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Argo™ CD (preview)

For Elastisys Managed Services Customers

You can order Managed Argo™ CD by filing a service ticket. Here are the highlights:

  • Disaster recovery:
    • Backup scope includes Argo CD resources that can be created by application developers, such as:
      • ApplicationSets
      • Applications
      • AppProjects
      • Secrets and ConfigMaps as needed to store configuration on repositories and notifications.
    • A backup is taken every day between 0:00 am and 6:00 am CET. The backup retention period is 30 days unless otherwise requested by the customer.
    • Recovery time objective (RTO): 4 hours.
  • Monitoring, security patching and incident management: included.

For more information, please read ToS Appendix 3 Managed Additional Service Specification.

This is a preview feature. For more information, please read ToS 9.1 Preview Features.

Important

You cannot ask Argo CD to create a Namespace. This also means that you cannot template the Namespace in ApplicationSets.

Why? See ADR-0042

Argo CD Deployment Model
Argo CD on Welkin Deployment Model
This help you build a mental model of how to levarage Argo CD for deploying your application.

This page will help you succeed in connecting to Argo CD application which meets your security and compliance requirements.

Getting Access

Your administrator will set up the authentication inside Welkin, which will give you access to Argo CD UI.

Secret Management

Secret values should never be stored in plain-text in code repositories. The following sections will describe three supported approaches on how Application Developers can do secret management with Elastisys Managed Argo CD.

With Helm Secrets

Argo CD can be configured to decrypt files encrypted with sops using Helm Secrets. To be able to use Helm-secrets with Argo CD, you will need to contact your Platform Administrator requesting that you want to use this feature and for which OIDC group, users or ServiceAccounts (otherwise the Application Developer group used for accessing the cluster is assumed). Once your Platform Administrator has approved your request, you should be able to create and manage a Kubernetes Secret resource in the argocd-system namespace as instructed below.

The following steps will show how to get started with encrypting files using sops and gpg, storing the encrypted files in a Helm chart, and lastly deploying the Helm chart with Argo CD.

  1. Generate a new GPG key-pair (make sure not to add a passphrase as otherwise Argo CD will not be able to use the key) and then export the private key. The following example will create a GPG key and export the private key to a file named private.asc:

    gpg --batch --rfc4880 --passphrase '' --quick-generate-key "set-me@example.com" default default
fpr=$(gpg --with-colons --list-keys "set-me@example.com" | awk -F: '$1 == "fpr" {print $10; exit}')
gpg --output "private.asc" --armor --export-secret-key $fpr

  2. For Argo CD to be able to use this key for decrypting sops encrypted values files in your Helm charts, you will need to create a Kubernetes Secret in the argocd-system namespace named helm-secrets-private-keys. This Secret will then be mounted and read by the Argo CD repo server. Create the Secret using the private key file created in the previous step:

    PRIVATE_KEY_FILE="private.asc"
kubectl -n argocd-system create secret generic helm-secrets-private-keys --from-file=key.asc=$PRIVATE_KEY_FILE --dry-run=client -oyaml | \
    kubectl label -f- -oyaml argocd.argoproj.io/secret-type=repository --dry-run=client --local | \
    kubectl create -f-

    Deploy the Secret:

    kubectl create -f helm-secrets-private-keys.yaml

    Note

    Once your Platform Administrator has enabled Helm-secrets with Argo CD, the Argo CD repo server Pod will not be able to initialize if this Secret does not exist. Check Pods in the argocd-system namespace after creating the Secret to confirm that the Secret got mounted properly by the repo server:

    $ kubectl get pods -n argocd-system -l app.kubernetes.io/component=repo-server
NAME                                  READY   STATUS    RESTARTS   AGE
argocd-repo-server-77fd58b498-kjm95   1/1     Running   0          3m45s

  3. Create a .sops.yaml file in the Helm chart in which you want to use Helm Secrets. Add your GPG public key to this file. You can get the public key with:

    gpg --list-key "set-me@example.com"

    The .sops.yaml file should look something like this:

    ---
creation_rules:
  - pgp: <public-gpg-key>

  4. Create a values file in your Helm chart repository and put values that should be encrypted into this file:

    touch secrets.yaml

    These values can then be referenced in templates as any other Helm values.

