger
+
+FROM alpine
+
+MAINTAINER Micah Hausler, <[email protected]>
+
+RUN apk -U add ca-certificates
+
+COPY k8s-signal-logger /bin/k8s-signal-logger
+RUN chmod 755 /bin/k8s-signal-logger
+
+EXPOSE 8080
+
+ENTRYPOINT ["/bin/k8s-signal-logger"]

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2016 Micah Hausler
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# k8s-signal-logger
+
+k8s-signal-logger is a simple program for observing how Kubernetes responds to
+[liveness and readiness probes](http://kubernetes.io/docs/api-reference/v1/definitions/#_v1_container)
+
+There are 3 endpoints to the container:
+
+- `/healthz` - Used for the health check
+- `/ready` - Used for the readiness check
+- `/` - A homepage handler - always responds with `200`
+
+## Try it out
+
+The following commands run:
+
+- Create the deployment and service
+- Get the service's nodePort and a node's IP
+- Run Apache bench against it
+- Update the deployment. Once the deployment is completed, you can see the results from apache bench
+
+```
+kubectl create -f deployment.yaml -f service.yaml
+export PORT=$(kubectl get -f service.yaml -o json | jq -r .spec.ports[0].nodePort)
+export NODE=$(kubectl get no -o json | jq -r .items[0].status.addresses[0].address)
+ab -n 1000000 -c 20 http://$NODE:$PORT/
+
+# In a separate terminal
+# - change a label on deployment.yaml
+kubectl replace -f deployment.yaml
+```
+
+## License
+MIT License. See [License](/LICENSE) for full text

deployment.yaml

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+apiVersion: extensions/v1beta1
+kind: Deployment
+metadata:
+  annotations:
+    description: k8s-signal-logger
+  labels:
+    app: k8s-signal-logger
+  name: k8s-signal-logger
+  namespace: default
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: k8s-signal-logger
+  strategy:
+    rollingUpdate:
+      maxSurge: "50%"
+      maxUnavailable: 0
+    type: RollingUpdate
+  template:
+    metadata:
+      annotations:
+        description: k8s-signal-logger
+      labels:
+        app: k8s-signal-logger
+        server: web
+      name: k8s-signal-logger
+    spec:
+      containers:
+      - name: k8s-signal-logger
+        image: micahhausler/k8s-signal-logger
+        livenessProbe:
+          failureThreshold: 3
+          httpGet:
+            path: /healthz
+            port: 8080
+            scheme: HTTP
+          initialDelaySeconds: 5
+          periodSeconds: 4
+          successThreshold: 1
+          timeoutSeconds: 1
+        readinessProbe:
+          failureThreshold: 1
+          httpGet:
+            path: /ready
+            port: 8080
+            scheme: HTTP
+          initialDelaySeconds: 5
+          periodSeconds: 10
+          successThreshold: 1
+        ports:
+        - containerPort: 8080
+          protocol: TCP
+      dnsPolicy: Default
+      restartPolicy: Always
+      terminationGracePeriodSeconds: 30

main.go

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+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+var ok bool
+
+var (
+	Term os.Signal = syscall.SIGTERM
+)
+
+// log the Signal to STDOUT
+func logSignal(c chan os.Signal) {
+	for s := range c {
+		log.Println("Got signal:", s)
+		ok = false
+	}
+
+}
+
+func main() {
+	ok = true
+	c := make(chan os.Signal)
+	signal.Notify(c, Term)
+
+	go logSignal(c)
+	log.Println("starting server at :8080")
+	http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
+		if ok {
+			log.Printf("/healthz - OK - %d", http.StatusOK)
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte("OK"))
+			return
+		} else {
+			log.Printf("/healthz - FAIL - %d", http.StatusServiceUnavailable)
+			w.WriteHeader(http.StatusServiceUnavailable)
+			w.Write([]byte("FAIL"))
+			return
+		}
+
+	})
+	http.HandleFunc("/ready", func(w http.ResponseWriter, r *http.Request) {
+		if ok {
+			log.Printf("/ready - OK - %d", http.StatusOK)
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte("OK"))
+			return
+		} else {
+			log.Printf("/ready - FAIL - %d", http.StatusServiceUnavailable)
+			w.WriteHeader(http.StatusServiceUnavailable)
+			w.Write([]byte("FAIL"))
+			return
+		}
+
+	})
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		log.Printf("/- OK - %d", http.StatusOK)
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte("Welcome!\n"))
+	})
+	http.ListenAndServe(":8080", nil)
+}

service.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  labels:
+    app: k8s-signal-logger
+  name: k8s-signal-logger
+  namespace: default
+spec:
+  ports:
+  - name: http
+    port: 8080
+    protocol: TCP
+    targetPort: 8080
+  selector:
+    app: k8s-signal-logger
+  type: NodePort