Managing secrets with the CloudTruth Argo CD Plugin

Matt Conway

Matt Conway

Co-founder & CTO

Argo CD is a tool that allows you to deploy and manage Kubernetes resources as part of your GitOps workflows. Separating config data from source code is a best practice from Argo and a factor when developing a twelve-factor app. We are going to review how to manage your secrets and config outside of your source code with the CloudTruth Argo CD plugin.

Managing secrets with the Argo CD plugin

The CloudTruth Argo CD plugin will replace secrets and config data within Kubernetes YAML files using <> as a template format. When creating K8s secrets with the plugin, a secrets yaml using stringData would look like the following:

apiVersion: v1
kind: Secret
metadata:
  name: cloudtruth-secret
type: Opaque
stringData:
  password: <cloudtruth-secret>    

The CloudTruth plugin substitutes the value for cloudtruth-secret since it is specified within the <> markers. The value will be retrieved from your CloudTruth organization’s managed vault for the project and environment you specify.

Installing the CloudTruth Argo CD plugin

The first step to managing secrets is installing the CloudTruth Argo CD plugin. We provide a quick getting started script which allows you to specify a set of base CloudTruth Parameters for authentication and config.

curl -s https://raw.githubusercontent.com/cloudtruth/argocd-cloudtruth-plugin/main/install/setup.sh | sh

You can provide the installer with the following parameter values:

ParameterValue
CLOUDTRUTH_API_KEYProvides access to your CloudTruth org
CLOUDTRUTH_ENVIRONMENTSpecifies a targeted Environment
CLOUDTRUTH_PROJECTSpecifies a targeted project
CLOUDTRUTH_TAGSpecifies a targeted tag

The installer will perform the following to configure the plugin in your Argo CD installation:

  1. Create a K8s secret with the provided parameters in the argocd namespace.
  2. Patch the argocd configmap to add CloudTruth to configManamentPlugins
  3. Patch the argocd-repo-server to add the required volumes, secret and init containers.

Using the plugin for secrets and parameters

You can now reference CloudTruth config in your app config files. When creating an application from a Git repository using the Argo CD UI, plugins are enabled from the Directory dropdown.

Configure Argo cd plugin
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Select the argocd-cloudtruth-plugin

Set Argo cd plugin
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Plugin ENV values allow you to override any installation parameter values for your specific app.

Configure Argo cd plugin variables
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Managing secrets demo with the Argo plugin

Here is an example use case with the Argo CD plugin that populates a secret and mounts that secret to a redis pod. The secret value is pulled from CloudTruth.

We will deploy the pod from our demo Git repo.

The secret password substitutes the secret from CloudTruth using the default substitution format <>.

apiVersion: v1
kind: Secret
metadata:
  name: secret-basic-auth
type: kubernetes.io/basic-auth
stringData:
  username: admin
  password: <argo-secret>

You can use the CloudTruth CLI that sets up a project to deploy this example. This creates a project called argocd and creates a secret called argo-secret.

cloudtruth --project argocd set 
cloudtruth --project argocd parameters set argo-secret --value t0p-Secret --secret true

You can use the Argo CLI create command to deploy the app:

argocd app create cloudtruth-secret-management --repo https://github.com/cloudtruth/blog-examples --path argo-secret --dest-server https://kubernetes.default.svc --dest-namespace default --config-management-plugin argocd-cloudtruth-plugin --plugin-env CLOUDTRUTH_ENVIRONMENT=production --plugin-env CLOUDTRUTH_PROJECT=argocd

The argocd app create is broken down into the following commands. The --plugin-env flags specify the CloudTruth environment and project to get values from.

CommandValue
–repohttps://github.com/cloudtruth/blog-examples
–pathargo-secret
–dest-serverhttps://kubernetes.default.svc
–dest-namespacedefault
–config-management-pluginargocd-cloudtruth-plugin
–plugin-envCLOUDTRUTH_ENVIRONMENT=production
–plugin-envCLOUDTRUTH_PROJECT=argocd

Deploy by synching the app:

argocd app sync cloudtruth-secret-management

You can verify the secret value by inspecting the created kubernetes secret or exec into the pod to inspect the secret mounted as a volume.

manage secrets in argo cd app
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The Argo CD UI displays the deployed pod and secret.

argo cd plugin app
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For additional information on the Argo CD plugin you can read the docs and check out our open source repository.