  5. Encrypt the values file using sops (as long as there is a .sops.yaml file in the same folder containing your public GPG key you do not have to specify the GPG key when running the following command):

    sops --encrypt --in-place secrets.yaml

    To test using the now encrypted secrets.yaml file together with the Helm chart, install the Helm Secrets plugin, and then run the following from the root folder of the Helm chart to template the Helm chart:

    helm template . --values secrets://secrets.yaml

  6. The file secrets.yaml can now safely be stored in a code repository as long as it is encrypted.

    Tip

    To edit values in the encrypted values file, you can use sops which will open the file in clear text in a configured editor:

    sops secrets.yaml

    There is also a VSCode plugin which can simplify editing sops encrypted files directly in the VSCode editor.

    Tip

    Add a pre-commit hook to ensure to not push files containing sensitive data that are not encrypted with sops.

  7. In Argo CD, when you create your Application, add the secret values file (secrets.yaml) as follow:

    argocd-helm-secrets

    Here, secrets.yaml is the relative path and name of the file containing encrypted values.

With SealedSecrets

The following steps assumes SealedSecrets is installed in the cluster. For installing SealedSecrets in a Welkin cluster, refer to the self-managed guide. You will need to contact your Platform Administrator requesting that you want to use SealedSecrets together with Argo CD.

  1. Create a SealedSecret, the following steps will create a SealedSecret for the namespace in the current Kubernetes context:

    export SEALED_SECRETS_CONTROLLER_NAMESPACE=sealed-secrets # set this to the namespace in which the controller is running in
export SECRET_VALUE=<secret-data> # this will be a value that should be encrypted/sealed
export KEY=foo # the key used for referencing SECRET_VALUE in the secret

kubectl create secret generic mysecret --dry-run=client --from-literal=$KEY=$SECRET_VALUE -o yaml | \
    kubeseal --format yaml > mysealedsecret.yaml

    Note

    With SealedSecrets it is possible to set a scope of a Secret. By default this scope is set to strict in which the SealedSecret controller uses the name and namespace of the Secret as attributes during encryption, hence, the SealedSecret needs to be created with the same values for these attributes if the controller is to be able to decrypt the SealedSecret. It is possible to change the scope with the --scope flag for kubeseal, refer to the official documentation for SealedSecrets for possible scopes.

  2. The generated SealedSecret manifest file mysealedsecret.yaml will contain the encrypted $SECRET_VALUE and is safe to store on, for example, GitHub. Push this manifest file to the repository containing the rest of your application manifests.

  3. Deploy the application containing the SealedSecret with Argo CD as any other application.

Using vals with HashiCorp's Vault

If you want to use vals with Vault, you will need to contact your Platform Administrator requesting that you want to use vals with Vault together with Argo CD.

  1. Create a Secret in the argocd-system namespace called vals-secret:

    apiVersion: v1
kind: Secret
metadata:
  name: vals-secret
  namespace: argocd-system
  labels:
    argocd.argoproj.io/secret-type: vals-secret
type: Opaque
data:
  VAULT_ADDR: ""
  VAULT_NAMESPACE: ""
  VAULT_AUTH_METHOD: ""
  VAULT_ROLE_ID: ""
  VAULT_SECRET_ID: ""
  VAULT_TOKEN: ""

    Fill out required data in secret to connect it to your Vault.

    Note

    When encoding your data, make sure to use echo -n <data> | base64 to avoid adding a new line at the end of your encoded secret.

