Argo CD Projects and Examples

So far, we have seen about Argo CD applications and CLI with some practical examples. Now lets another interesting feature on Argo CD called, Projects. In this post let’s about Argo CD Projects and how to manage it with example scenarios.

Argo CD Series: https://foxutech.com/category/kubernetes/argocd/

Projects

Projects provide a logical grouping of applications, which is useful when Argo CD is used by multiple teams like Devops, application, etc. Projects provide the following features:

• restrict what may be deployed (trusted Git source repositories)
• restrict where apps may be deployed to (destination clusters and namespaces)
• restrict what kinds of objects may or may not be deployed (e.g., RBAC, CRDs, DaemonSets, NetworkPolicy etc…)
• defining project roles to provide application RBAC (bound to OIDC groups and/or JWT tokens)

By default, argo cd comes with “default” project.

Default Project

Every application belongs to a single project. If unspecified, an application belongs to the default project, which is created automatically and by default, permits deployments from any source repo, to any cluster, and all resource Kinds. The default project can be modified, but not deleted. When initially created, it’s specification is configured to be the most permissive:

spec:
  sourceRepos:
  - '*'
  destinations:
  - namespace: '*'
    server: '*'
  clusterResourceWhitelist:
  - group: '*'
    kind: '*'

Creating Projects

Additional projects can be created to give separate teams different levels of access to namespaces.

We can create the argocd applications declaratively, Cli and webUI. The following command creates a new project project-alpha which can deploy applications to namespace mynamespace of cluster https://kubernetes.default.svc. The permitted Git source repository is set to https://github.com/foxutech/kubernetes.git repository.

# argocd proj create project-alpha -d https://kubernetes.default.svc,mynamespace -s https://github.com/foxutech/kubernetes.git

In this post we will be seeing how to manage via Argo CD CLI, for declarative example. Please check on following video:

Managing Projects

Permitted source Git repositories are managed using commands:

# argocd proj add-source <PROJECT> <REPO>
# argocd proj remove-source <PROJECT> <REPO>

Permitted destination clusters and namespaces are managed with the commands (for clusters always provide server, the name is not used for matching):

# argocd proj add-destination <PROJECT> <CLUSTER>,<NAMESPACE>
# argocd proj remove-destination <PROJECT> <CLUSTER>,<NAMESPACE>

Permitted destination K8s resource kinds are managed with the commands. Note that namespaced-scoped resources are restricted via a deny list, whereas cluster-scoped resources are restricted via allow list.

# argocd proj allow-cluster-resource <PROJECT> <GROUP> <KIND>
# argocd proj allow-namespace-resource <PROJECT> <GROUP> <KIND>
# argocd proj deny-cluster-resource <PROJECT> <GROUP> <KIND>
# argocd proj deny-namespace-resource <PROJECT> <GROUP> <KIND>

Assign Application to Project

The application project can be changed using app set command. In order to change the project of an app, the user must have permissions to access the new project.

# argocd app set application-alpha --project project-alpha

Project Roles

Projects include a feature called roles that enable automated access to a project’s applications. These can be used to give a CI pipeline a restricted set of permissions. For example, a CI system may only be able to sync a single app (but not change its source or destination).

Projects can have multiple roles, and those roles can have different access granted to them. These permissions are called policies, and they are stored within the role as a list of policy strings. A role’s policy can only grant access to that role and are limited to applications within the role’s project. However, the policies have an option for granting wildcard access to any application within a project.

In order to create roles in a project and add policies to a role, a user will need permission to update a project. The following commands can be used to manage a role.

# argocd proj role list
# argocd proj role get
# argocd proj role create
# argocd proj role delete
# argocd proj role add-policy
# argocd proj role remove-policy

Project roles in itself are not useful without generating a token to associate to that role. Argo CD supports JWT tokens as the means to authenticate to a role. Since the JWT token is associated with a role’s policies, any changes to the role’s policies will immediately take effect for that JWT token.

The following commands are used to manage the JWT tokens.

# argocd proj role create-token PROJECT ROLE-NAME
# argocd proj role delete-token PROJECT ROLE-NAME ISSUED-AT

Since the JWT tokens aren’t stored in Argo CD, they can only be retrieved when they are created. A user can leverage them in the cli by either passing them in using the –auth-token flag or setting the ARGOCD_AUTH_TOKEN environment variable. The JWT tokens can be used until they expire or are revoked. The JWT tokens can created with or without an expiration, but the default on the cli is creates them without an expirations date. Even if a token has not expired, it cannot be used if the token has been revoked.

Below is an example of leveraging a JWT token to access a guestbook application. It makes the assumption that the user already has a project named project-alpha and an application called application-alpha.

PROJ=project-alpha
APP=application-alpha
ROLE=get-role
# argocd proj role create $PROJ $ROLE
# argocd proj role create-token $PROJ $ROLE -e 10m
# JWT=<value from command above>
# argocd proj role list $PROJ
# argocd proj role get $PROJ $ROLE

This command will fail because the JWT Token associated with the project role does not have a policy to allow access to the application
# argocd app get $APP --auth-token $JWT

Adding a policy to grant access to the application for the new role
# argocd proj role add-policy $PROJ $ROLE --action get --permission allow --object $APP
# argocd app get $APP --auth-token $JWT

Removing the policy we added and adding one with a wildcard.
# argocd proj role remove-policy $PROJ $ROLE -a get -o $APP
# argocd proj role add-policy $PROJ $ROLE -a get --permission allow -o '*'

The wildcard allows us to access the application due to the wildcard.
# argocd app get $APP --auth-token $JWT
# argocd proj role get $PROJ $ROLE

Revoking the JWT token
# argocd proj role delete-token $PROJ $ROLE <id field from the last command>

This will fail since the JWT Token was deleted for the project role.
# argocd app get $APP --auth-token $JWT

Configuring RBAC With Projects

The project Roles allows configuring RBAC rules scoped to the project. The following sample project provides read-only permissions on project applications to any member of my-oidc-group group.

AppProject example:

apiVersion: argoproj.io/v1alpha1
kind: AppProject
metadata:
  name: my-project
  namespace: argocd
spec:
  roles:
  # A role which provides read-only access to all applications in the project
  - name: read-only
    description: Read-only privileges to my-project
    policies:
    - p, proj:my-project:read-only, applications, get, my-project/*, allow
    groups:
    - my-oidc-group

You can use argocd proj role CLI commands or project details page in the user interface to configure the policy. Note that each project role policy rule must be scoped to that project only. Use the argocd-rbac-cm ConfigMap described in RBAC documentation if you want to configure cross project RBAC rules.

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