Add example showing rollout triggered on ConfigMap data

kubernetes-ts-configmap-rollout/Pulumi.yaml

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+name: configmap-rollout
+description: A Deployment that mounts a ConfigMap; updating the data in the ConfigMap triggers a rollout of the Deployment
+runtime: nodejs

kubernetes-ts-configmap-rollout/README.md

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+# Kubernetes: Triggering a rollout of an app by changing ConfigMap data
+
+Uses nginx to reverse-proxy traffic to `pulumi.github.io`. The nginx configuration is contained in
+the file `default.conf` in this directory; this program reads that file and puts it in a
+`ConfigMap`. Hence, changing data in that file will cause register as a change in the `ConfigMap`'s
+data, which will trigger a rollout of the nginx `Deployment`.
+
+![configmapRollout](images/rollout.gif "ConfigMap-induced Rollout")
+
+## Running the App
+
+Follow the steps in [Pulumi Installation and Setup](https://docs.pulumi.com/install/) and
+[Configuring Pulumi Kubernetes](https://docs.pulumi.com/reference/kubernetes.html#configuration) to
+get setup with Pulumi and Kubernetes.
+
+Install dependencies:
+
+```sh
+npm install
+```
+
+Create a new stack:
+
+```sh
+$ pulumi stack init
+Enter a stack name: configmap-rollout-dev
+```
+
+This example will attempt to expose the `nginx` deployment to the Internet with
+a `Service` of type `LoadBalancer`. Since minikube does not support
+`LoadBalancer`, the application already knows to use type `ClusterIP` instead;
+all you need to do is to tell it whether you're deploying to minikube:
+
+```sh
+pulumi config set rolloutTest:isMinikube <value>
+```
+
+Perform the deployment:
+
+```sh
+$ pulumi up
+Updating stack 'configmap-rollout-dev'
+Performing changes:
+
+ Type Name Status Info
+ + pulumi:pulumi:Stack configmap-rollout-configmap-rollout-dev created
+ + ├─ kubernetes:core:ConfigMap nginx created
+ + ├─ kubernetes:apps:Deployment nginx created
+ + └─ kubernetes:core:Service nginx created
+
+---outputs:---
+frontendIp: "35.193.210.254"
+
+info: 4 changes performed:
+ + 4 resources created
+Update duration: 49.612528861s
+
+Permalink: https://app.pulumi.com/hausdorff/configmap-rollout-dev/updates/1
+```
+
+We can see here in the `---outputs:---` section that our proxy was allocated a public IP, in this
+case `35.193.210.254`. It is exported with a stack output variable, `frontendIp`. We can use `curl`
+and `grep` to retrieve the `<title>` of the site the proxy points at.
+
+```sh
+$ curl -sL $(pulumi stack output frontendIp):80 | grep -C 1 "<title>"
+
+ <title>Pulumi. Serverless // Containers // Infrastructure // Cloud // DevOps</title>
+
+```
+
+Now, open `default.conf` and change `.node.server` and `.server.location.proxy_set_header` to point
+at `google.com`. If you're on macOS you can run `sed -i bak "s/pulumi.github.io/google.com/g"
+default.conf`
+
+The result should look like this:
+
+```conf
+upstream node {
+ server google.com;
+}
+server {
+ listen 80;
+ server_name _;
+ root /usr/share/nginx/html;
+ location / {
+ proxy_set_header X-Real-IP \$remote_addr;
+ proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
+ proxy_set_header Host google.com;
+ proxy_pass http:https://node;
+ proxy_redirect off;
+ port_in_redirect off;
+ }
+}
+```
+
+Running `preview` now shows that this change will cause us to replace the `ConfigMap` with a new one
+containing the new data, and subsequently trigger a rollout in the `Deployment`.
+
+> NOTE: This rollout is safe! Pulumi executes this plan with the following steps:
+>
+> 1. Create a new `ConfigMap` with a new name and the new data.
+> 1. Update the `PodTemplate` of the `Deployment` to point at the new `ConfigMap`. This update
+>  triggers the `Deployment` controller to try to roll out a new set of containers with mounts
+>  that contain this new data.
+> 1. Only once that succeeds, delete the old `ConfigMap`.
+
+```sh
+Previewing update of stack 'configmap-rollout-dev'
+ Type Name Status Info
+ * pulumi:pulumi:Stack configmap-rollout-configmap-rollout-dev no change
+ +- ├─ kubernetes:core:ConfigMap nginx replace changes: ~ data,metadata
+ ~ └─ kubernetes:apps:Deployment nginx update changes: ~ spec
+
+info: 2 changes previewed:
+ ~ 1 resource to update
+ +-1 resource to replace
+ 2 resources unchanged
+```
+
+Running `pulumi update` should similarly look something like this:
+
+```sh
+Updating stack 'configmap-rollout-dev'
+ Type Name Status Info
+ * pulumi:pulumi:Stack configmap-rollout-configmap-rollout-dev done
+ +- ├─ kubernetes:core:ConfigMap nginx replaced changes: ~ data,metadata
+ ~ └─ kubernetes:apps:Deployment nginx updated changes: ~ spec
+
+---outputs:---
+frontendIp: "35.193.210.254"
+
+info: 2 changes performed:
+ ~ 1 resource updated
+ +-1 resource replaced
+ 2 resources unchanged
+Update duration: 5.679919856s
+
+Permalink: https://app.pulumi.com/hausdorff/configmap-rollout-dev/updates/13
+```
+
+Now, if we `curl` the IP address once more, we see that it points at google.com!
+
+> *Note*: minikube does not support type `LoadBalancer`; if you are deploying to minikube, make sure
+> to run `kubectl port-forward svc/frontend 8080:80` to forward the cluster port to the local
+> machine and access the service via `localhost:8080`.
+
+```sh
+$ curl -sL $(pulumi stack output frontendIp) | grep -o "<title>Google</title>"
+<title>Google</title>
+```

kubernetes-ts-configmap-rollout/default.conf

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+upstream node {
+ server pulumi.github.io;
+}
+server {
+ listen 80;
+ server_name _;
+ root /usr/share/nginx/html;
+ location / {
+ proxy_set_header X-Real-IP \$remote_addr;
+ proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
+ proxy_set_header Host pulumi.github.io;
+ proxy_pass http:https://node;
+ proxy_redirect off;
+ port_in_redirect off;
+ }
+}