Adapt ingress section to wek8s

2026-08-18 11:36:36 +00:00 · 2019-05-25 20:31:06 -05:00
parent 25e2f8eca8
commit a8605a9316
3 changed files with 313 additions and 5 deletions
@@ -1,4 +1,4 @@
-# Healthchecks
+# Healthchecks (extra material)

 - Kubernetes provides two kinds of healthchecks: liveness and readiness

@@ -0,0 +1,308 @@
+# Exposing HTTP services with Ingress resources
+
+- *Services* give us a way to access a pod or a set of pods
+
+- Services can be exposed to the outside world:
+
+  - with type `NodePort` (on a port >30000)
+
+  - with type `LoadBalancer` (allocating an external load balancer)
+
+- What about HTTP services?
+
+  - how can we expose `webui`, `rng`, `hasher`?
+
+  - the Kubernetes dashboard?
+
+  - a new version of `webui`?
+
+---
+
+## Exposing HTTP services
+
+- If we use `NodePort` services, clients have to specify port numbers
+
+  (i.e. http://xxxxx:31234 instead of just http://xxxxx)
+
+- `LoadBalancer` services are nice, but:
+
+  - they are not available in all environments
+
+  - they often carry an additional cost (e.g. they provision an ELB)
+
+  - they require one extra step for DNS integration
+    <br/>
+    (waiting for the `LoadBalancer` to be provisioned; then adding it to DNS)
+
+---
+
+## Ingress resources
+
+- Kubernetes API resource (`kubectl get ingress`/`ingresses`/`ing`)
+
+- Designed to expose HTTP services
+
+- Basic features:
+
+  - load balancing
+  - SSL termination
+  - name-based virtual hosting
+
+- Can also route to different services depending on:
+
+  - URI path (e.g. `/api`→`api-service`, `/static`→`assets-service`)
+  - Client headers, including cookies (for A/B testing, canary deployment...)
+  - and more!
+
+---
+
+## Principle of operation
+
+- Step 1: deploy an *ingress controller*
+
+  - ingress controller = load balancer + control loop
+
+  - the control loop watches over ingress resources, and configures the LB accordingly
+
+- Step 2: setup DNS
+
+  - associate DNS entries with the load balancer address
+
+- Step 3: create *ingress resources*
+
+  - the ingress controller picks up these resources and configures the LB
+
+- Step 4: profit!
+
+---
+
+## Ingress in action
+
+- We will deploy the Traefik ingress controller
+
+  - this is an arbitrary choice
+
+  - maybe motivated by the fact that Traefik releases are named after cheeses
+
+- For DNS, we will use [nip.io](http://nip.io/)
+
+  - `*.1.2.3.4.nip.io` resolves to `1.2.3.4`
+
+- We will create ingress resources for various HTTP services
+
+---
+
+## Running Traefik on our cluster
+
+- We provide a YAML file (`k8s/traefik.yaml`) which is essentially the sum of:
+
+  - [Traefik's Daemon Set resources](https://github.com/containous/traefik/blob/v1.7/examples/k8s/traefik-ds.yaml) (patched with `hostNetwork` and tolerations)
+
+  - [Traefik's RBAC rules](https://github.com/containous/traefik/blob/v1.7/examples/k8s/traefik-rbac.yaml) allowing it to watch necessary API objects
+
+.exercise[
+
+- Apply the YAML:
+  ```bash
+  kubectl apply -f ~/container.training/k8s/traefik.yaml
+  ```
+
+]
+
+---
+
+## Checking that Traefik runs correctly
+
+- If Traefik started correctly, we now have a web server listening on each node
+
+.exercise[
+
+- Check that Traefik is serving 80/tcp:
+  ```bash
+  curl localhost
+  ```
+
+]
+
+We should get a `404 page not found` error.
+
+This is normal: we haven't provided any ingress rule yet.
+
+---
+
+## Setting up DNS
+
+- To make our lives easier, we will use [nip.io](http://nip.io)
+
+- Check out `http://webui.A.B.C.D.nip.io`
+
+  (replacing A.B.C.D with the IP address of `node1`)
+
+- We should get the same `404 page not found` error
+
+  (meaning that our DNS is "set up properly", so to speak!)
+
+---
+
+## Traefik web UI
