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Lab 3 - Implement GitOps

Crossplane and ArgoCD

GitOps is a set of practices to manage infrastructure and application configurations using Git, an open source version control system. GitOps works by using Git as a single source of truth for declarative infrastructure and applications. The Git repository contains the entire state of the system so that the trail of changes to the system state are visible and auditable.

Using GitOps tool such as Argo CD or Flux CD, we will be able to make our target system match the desired state that is coded in the Git repository. So when we will deploy new resources or update an existing ones, after updating the repository the automated process will apply the changes.

In the last laboratory, we will apply this concepts to deploy our infrastructure using Crossplane and Argo CD without human intervention.

Info

If you want to know more about Gitops and Argo CD, please read my article From GIT to Kubernetes in 10 minutes with ArgoCD.

1. Creating IaC repository

As said before, a Git will be our source of truth for our infrastructure and will contain the entire state and history of it. So that the trail of changes to the system state are visible and auditable.

1.1. Create a Github repository

First thing to do is to create a Git repository that we will use to store the Crosplanes files.

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gh repo create --public acw-crossplane-with-argocd --clone --gitignore Python

cd acw-crossplane-with-argocd

1.2. Add Crossplane resources

Next, we have to add the yaml files containing the Crossplain resources. However, we will not push the changes to the repository.

Tip

In this case, we have to add argocd.argoproj.io/sync-wave and argocd.argoproj.io/sync-options annotations that will indicate ArgoCD the order of execution so claim must execute only after XD resources are created. See Sync Phases and Waves and Skip Dry Run for new custom resources types for more information.

  • Create a CompositeResourceDefinition file.

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    cat > 1_definition.yaml <<EOF
apiVersion: apiextensions.crossplane.io/v1
kind: CompositeResourceDefinition
metadata:
    name: xdostorages.storage.acw.alvsanand.github.io
    annotations:
        argocd.argoproj.io/sync-wave: "1"
spec:
    group: storage.acw.alvsanand.github.io
    names:
        kind: XDObjectStorage
        plural: xdostorages
    claimNames:
        kind: ObjectStorage
        plural: ostorages
    versions:
        - name: v1alpha1
          served: true
          referenceable: true
          schema:
              openAPIV3Schema:
                  type: object
                  properties:
                      spec:
                          type: object
                          properties:
                              parameters:
                                  type: object
                                  properties:
                                      storageName:
                                          type: string
                                  required:
                                      - storageName
                          required:
                              - parameters
EOF

  • Create a Composition file.

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    cat > 1_composition.yaml <<EOF
apiVersion: apiextensions.crossplane.io/v1
kind: Composition
metadata:
    name: xdostorages.aws.storage.acw.alvsanand.github.io
    labels:
        serviceType: storage
        provider: aws
    annotations:
        argocd.argoproj.io/sync-wave: "1"
spec:
    compositeTypeRef:
        apiVersion: storage.acw.alvsanand.github.io/v1alpha1
        kind: XDObjectStorage
    resources:
        - name: s3bucket
          base:
              apiVersion: s3.aws.crossplane.io/v1beta1
              kind: Bucket
              spec:
                  forProvider:
                      acl: public-read-write
                      locationConstraint: us-east-1
                  providerConfigRef:
                      name: default
          patches:
              - fromFieldPath: "spec.parameters.storageName"
                toFieldPath: "metadata.name"
                transforms:
                    - type: string
                      string:
                          fmt: "%s-acw"
EOF

  • Create a Claim file.

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    cat > 2_claim.yaml <<EOF
apiVersion: storage.acw.alvsanand.github.io/v1alpha1
kind: XDObjectStorage
metadata:
    name: some-bucket
    namespace: default
    annotations:
        argocd.argoproj.io/sync-wave: "2"
        argocd.argoproj.io/sync-options: SkipDryRunOnMissingResource=true
spec:
    compositionSelector:
        matchLabels:
            provider: aws
    parameters:
        storageName: some-bucket
EOF

2. Create an App in ArgoCD

After the repository is created, we should create an Application in ArgoCD. Therefore, ArgoCD will sync the Crossplane resources will the state stored in the repository. However, having the repository with no files will not create any resources.

  • Obtain HTTPS url of the GIT repository.

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    HTTPS_REPO_URL=$(git remote show origin |  sed -nr 's/.+Fetch URL: git@(.+):(.+).git/https:\/\/\1\/\2.git/p')

  • Create a new Application in auto mode and listening to the master.