  2. Contact your Platform Administrator to restart the argocd-repo-server. It is needed to load your secret environment variables so that Argo CD can connect to your Vault.

  3. Argo CD should now be able to connect to your Vault, to replace a value with a secret from your Vault, use the following syntax:

    secrets+literal://vals!ref+vault://path/to/#/secret

    Here's an example of an Argo CD Application manifest:

    apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: argocd-application
  namespace: argocd-system
  finalizers:
    - resources-finalizer.argocd.argoproj.io
spec:
  destination:
    namespace: staging
    server: https://kubernetes.default.svc
  project: default
  source:
    helm:
      valueFiles:
        - values.yaml
      fileParameters:
        - name: password
          path: secrets+literal://vals!ref+vault://secret/user/#/password
    path: deploy/helm/app
    repoURL: https://github.com/username/repository.git
    targetRevision: HEAD
  syncPolicy:
    automated:
      prune: true
      selfHeal: true

Argo CD Notifications

Argo CD Notifications continuously monitors Argo CD applications and provides a flexible way to notify users about important changes in the application state. Using a flexible mechanism of triggers and templates you can configure when the notification should be sent as well as notification content.

To configure Argo CD notifications, make sure you are allowed to update the current Kubernetes objects:

  • secret/argocd-notifications-secret
  • configmap/argocd-notifications-cm

For Elastisys Managed Argo CD, you should be able to modify those objects if you belong to any customer admin group, or if you are a customer admin user.

In case you're not, ask your Platform Administrator to add you accordingly.

Triggers & Templates

The trigger defines the condition when the notification should be sent. The definition includes name, condition and notification templates reference.

The notification template is used to generate the notification content. Templates are meant to be reusable and can be referenced by multiple triggers.

Both triggers & notification templates can be configured in argocd-notifications-cm ConfigMap.

Argo CD Notifications includes the catalog of useful triggers and templates. So you can just use them instead of reinventing new ones.

Note

The catalog triggers and templates can be found in the argocd-notifications-cm ConfigMap.

$ kubectl edit cm/argocd-notifications-cm -n argocd-system

If you don't have any triggers or templates defined, you can add the catalog template and trigger definitions

apiVersion: v1
kind: ConfigMap
metadata:
name: argocd-notifications-cm
data:
    context: |
        argocdUrl: "https://argocd.example.com"
    template.app-deployed: |
        ...
    template.app-health-degraded: |
        ...
    template.app-sync-failed: |
        ...
    template.app-sync-running: |
        ...
    template.app-sync-status-unknown: |
        ...
    template.app-sync-succeeded: |
        ...
    trigger.on-deployed: |
        ...
    trigger.on-sync-failed: |
        ...
    trigger.on-sync-running: |
        ...
    trigger.on-sync-status-unknown: |
        ...
    trigger.on-sync-succeeded: |
        ...

Notification Services

The notification services represent integration with services such as Slack, email or custom webhook. Services are configured in argocd-notifications-cm ConfigMap using service.<type>.(<custom-name>) keys and might reference sensitive data from argocd-notifications-secret Secret.

Argo CD Notifications support multiple service types, and provide detailed steps on how to configure each service. To learn more, see Notification services.

Subscriptions

The subscription to Argo CD application events can be defined using notifications.argoproj.io/subscribe.<trigger>.<service>: <recipient> annotation. For example, the following annotation subscribes two Slack channels to notifications about every successful synchronization of the Argo CD application:

kubectl edit Application my-argo-application

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-argo-application
  annotations:
    notifications.argoproj.io/subscribe.on-sync-succeeded.slack: my-channel1;my-channel2

Example

To configure Email service for example:

