Merge pull request #28 from twexler/dynamic-label-selector

Use a configuration value for the label selector when discovering goldpinger pods

.travis.yml

@@ -1,7 +1,15 @@
 language: go
 
+services:
+  - docker
+
 go:
   - "1.10.x"
   - master
 
-script: go get -u github.com/golang/dep/cmd/dep && make vendor && make
+script:
+  - docker --version
+  - go get -u github.com/golang/dep/cmd/dep && make vendor && make && make build
+  - docker images
+  - make build-multistage
+  - docker images

Dockerfile

@@ -0,0 +1,27 @@
+FROM golang:1.11-alpine as builder
+
+# Install our build tools
+
+RUN apk add --update git make bash
+RUN go get -u github.com/golang/dep/cmd/dep
+
+# Get sources
+
+RUN go get github.com/bloomberg/goldpinger/cmd/goldpinger
+WORKDIR /go/src/github.com/bloomberg/goldpinger
+
+# Install our dependencies
+
+RUN make vendor
+
+# Build goldpinger
+
+RUN make bin/goldpinger
+
+# Build the asset container, copy over goldpinger
+
+FROM scratch
+COPY --from=builder /go/src/github.com/bloomberg/goldpinger/bin/goldpinger /goldpinger
+COPY ./static /static
+ENTRYPOINT ["/goldpinger", "--static-file-path", "/static"]
+

Makefile

@@ -1,5 +1,5 @@
 name ?= goldpinger
-version ?= 1.0.2
+version ?= 1.1.0
 bin ?= goldpinger
 pkg ?= "github.com/bloomberg/goldpinger"
 tag = $(name):$(version)
@@ -22,8 +22,11 @@ swagger:
 	swagger generate server -t pkg -f ./swagger.yml --exclude-main -A goldpinger && \
 	swagger generate client -t pkg -f ./swagger.yml -A goldpinger
 
+build-multistage:
+	sudo docker build -t $(tag) -f ./Dockerfile .
+
 build: bin/$(bin)
-	sudo docker build -t $(tag) -f ./build/Dockerfile .
+	sudo docker build -t $(tag) -f ./build/Dockerfile-simple .
 
 tag:
 	sudo docker tag $(tag) $(namespace)$(tag)

README.md

@@ -3,7 +3,7 @@
 __Goldpinger__ makes calls between its instances for visibility and alerting.
 It runs as a `DaemonSet` on `Kubernetes` and produces `Prometheus` metrics that can be scraped, visualised and alerted on.
 
-Oh, and it gives you the graph below for your cluster.
+Oh, and it gives you the graph below for your cluster. Check out the [video explainer](https://youtu.be/DSFxRz_0TU4).
 
 ![](./extras/screenshot.png)
 
@@ -13,6 +13,8 @@ Oh, and it gives you the graph below for your cluster.
 - [Rationale](#rationale)
 - [Quick start](#quick-start)
 - [Building](#building)
+  - [Compiling using a multi-stage Dockerfile](#compiling-using-a-multi-stage-dockerfile)
+  - [Compiling locally](#compiling-locally)
 - [Installation](#installation)
   - [Authentication with Kubernetes API](#authentication-with-kubernetes-api)
   - [Example YAML](#example-yaml)
@@ -31,6 +33,8 @@ We built __Goldpinger__ to troubleshoot, visualise and alert on our networking l
 
 It's small, simple and you'll wonder why you hadn't had it before.
 
+If you'd like to know more, you can watch [our presentation at Kubecon 2018 Seattle](https://youtu.be/DSFxRz_0TU4).
+
 
 ## Quick start
 
@@ -44,9 +48,28 @@ Note, that in order to guarantee correct versions of dependencies, the project [
 
 ## Building
 
+The repo comes with two ways of building a `docker` image: compiling locally, and compiling using a multi-stage `Dockerfile` image.
+
+### Compiling using a multi-stage Dockerfile
+
+You will need `docker` version 17.05+ installed to support multi-stage builds.
+
+```sh
+# step 1: launch the build
+make build-multistage
+
+# step 2: push the image somewhere
+namespace="docker.io/myhandle/" make tag
+namespace="docker.io/myhandle/" make push
+```
+
+This was contributed via [@michiel](https://github.com/michiel) - kudos !
+
+### Compiling locally
+
 In order to build `Goldpinger`, you are going to need `go` version 1.10+, `dep`, and `docker`.
 