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    cat <<EOF | kubectl apply -f -
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: acw-storage
  namespace: argocd
spec:
  project: default
  source:
    repoURL: $HTTPS_REPO_URL
    targetRevision: main
    path: .
  destination:
    server: https://kubernetes.default.svc
    namespace: apify-your-infra-with-crossplane
  syncPolicy:
    automated: {}
EOF

  • Wait until the application is sync.

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    kubectl get applications -n argocd acw-storage

...    
NAME          SYNC STATUS   HEALTH STATUS
acw-storage   Synced        Healthy

  • Furthermore, you can check in ArgoCD UI the status of the application.

ArgoCD - Application Empty

3. Commit changes to Github

After ArgoCD is ready to watch for changes, we will push the files to the repo in order to force the deployment.

  • Add files and generate a commit.

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    git add *.yaml
git commit -m "Added Crossplane files"

  • Push changes to Github.

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    git push --set-upstream origin main

4. Wait for ArgoCD to sync

Now that the changes are in Git, ArgoCD will detect the chances and sync our infrastructure to match the state of the repository.

  • Wait some minutes until the application is synced.

ArgoCD - Application Syncing

  • After the sync is completed, you can check the application status.

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    kubectl describe applications -n argocd acw-storage

...    
Name:         acw-storage
Namespace:    argocd
Labels:       <none>
Annotations:  <none>
API Version:  argoproj.io/v1alpha1
Kind:         Application
Metadata:
  Creation Timestamp:  2022-01-07T12:51:44Z
  Generation:          12
  Managed Fields:
    API Version:  argoproj.io/v1alpha1
    Fields Type:  FieldsV1
    fieldsV1:
      f:metadata:
        f:annotations:
          .:
          f:kubectl.kubernetes.io/last-applied-configuration:
      f:spec:
        .:
        f:destination:
          .:
          f:namespace:
          f:server:
        f:project:
        f:source:
          .:
          f:path:
          f:repoURL:
          f:targetRevision:
        f:syncPolicy:
          .:
          f:automated:
    Manager:      kubectl-client-side-apply
    Operation:    Update
    Time:         2022-01-07T12:51:44Z
    API Version:  argoproj.io/v1alpha1
    Fields Type:  FieldsV1
    fieldsV1:
      f:status:
        .:
        f:health:
          .:
          f:status:
        f:history:
        f:operationState:
          .:
          f:finishedAt:
          f:message:
          f:operation:
            .:
            f:initiatedBy:
              .:
              f:automated:
            f:retry:
              .:
              f:limit:
            f:sync:
              .:
              f:revision:
          f:phase:
          f:startedAt:
          f:syncResult:
            .:
            f:resources:
            f:revision:
            f:source:
              .:
              f:path:
              f:repoURL:
              f:targetRevision:
        f:reconciledAt:
        f:resources:
        f:sourceType:
        f:summary:
        f:sync:
          .:
          f:comparedTo:
            .:
            f:destination:
              .:
              f:namespace:
              f:server:
            f:source:
              .:
              f:path:
              f:repoURL:
              f:targetRevision:
          f:revision:
          f:status:
    Manager:         argocd-application-controller
    Operation:       Update
    Time:            2022-01-07T12:51:52Z
  Resource Version:  27693
  UID:               24016e22-b199-4ed4-9f2b-6ce96018f798
Spec:
  Destination:
    Namespace:  apify-your-infra-with-crossplane
    Server:     https://kubernetes.default.svc
  Project:      default
  Source:
    Path:             .
    Repo URL:         https://github.com/alvsanand/acw-crossplane-with-argocd.git
    Target Revision:  main
  Sync Policy:
    Automated:
Status:
  Health:
    Status:  Healthy
  History:
    Deploy Started At:  2022-01-07T12:51:45Z
    Deployed At:        2022-01-07T12:51:52Z
    Id:                 0
    Revision:           2d55ed389750624c21bce8c2d534f4b77d72f837
    Source:
      Path:             .
      Repo URL:         https://github.com/alvsanand/acw-crossplane-with-argocd.git
      Target Revision:  main
  Operation State:
    Finished At:  2022-01-07T12:51:52Z
    Message:      successfully synced (all tasks run)
    Operation:
      Initiated By:
        Automated:  true
      Retry:
        Limit:  5
      Sync:
        Revision:  2d55ed389750624c21bce8c2d534f4b77d72f837
    Phase:         Succeeded
    Started At:    2022-01-07T12:51:45Z
    Sync Result:
      Resources:
        Group:       apiextensions.crossplane.io
        Hook Phase:  Succeeded
        Kind:        Composition
        Message:     composition.apiextensions.crossplane.io/xdostorages.aws.storage.acw.alvsanand.github.io created
        Name:        xdostorages.aws.storage.acw.alvsanand.github.io
        Namespace:   apify-your-infra-with-crossplane
        Status:      Synced
        Sync Phase:  Sync
        Version:     v1
        Group:       apiextensions.crossplane.io
        Hook Phase:  Succeeded
        Kind:        CompositeResourceDefinition
        Message:     compositeresourcedefinition.apiextensions.crossplane.io/xdostorages.storage.acw.alvsanand.github.io created
        Name:        xdostorages.storage.acw.alvsanand.github.io
        Namespace:   apify-your-infra-with-crossplane
        Status:      Synced
        Sync Phase:  Sync
        Version:     v1
        Group:       storage.acw.alvsanand.github.io
        Hook Phase:  Running
        Kind:        XDObjectStorage
        Message:     xdobjectstorage.storage.acw.alvsanand.github.io/some-bucket created
        Name:        some-bucket
        Namespace:   apify-your-infra-with-crossplane
        Status:      Synced
        Sync Phase:  Sync
        Version:     v1alpha1
      Revision:      2d55ed389750624c21bce8c2d534f4b77d72f837
      Source:
        Path:             .
        Repo URL:         https://github.com/alvsanand/acw-crossplane-with-argocd.git
        Target Revision:  main
  Reconciled At:          2022-01-07T12:51:52Z
  Resources:
    Group:      apiextensions.crossplane.io
    Kind:       CompositeResourceDefinition
    Name:       xdostorages.storage.acw.alvsanand.github.io
    Status:     Synced
    Version:    v1
    Group:      apiextensions.crossplane.io
    Kind:       Composition
    Name:       xdostorages.aws.storage.acw.alvsanand.github.io
    Status:     Synced
    Version:    v1
    Group:      storage.acw.alvsanand.github.io
    Kind:       XDObjectStorage
    Name:       some-bucket
    Status:     Synced
    Version:    v1alpha1
  Source Type:  Directory
  Summary:
  Sync:
    Compared To:
      Destination:
        Namespace:  apify-your-infra-with-crossplane
        Server:     https://kubernetes.default.svc
      Source:
        Path:             .
        Repo URL:         https://github.com/alvsanand/acw-crossplane-with-argocd.git
        Target Revision:  main
    Revision:             2d55ed389750624c21bce8c2d534f4b77d72f837
    Status:               Synced
Events:
  Type    Reason              Age    From                           Message
  ----    ------              ----   ----                           -------
  Normal  OperationStarted    4m34s  argocd-application-controller  Initiated automated sync to '2d55ed389750624c21bce8c2d534f4b77d72f837'
  Normal  ResourceUpdated     4m34s  argocd-application-controller  Updated sync status:  -> OutOfSync
  Normal  ResourceUpdated     4m34s  argocd-application-controller  Updated health status:  -> Healthy
  Normal  ResourceUpdated     4m33s  argocd-application-controller  Updated sync status:  -> OutOfSync
  Normal  ResourceUpdated     4m33s  argocd-application-controller  Updated health status:  -> Healthy
  Normal  OperationCompleted  4m27s  argocd-application-controller  Sync operation to 2d55ed389750624c21bce8c2d534f4b77d72f837 succeeded
  Normal  ResourceUpdated     4m27s  argocd-application-controller  Updated sync status: OutOfSync -> Synced