  1. Add email username and password token to argocd-notifications-secret Secret

    echo -n "sender@example.com" | base64 -w0 # c2VuZGVyQGV4YW1wbGUuY29t
echo -n "secretPassword" | base64 -w0 #  c2VjcmV0UGFzc3dvcmQ=
kubectl edit -n argocd-system argocd-notifications-secret

    apiVersion: v1
kind: Secret
metadata:
  name: argocd-notifications-secret
  namespace: argocd-system
data:
  email-username: c2VuZGVyQGV4YW1wbGUuY29t
  email-password: c2VjcmV0UGFzc3dvcmQ=

  2. Register Email notification service

    kubectl edit -n argocd-system argocd-notifications-cm

    Add the service under the ConfigMap data

    apiVersion: v1
kind: ConfigMap
metadata:
  name: argocd-notifications-cm
data:
  service.email.gmail: |
    username: $email-username
    password: $email-password
    host: smtp.gmail.com
    port: 465
    from: $email-username

    In case you want to use a separate SMTP server instead of gmail

    apiVersion: v1
kind: ConfigMap
metadata:
  name: argocd-notifications-cm
data:
  service.email.custom: |
    username: $email-username
    password: $email-password
    host: smtp.custom.com
    port: 587
    from: $email-username

  3. Subscribe to notifications by adding the notifications.argoproj.io/subscribe.on-sync-succeeded.gmail annotation to the Argo CD application:

    kubectl patch app my-argo-application -p '{"metadata": {"annotations": {"notifications.argoproj.io/subscribe.on-sync-succeeded.gmail":"receiver@example.com"}}}' --type merge

Now, if we try syncing an application, we will get the notification once sync is completed.

Note

Email notification will not work if the sender has 2FA enabled.

Restrictions

Example error:

Failed to load live state: Cluster level Namespace "application" can not be managed when in namespaced mode

Our Argo CD installation is using the namespaced method. This means that Argo CD has access to Roles with permissions to CRUD on objects in the inclusion list. It has a list of namespaces that it can look at and reconcile things every few seconds. Any feature that requires Argo CD cluster-wide installation will not be supported with our offering.

The reason for this choice is that, according to the Welkin mission and vision, the platform should make it hard for Application Developers to do the wrong thing by employing safeguards and secure defaults. With this configuration, we prevent Argo CD from having access to objects in the inclusions list across the entire cluster. This prevents objects from being deployed into namespaces owned by the Platform Administrator, which could compromise platform security and stability. For example, this choice adds another layer of protection, preventing the Application Developer from interfering with backups. Read more about it here.

Argo CD is not allowed to manage its own namespace. This means that features such as Apps of Apps does not work by default. Read more about the decision here.

Apps of Apps (preview)

This is a preview feature. For more information, please read ToS 9.1 Preview Features.

Using Apps of Apps with our offering is currently a preview feature, and customers can request it, provided they accept risks such as:

  • When Apps-of-Apps is enabled, we will not be able to provide Uptime SLAs for you on the Argo Endpoint (This will be a best effort support even in future premium environments, unless the Argo project develops the feature upstream in a more secure and isolated way)

  • Apps-of-Apps will currently be regarded as a preview feature and, as such, we reserve the right to disable it if it interferes with our OPS policies/practices – should that unfortunate event happen, it will be in dialogue with the customer.

Argo CD cannot create HNC namespaces and deploy services into them. This means that as an Application Developer you cannot template the namespace as a value in a manifest. As an Application Developer you need to create subnamespaces manually and deploy applications into it. Read more about the decision here.

Known Issues

  • With Argo CD CLI access granted, an issue authenticating via Dex can occur and you will see an error message of

failed to get token: oauth2: "invalid_client” “Invalid client credentials."

This is a known issue in Argo CD and the progress for it can be tracked here. Sometimes, when encountering this login issue, opening a new tab and re-trying the login process after entering the Argo CD homepage URL can resolve the problem.

Follow the Go-Live Checklist

You should be all set. Before going into production, don't forget to go through the go-live checklist.

Welkin Argo CD Release Notes

Check out the release notes for the Argo CD setup that runs in Welkin environments!

Further Reading