flux tutorial
=============

Like the tutorials in [flux-01]_ and [flux-02]_, this sets up a repository
for flux and deploys podinfo, but with the following differences:

- Repositories are in gitlab
- The podinfo repository is private


Install flux and create a kubernetes cluster
--------------------------------------------

- Install flux with brew (macOS):

   .. code-block:: fish

      brew install fluxcd/tap/flux

- Add flux completion to fish (ref. https://fluxcd.io/docs/cmd/flux_completion_fish/ )

- Create a kubernetes cluster (for Digital Ocean ref. https://docs.digitalocean.com/products/kubernetes/how-to/create-clusters/ )

- Update kubeconfig to use created cluster (https://docs.digitalocean.com/products/kubernetes/how-to/connect-to-cluster/ )

- Check flux pre-req:

   .. code-block:: fish

      > flux check --pre
      ► checking prerequisites
      ✔ kubectl 1.21.0 >=1.18.0-0
      ✔ Kubernetes 1.21.2 >=1.16.0-0
      ✔ prerequisites checks passed


Bootstrap flux 
--------------

- Run flux bootstrap command

   .. code-block:: fish
      
      > flux bootstrap gitlab \
         --ssh-hostname=gitlab.com \
         --owner=your_gitlab_user --personal \
         --repository=flux-test \
         --branch=master \
         --path=clusters/my-cluster

      ► connecting to https://gitlab.com
      ...
      ✔ all components are healthy


Deploy podinfo (from a private repo)
--------------

- Fork podinfo to a private repo (e.g., https://gitlab.com/your_gitlab_user/podinfo)

- Clone bootstrapped flux repository

- Create source git repository manifest for podinfo

      .. code-block:: fish

         flux-test (master)> flux create source git podinfo \
            --url=https://gitlab.com/your_gitlab_user/podinfo \
            --branch=master \
            --interval=30s \
            --export > ./clusters/my-cluster/podinfo-source.yaml

- Because the podinfo repo is private, fix the url and add a secretRef in
  the GitRepository manifest:
  From: 

      .. code-block:: yaml

         ---
         apiVersion: source.toolkit.fluxcd.io/v1beta1
         kind: GitRepository
         metadata:
         name: podinfo
         namespace: flux-system
         spec:
         interval: 30s
         ref:
            branch: master
         url: https://gitlab.com/your_gitlab_user/podinfo


  To:

      .. code-block:: yaml

         ---
         apiVersion: source.toolkit.fluxcd.io/v1beta1
         kind: GitRepository
         metadata:
         name: podinfo
         namespace: flux-system
         spec:
         interval: 30s
         ref:
            branch: master
         url: ssh://git@gitlab.com/your_gitlab_user/podinfo
         secretRef:
            name: flux-system


- Create kustomization for podinfo

   .. code-block:: fish


      flux-test (master)> flux create kustomization podinfo \
         --source=podinfo \
         --path="./kustomize" \
         --prune=true \
         --validation=client \
         --interval=5m \
         --export > ./clusters/my-cluster/podinfo-kustomization.yaml

- Commit and push

- Check flux logs and get kustomizations

   .. code-block:: fish

      > flux logs --kind=Kustomization --name=podinfo

      > flux get kustomizations


- Forward port to access the application

   .. code-block:: fish

      > kubectl get deployments,svc
      NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
      deployment.apps/podinfo   2/2     2            2           5m25s

      NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)             AGE
      service/kubernetes   ClusterIP   10.245.0.1      <none>        443/TCP             3d
      service/podinfo      ClusterIP   10.245.150.90   <none>        9898/TCP,9999/TCP   5m25s

      > kubectl port-forward service/podinfo :9898
      Forwarding from 127.0.0.1:65326 -> 9898
      Forwarding from [::1]:65326 -> 9898

- Access port with a web browser http://localhost:65326


References
----------

.. [flux-01] `Get Started with Flux (fluxcd.io)
   <https://fluxcd.io/docs/get-started/>`_
   (Retrieved 2021-07-29)

.. [flux-02] `How To Set Up a Continuous Delivery Pipeline with Flux on DigitalOcean Kubernetes (digitalocean.com)
   <https://www.digitalocean.com/community/tutorials/how-to-set-up-a-continuous-delivery-pipeline-with-flux-on-digitalocean-kubernetes>`_
   (Retrieved 2021-07-29)