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Deploying an application

We have successfully bootstrapped Flux on our cluster so now we can deploy an application. To demonstrate the difference between a GitOps-based delivery of an application and other methods, we'll migrate the UI component of the sample application which is currently using the kubectl apply -k approach to the new Flux deployment approach.

First let's remove the existing UI component so we can replace it:

~$kubectl delete namespace ui


Next, clone the repository we used to bootstrap Flux in the previous section:


~$git clone ssh://${GITOPS_IAM_SSH_KEY_ID}@git-codecommit.${AWS_REGION}.amazonaws.com/v1/repos/${EKS_CLUSTER_NAME}-gitops ~/environment/flux


Now, let's start populating the Flux repository by creating a directory for our "apps". This directory is designed to contain a sub-directory for each application component:


~$mkdir ~/environment/flux/apps


Then create a kustomization that lets Flux know about that directory:


~/environment/eks-workshop/modules/automation/gitops/flux/basic/apps.yaml
apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
kind: Kustomization
metadata:
  name: apps
  namespace: flux-system
spec:
  interval: 1m0s
  sourceRef:
    kind: GitRepository
    name: flux-system
  path: ./apps
  prune: true
  validation: client
A
Give the kustomization a recognizable name
B
Tell Flux to poll this every minute
C
Use the apps path in the Git repository




Copy this file to the Git repository directory:


~$cp ~/environment/eks-workshop/modules/automation/gitops/flux/basic/apps.yaml \
  ~/environment/flux/apps.yaml


We'll be installing the application components using their Helm charts, which are published to Amazon ECR Public.


Let's create a HelmRepository resource to tell Flux where to source our charts:


~/environment/eks-workshop/modules/automation/gitops/flux/basic/apps/repository.yaml
apiVersion: source.toolkit.fluxcd.io/v1
kind: HelmRepository
metadata:
  name: retail-store
  namespace: flux-system
spec:
  url: oci://public.ecr.aws/aws-containers
  type: "oci"
  interval: 5m0s
A
The URL of the Helm repository
B
ECR Public hosts Helm charts as OCI artifacts
C
Check for updates every 5 minutes




Copy this file to the Git repository directory:


~$cp ~/environment/eks-workshop/modules/automation/gitops/flux/basic/apps/repository.yaml \
  ~/environment/flux/apps/repository.yaml


Finally we'll tell Flux to install the Helm chart for the ui component:


~/environment/eks-workshop/modules/automation/gitops/flux/basic/apps/ui/helm.yaml
apiVersion: helm.toolkit.fluxcd.io/v2
kind: HelmRelease
metadata:
  name: ui
  namespace: flux-system
spec:
  interval: 10m
  timeout: 5m
  chart:
    spec:
      chart: retail-store-sample-ui-chart
      version: "1.2.1"
      sourceRef:
        kind: HelmRepository
        name: retail-store
      interval: 5m
  releaseName: ui
  install:
    createNamespace: true
  targetNamespace: ui
  values:
    ingress:
      enabled: true
      className: alb
      annotations:
        alb.ingress.kubernetes.io/scheme: internet-facing
        alb.ingress.kubernetes.io/target-type: ip
        alb.ingress.kubernetes.io/healthcheck-path: /actuator/health/liveness
A
The name of the HelmRelease resource
B
The name and version of the chart to install, referencing the Helm repository we specified above
C
Create the namespace if it doesn't exist
D
Configure the chart using values, in this case enabling ingress




Copy the appropriate files to the Git repository directory:


~$cp -R ~/environment/eks-workshop/modules/automation/gitops/flux/basic/apps/ui \
  ~/environment/flux/apps


You Git directory should now look something like this which you can validate by running tree ~/environment/flux:


.
├── apps
│   ├── kustomization.yaml
│   └── ui
│       ├── helm.yaml
│       └── kustomization.yaml
├── apps.yaml
└── flux-system
    ├── gotk-components.yaml
    ├── gotk-sync.yaml
    └── kustomization.yaml


3 directories, 7 files


Finally we can push our configuration to CodeCommit:


~$git -C ~/environment/flux add .
~$git -C ~/environment/flux commit -am "Adding the UI service"
~$git -C ~/environment/flux push origin main


It will take Flux some time to notice the changes in CodeCommit and reconcile. You can use the Flux CLI to watch for our new apps kustomization to appear:


~$flux get kustomization --watch
NAMESPACE     NAME          AGE   READY   STATUS
flux-system   flux-system   14h   True    Applied revision: main/f39f67e6fb870eed5997c65a58c35f8a58515969
flux-system   apps          34s   True    Applied revision: main/f39f67e6fb870eed5997c65a58c35f8a58515969


You can also manually trigger Flux to reconcile like so:


~$flux reconcile source git flux-system -n flux-system


Once apps appears as indicated above use Ctrl+C to close the command. You should now have all the resources related to the UI services deployed once more. To verify, run the following commands:


~$kubectl get deployment -n ui ui
NAME   READY   UP-TO-DATE   AVAILABLE   AGE
ui     1/1     1            1           5m
~$kubectl get pod -n ui
NAME                  READY   STATUS    RESTARTS   AGE
ui-54ff78779b-qnrrc   1/1     Running   0          5m


Get the URL from the Ingress resource:


~$kubectl get ingress -n ui ui -o jsonpath="{.status.loadBalancer.ingress[*].hostname}{'\n'}"
k8s-ui-uinlb-a9797f0f61.elb.us-west-2.amazonaws.com


To wait until the load balancer has finished provisioning you can run this command:


~$wait-for-lb $(kubectl get ingress -n ui ui -o jsonpath="{.status.loadBalancer.ingress[*].hostname}{'\n'}")


And access it in your web browser. You will see the UI from the web store displayed and will be able to navigate around the site as a user.


http://k8s-ui-ui-a9797f0f61.elb.us-west-2.amazonaws.com