Closes jaegertracing#74 - Changed Kubernetes Template to use DaemonSet

Signed-off-by: Juraci Paixão Kröhling <[email protected]>

README.md

@@ -52,30 +52,48 @@ If changes are required for the configuration, the `edit` command can be used:
 
 ### Jaeger components
 
-The main production template deploys the Collector and the Query Service (with UI) as separate individually scalable services.
+The main production template deploys the Collector and the Query Service (with UI) as separate individually scalable services,
+as well as the Agent as `DaemonSet`.
 
     kubectl create -f https://raw.githubusercontent.com/jaegertracing/jaeger-kubernetes/master/jaeger-production-template.yml
 
 If the backing storage is not ready by the time the Collector/Agent start, they will fail and Kubernetes will reschedule the
 pod. It's advisable to either wait for the backing storage to stabilize, or to ignore such failures for the first few minutes.
 
 Once everything is ready, `kubectl get service jaeger-query` tells you where to find Jaeger URL, or 
-`minikube service jaeger-query --url` when using `minikube`
+`minikube service jaeger-query --url` when using `minikube`.
+
+As the agent is deployed as a `DaemonSet`, the node's IP address can be stored as an environment variable and passed down
+to the application as:
+
+```yaml
+env:
+- name: JAEGER_AGENT_HOST
+  valueFrom:
+    fieldRef:
+      fieldPath: status.hostIP
+```
 
 ### Deploying the agent as sidecar
 The Jaeger Agent is designed to be deployed local to your service, so that it can receive traces via UDP keeping your
-application's load minimal. As such, it's ideal to have the Agent to be deployed as a sidecar to your application's component,
-just add it as a container within any struct that supports `spec.containers`, like a `Pod`, `Deployment` and so on.
+application's load minimal. By default, the template above installs the agent as a `DaemonSet`, but this means that all
+pods running on a given node will send data to the same agent. If that's not suitable for your workload, an alternative
+is to deploy the agent as a sidecar. To accomplish that, just add it as a container within any struct that supports 
+`spec.containers`, like a `Pod`, `Deployment` and so on. More about this be found on the blog post 
+[Deployment strategies for the Jaeger Agent](https://medium.com/jaegertracing/deployment-strategies-for-the-jaeger-agent-1d6f91796d09).
 
-For instance, assuming that your application is named `myapp` and the image is for it is `mynamespace/hello-myimage`, your
+Assuming that your application is named `myapp` and the image is for it is `mynamespace/hello-myimage`, your
 `Deployment` descriptor would be something like:
 
 ```yaml
-- apiVersion: extensions/v1beta1
+- apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: myapp
   spec:
+    selector:
+      matchLabels:
+        app: myapp
     template:
       metadata:
         labels:

jaeger-production-template.yml

@@ -163,3 +163,42 @@ items:
     selector:
       jaeger-infra: query-pod
     type: LoadBalancer
+- apiVersion: extensions/v1beta1
+  kind: DaemonSet
+  metadata:
+    name: jaeger-agent
+    labels:
+      app: jaeger
+      jaeger-infra: agent-daemonset
+  spec:
+    template:
+      metadata:
+        labels:
+          app: jaeger
+          jaeger-infra: agent-instance
+      spec:
+        containers:
+        - name: agent-instance
+          image: jaegertracing/jaeger-agent:1.2
+          command:
+          - "/go/bin/agent-linux"
+          - "--config-file=/conf/agent.yaml"
+          volumeMounts:
+          - name: jaeger-configuration-volume
+            mountPath: /conf
+          ports:
+          - containerPort: 5775
+            protocol: UDP
+          - containerPort: 6831
+            protocol: UDP
+          - containerPort: 6832
+            protocol: UDP
+        hostNetwork: true
+        dnsPolicy: ClusterFirstWithHostNet
+        volumes:
+          - configMap:
+              name: jaeger-configuration
+              items:
+                - key: agent
+                  path: agent.yaml
+            name: jaeger-configuration-volume

production-elasticsearch/configmap.yml

@@ -36,3 +36,6 @@ data:
       password: changeme
     query:
       static-files: /go/jaeger-ui/
+  agent: |
+    collector:
+      host-port: "jaeger-collector:14267"

production/configmap.yml

@@ -34,3 +34,6 @@ data:
       keyspace: jaeger_v1_dc1
     query:
       static-files: /go/jaeger-ui/
+  agent: |
+    collector:
+      host-port: "jaeger-collector:14267"