-Building from source code consists of compiling the binary and building a [Docker image](./build/Dockerfile):
+Building from source code consists of compiling the binary and building a [Docker image](./build/Dockerfile-simple):
 
 ```sh
 # step 0: check out the code into your $GOPATH
@@ -80,7 +103,9 @@ namespace="docker.io/myhandle/" make push
 ### Example YAML
 
 
-Here's an example of what you can do (using the in-cluster authentication to `Kubernetes` apiserver):
+Here's an example of what you can do (using the in-cluster authentication to `Kubernetes` apiserver). 
+
+:warning: Replace `docker.io/mynamespace-replaceme/goldpinger:1.0.0` with the actual tag you built.
 
 ```yaml
 ---
@@ -134,6 +159,24 @@ spec:
     app: goldpinger
 ```
 
+Note, that you will also need to add an RBAC rule to allow `Goldpinger` to list other pods. If you're just playing around, you can consider a view-all default rule:
+
+```yaml
+---
+apiVersion: rbac.authorization.k8s.io/v1beta1
+kind: ClusterRoleBinding
+metadata:
+  name: default
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: view
+subjects:
+  - kind: ServiceAccount
+    name: default
+    namespace: default
+```
+
 You can also see [an example of using `kubeconfig` in the `./extras`](./extras/example-with-kubeconfig.yaml).
 
 ## Usage

extras/example-serviceaccounts.yml

@@ -0,0 +1,49 @@
+---
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: goldpinger
+spec:
+  updateStrategy:
+    type: RollingUpdate
+  selector:
+    matchLabels:
+      app: goldpinger
+      version: "1.0.0"
+  template:
+    metadata:
+      labels:
+        app: goldpinger
+        version: "1.0.0"
+    spec:
+      containers:
+        - name: goldpinger
+          env:
+            - name: HOST
+              value: "0.0.0.0"
+            - name: PORT
+              value: "80"
+            # injecting real hostname will make for easier to understand graphs/metrics
+            - name: HOSTNAME
+              valueFrom:
+                fieldRef:
+                  fieldPath: spec.nodeName
+          image: "docker.io/mynamespace-replaceme/goldpinger:1.0.0"
+          ports:
+            - containerPort: 80
+              name: http
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: goldpinger
+  labels:
+    app: goldpinger
+spec:
+  type: NodePort
+  ports:
+    - port: 80
+      nodePort: 30080
+      name: http
+  selector:
+    app: goldpinger

pkg/goldpinger/config.go

@@ -26,5 +26,6 @@ var GoldpingerConfig = struct {
 	Hostname         string `long:"hostname" description:"Hostname to use" env:"HOSTNAME"`
 	Port             int    `long:"client-port-override" description:"(for testing) use this port when calling other instances" env:"CLIENT_PORT_OVERRIDE"`
 	UseHostIP        bool   `long:"use-host-ip" description:"When making the calls, use host ip (defaults to pod ip)" env:"USE_HOST_IP"`
+	LabelSelector    string `long:"label-selector" description:"label selector to use to discover goldpinger pods in the cluster" env:"LABEL_SELECTOR" default:"app=goldpinger"`
 	KubernetesClient *kubernetes.Clientset
 }{}

pkg/goldpinger/k8s.go

@@ -16,14 +16,24 @@ package goldpinger
 
 import (
 	"log"
-
+	"io/ioutil"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
-func GetAllPods() map[string]string {
+func getNamespace() string {
+	b, err := ioutil.ReadFile("/var/run/secrets/kubernetes.io/serviceaccount/namespace")
+	if err != nil {
+		log.Println("Unable to determine namespace: ", err.Error())
+		return ""
+	}
+	namespace := string(b)
+	return namespace
+}
 
+// GetAllPods returns a map of Pod IP to Host IP based on a label selector defined in config
+func GetAllPods() map[string]string {
 	timer := GetLabeledKubernetesCallsTimer()
-	pods, err := GoldpingerConfig.KubernetesClient.CoreV1().Pods("").List(metav1.ListOptions{LabelSelector: "app=goldpinger"})
+	pods, err := GoldpingerConfig.KubernetesClient.CoreV1().Pods(getNamespace()).List(metav1.ListOptions{LabelSelector: GoldpingerConfig.LabelSelector})
 	if err != nil {
 		log.Println("Error getting pods for selector: ", err.Error())
 		CountError("kubernetes_api")

static/index.html

@@ -90,8 +90,8 @@ limitations under the License.
           <ul class="nav navbar-nav">
             <li class="active"><a href="#">Graph</a></li>
             <li><a href="#" id="show-data">Data</a></li>
-            <li><a href="/check_all" >Raw</a></li>
-            <li><a href="/metrics" >Metrics</a></li>
+            <li><a href="check_all" >Raw</a></li>
+            <li><a href="metrics" >Metrics</a></li>
           </ul>
         <div class="navbar-form navbar-left" role="search">
           <div class="form-group">