From 843e542937eee16ff5447b74b5654c40cfd89342 Mon Sep 17 00:00:00 2001
From: Jawad Seddar <jawad.seddar@algolia.com>
Date: Thu, 12 Nov 2020 16:37:35 +0100
Subject: [PATCH] Log collection example for sidecar containers (#64)

* Log collection example for sidecar containers

* Add service and update readme

* Update 16-sidecar-containers/README.md

Co-authored-by: Matthieu Dumont <5095856+Jerska@users.noreply.github.com>
---
 16-sidecar-containers/01-sidecar.yml | 56 +++++++++++++++++++++++-----
 16-sidecar-containers/README.md      | 12 ++++--
 2 files changed, 56 insertions(+), 12 deletions(-)

diff --git a/16-sidecar-containers/01-sidecar.yml b/16-sidecar-containers/01-sidecar.yml
index 11c0aff..97f8281 100644
--- a/16-sidecar-containers/01-sidecar.yml
+++ b/16-sidecar-containers/01-sidecar.yml
@@ -3,20 +3,58 @@ apiVersion: v1
 kind: Pod
 metadata:
   name: two-containers
+  labels:
+    app: sidecar-container
 spec:
   volumes:
-    - name: shared-data
+    - name: shared-logs
       emptyDir: {}
+    - name: fluentd-config
+      configMap:
+        name: fluentd
   containers:
     - name: nginx
       image: nginx
+      ports:
+        - containerPort: 80
       volumeMounts:
-        - name: shared-data
-          mountPath: /usr/share/nginx/html
-    - name: debian
-      image: debian
+        - name: shared-logs
+          mountPath: /var/log/nginx
+    - name: fluentd
+      image: fluent/fluentd:v1.11-1
       volumeMounts:
-        - name: shared-data
-          mountPath: /pod-data
-      command: ["/bin/sh"]
-      args: ["-c", "echo Hello from the debian container > /pod-data/index.html"]
+        - name: shared-logs
+          mountPath: /logs
+        - name: fluentd-config
+          mountPath: /fluentd/etc
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: fluentd
+data:
+  fluent.conf: |
+    <source>
+      @type tail
+      path /logs/*
+      pos_file /tmp/fluentd-nginx-pos.log
+      tag nginx
+      <parse>
+        @type nginx
+      </parse>
+    </source>
+
+    <match nginx>
+      @type stdout
+    </match>
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: nginx
+spec:
+  ports:
+    - port: 80
+      targetPort: 80
+  selector:
+    app: sidecar-container
diff --git a/16-sidecar-containers/README.md b/16-sidecar-containers/README.md
index df63880..691dcf0 100644
--- a/16-sidecar-containers/README.md
+++ b/16-sidecar-containers/README.md
@@ -14,7 +14,7 @@ spec:
   - name: container1
     image: nginx
   - name: container2
-    image: busybox
+    image: fluentd
 ```
 
 Here we have 2 containers: `container1` and `container2`.
@@ -33,14 +33,20 @@ Istio, the service mesh tool, installs a sidecar container to do its job: https:
 
 ## Exercices
 
-Review and apply the file [01-sidecar.yml](01-sidecar.yml). Connect to the `nginx` container and look at the file system in `/usr/share/nginx/html`.
+Review and apply the file [01-sidecar.yml](01-sidecar.yml).
+
+Connect to the `nginx` container (`kubectl exec -it two-containers -c nginx -- /bin/sh`) and look at the file system in `/var/log/nginx`.
+
+Do the same for the `fluentd` container and this time look in `/logs`. What do you see?
+
+Tail the logs from the fluentd pod (`kubectl logs -f two-containers -c fluentd`) and in another terminal window, send requests to the nginx service with a `curl` from a separate pod (or nginx's pod itself). What do you see? How do you explain it?
 
 This exercice is taken from the [official Kubernetes documentation](https://kubernetes.io/docs/tasks/access-application-cluster/communicate-containers-same-pod-shared-volume/#creating-a-pod-that-runs-two-containers).
 
 ## Clean up
 
 ```sh
-kubectl delete service,deployment,pod --all
+kubectl delete service,deployment,pod,configmap --all
 ```
 
 ## Links