  • Finally, you can check in ArgoCD UI the status of the application.

ArgoCD - Application Synced

  • Check that the xdostorages is created.

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    kubectl get xdostorages

...
NAME          READY   COMPOSITION                                       AGE
some-bucket   True    xdostorages.aws.storage.acw.alvsanand.github.io   89s

  • Check that the bucket object is created.

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    kubectl get bucket

...
NAME              READY   SYNCED   AGE
some-bucket-acw   True    True     113s

  • Check that the bucket has been created in LocalStack.

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    awslocal s3api list-buckets

...
{
    "Buckets": [
        {
            "Name": "some-bucket-acw",
            "CreationDate": "2022-01-06T08:05:16.000Z"
        }
    ],
    "Owner": {
        "DisplayName": "webfile",
        "ID": "bcaf1ffd86f41161ca5fb16fd081034f"
    }
}

5. Cleanup the laboratory

Last step, delete all resources created. In this case, we should delete the application and ArgoCD will delete the resources created with it.

  • Delete the application.

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    kubectl delete application -n argocd acw-storage

  • Check that the bucket has been created in LocalStack.

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    awslocal s3api list-buckets

...
{
    "Buckets": [],
    "Owner": {
        "DisplayName": "webfile",
        "ID": "bcaf1ffd86f41161ca5fb16fd081034f"
    }
}
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