--- title: "App Rollout via ConfigMap Data Change" description: "A Deployment that mounts a ConfigMap; updating the data in the ConfigMap triggers a rollout of the Deployment" url: "https://www.pulumi.com/dev/examples/kubernetes-ts-configmap-rollout/" image: "https://www.pulumi.com/assets/og/dev/examples/kubernetes-ts-configmap-rollout.png" --- # App Rollout via ConfigMap Data Change A Deployment that mounts a ConfigMap; updating the data in the ConfigMap triggers a rollout of the Deployment - Source on GitHub: https://github.com/pulumi/examples/tree/master/kubernetes-ts-configmap-rollout - Deploy with Pulumi: https://app.pulumi.com/new?template=https%3A%2F%2Fgithub.com%2Fpulumi%2Fexamples%2Ftree%2Fmaster%2Fkubernetes-ts-configmap-rollout ## Get started with this example This example lives in the [pulumi/examples](https://github.com/pulumi/examples/tree/master/kubernetes-ts-configmap-rollout) repo. Pull down just this directory to follow along: ```bash git clone --filter=blob:none --sparse https://github.com/pulumi/examples pulumi-examples git -C pulumi-examples sparse-checkout set kubernetes-ts-configmap-rollout cd pulumi-examples/kubernetes-ts-configmap-rollout ``` 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://www.pulumi.com/docs/get-started/install/) and [Configuring Pulumi Kubernetes](https://www.pulumi.com/docs/intro/cloud-providers/kubernetes/setup/) 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 isMinikube ``` 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 `` 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 ``` 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://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`. This is a meaningful difference from plain `kubectl`, which by default will *not* trigger a rollout of the containers that reference a `ConfigMap` when its data changes — instead the kubelet silently syncs the new data to the containers after its TTL expires. Pulumi plans an explicit, safe rollout: > 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 up` 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 "Google" Google ```