+
+- Traefik provides a web dashboard
+
+- With the current install method, it's listening on port 8080
+
+.exercise[
+
+- Go to `http://node1:8080` (replacing `node1` with its IP address)
+
+<!-- ```open http://node1:8080``` -->
+
+]
+
+---
+
+## Ingress with the wek8s generic chart
+
+- The wek8s generic chart that we used earlier can generate an Ingress for us
+
+- All we have to do is add a few lines to the YAML file (`values-webui.yaml`)
+
+- ... And update the Helm release `webui` to use these new values
+
+.exercise[
+
+- Add the following snippet to the `values-webui.yaml` file:
+  ```yaml
+    ingress:
+      enabled: true
+      hosts:
+      - webui.`A.B.C.D`.nip.io
+  ```
+  (Where `A.B.C.D` is the IP address of node1, that we used earlier)
+
+]
+
+---
+
+## Update the Helm release
+
+- Now, we need to use these new values
+
+- We will use `helm upgrade` to run the templates and apply them to the cluster
+
+.exercise[
+
+- Update the Helm release:
+  ```bash
+  helm upgrade webui wek8s-generic-service --values=values-webui.yaml
+  ```
+
+]
+
+We should see an Ingress resource appear in the output.
+
+---
+
+## Access the service
+
+- Go back to the browser tab where we were loading webui.A.B.C.D.nip.io
+
+- Hit reload ...
+
+- ... And we should we the web UI for DockerCoins!
+
+---
+
+## What does an Ingress look like?
+
+- Let's inspect the Ingress generated by the generic service chart!
+
+.exercise[
+
+- Dump the YAML for the Ingress:
+  ```bash
+  kubectl get ingress webui-ingress -o yaml
+  ```
+
+]
+
+---
+
+## Creating an Ingress by hand
+
+If we need to, here is a minimal host-based ingress resource:
+
+```yaml
+apiVersion: extensions/v1beta1
+kind: Ingress
+metadata:
+  name: webui
+spec:
+  rules:
+  - host: webui.`A.B.C.D`.nip.io
+    http:
+      paths:
+      - path: /
+        backend:
+          serviceName: webui
+          servicePort: 80
+
+```
+
+---
+
+## Using multiple ingress controllers
+
+- You can have multiple ingress controllers active simultaneously
+
+  (e.g. Traefik and NGINX)
+
+- You can even have multiple instances of the same controller
+
+  (e.g. one for internal, another for external traffic)
+
+- The `kubernetes.io/ingress.class` annotation can be used to tell which one to use
+
+- It's OK if multiple ingress controllers configure the same resource
+
+  (it just means that the service will be accessible through multiple paths)
+
+---
+
+## Using Ingress on wek8s
+
+- Each wek8s cluster has a wildcard domain mapped to it
+
+- For instance, phoenix has `*.phoenix.dev.wwrk.co`
+
+- To be reachable from outside, we must use the ingress class `nginx-external`
+
+- This is done through an annotation, like this:
+
+```yaml
+ingress:
+  enabled: true
+  hosts:
+  - webui.phoenix.dev.wwrk.co
+  annotations:
+    kubernetes.io/ingress.class: nginx-external
+```
+
+---
+
+## Extra goodies
+
+- The wek8s generic service chart can also provide:
+
+  - TLS
+
+  - HTTP Basic Auth
+
+  - GRPC with HTTP/2
+
+- For more details, we can look at:
+
+  - the `values.yaml` file
+
+  - the chart's README
+
+  - the file `templates/ingress.yaml` in the chart
@@ -88,10 +88,11 @@ chapters:
  - k8s/kubectlexpose.md
  - k8s/shippingimages.md
  - k8s/buildshiprun-dockerhub.md
- - k8s/ourapponkube.md
-  - k8s/scalingdockercoins.md
+  - k8s/ourapponkube.md
+- - k8s/scalingdockercoins.md
  - shared/hastyconclusions.md
  - k8s/daemonset.md
+  - k8s/namespaces.md
  - k8s/rollout.md
  - k8s/setup-k8s.md
  - wek8s/connecting.md
@@ -101,8 +102,7 @@ chapters:
  - k8s/localkubeconfig.md
  - k8s/accessinternal.md
  - wek8s/helm.md
-  - k8s/namespaces.md
-  - k8s/ingress.md
+  - wek8s/ingress.md
  - k8s/prometheus.md
  - k8s/volumes.md
  - k8s/configuration.md