doc: kubernetes example

This patch adds an example on how to run the plugin on a kubernetes cluster.

Author: Alessandro Puccetti

README.md

@@ -11,13 +11,49 @@ You need `/sys/kernel/debug/` in order to be able to build the eBPF program gene
 
 ## How to Run Scope HTTP Statistics Plugin
 
+This plugin requires:
+
+* kernel version [>=4.1](https://github.com/iovisor/bcc/blob/master/docs/kernel-versions.md) running on the host to be able to attach eBPF to kprobes.
+* Kernel build directory to be available in `/lib/modules/<kernel-version>/build`. Depending on your distribution you might need to add this symlink: `ln -s /lib/modules/<kernel-version>/build /lib/modules/<kernel-version>/source`.
+
+The Scope HTTP Statistics plugin works with `Weave Scope`, you need to have Scope up and running before you can use it. If the running plugin has been registered by Scope, you will see it in the list of `PLUGINS` in the bottom right of the UI (see the rectangle in the above figure).
+
+### Using a pre-built Docker image
+
+If you want to make sure of running the latest available version of the plugin, you can pull the image from docker hub.
+
+```
+docker pull weaveworksplugins/scope-http-statistics:latest
+```
+
+To run the Scope HTTP Statistics plugin you just need to run the following command.
+
+```
+sudo docker run --rm -it \
+ --privileged --net=host --pid=host \
+ -v /lib/modules:/lib/modules \
+ -v /usr/src:/usr/src \
+ -v /sys/kernel/debug/:/sys/kernel/debug/ \
+ -v /var/run/scope/plugins:/var/run/scope/plugins \
+ --name weaveworksplugins-scope-http-statistics weaveworksplugins/scope-http-statistics
+```
+
+### Kubernetes
+
+If you want to use the Scope HTTP Statistics plugin in an already set up Kubernetes cluster with Weave Scope running on it, you just need to run:
+
+```
+kubectl create -f https://github.com/weaveworks-plugins/scope-http-statistics/tree/master/deployments/k8s-http-statistics.yaml
+```
+
+### Recompiling
 * Run the HTTP Statistics plugin
 * `git clone git@github.com:weaveworks-plugins/scope-http-statistics.git`
-* `cd scope-http-statistics.sh; make`
+* `cd scope-http-statistics; make`
 
-**Note** If Scope HTTP Statistics plugin has been registered by Scope, you will see it in the list of `PLUGINS` in the bottom right of the UI (see the rectangle in the above figure).
+## Testing
 
-* In another terminal, run an `nginx` instance `docker run --rm --name http-statistics-nginx -p 8080:80 nginx`
+* Run an `nginx` instance `docker run --rm --name http-statistics-nginx -p 8080:80 nginx`
 * Run `sh test-http-statistics.sh`, press Ctrl+c to terminate the test.
 * Go to the Weave Scope UI [http://localhost:4040](http://localhost:4040).
 * Open the `http-statistics-nginx` container.

deployments/k8s-http-statistics.yaml

@@ -0,0 +1,48 @@
+apiVersion: extensions/v1beta1
+kind: DaemonSet
+metadata:
+ labels:
+ app: weavescope
+ weavescope-component: weavescope-http-statistics-plugin
+ name: weavescope-http-statistics-plugin
+spec:
+ template:
+ metadata:
+ labels:
+ app: weavescope
+ weavescope-component: weavescope-http-statistics-plugin
+ spec:
+ hostPID: true
+ hostNetwork: true
+ containers:
+ - name: weavescope-http-statistics-plugin
+ image: weaveworksplugins/scope-http-statistics:latest
+ securityContext:
+ privileged: true
+ volumeMounts:
+ - name: docker-sock
+ mountPath: /var/run/docker.sock
+ - name: scope-plugins
+ mountPath: /var/run/scope/plugins
+ - name: lib-modules
+ mountPath: /lib/modules
+ - name: usr-src
+ mountPath: /usr/src
+ - name: sys-kernel-debug
+ mountPath: /sys/kernel/debug
+ volumes:
+ - name: docker-sock
+ hostPath:
+ path: /var/run/docker.sock
+ - name: scope-plugins
+ hostPath:
+ path: /var/run/scope/plugins
+ - name: lib-modules
+ hostPath:
+ path: /lib/modules
+ - name: usr-src
+ hostPath:
+ path: /usr/src
+ - name: sys-kernel-debug
+ hostPath:
+ path: /sys/kernel/debug