ArgoCD Basics Training on ArgoCD Techlab

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Mon, 01 Jan 0001 00:00:00 +0000

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Mon, 01 Jan 0001 00:00:00 +0000

- acend gmbh

5.1 Helm

Mon, 01 Jan 0001 00:00:00 +0000

This lab explains how to use Helm as manifest format together with Argo CD.

Helm Introduction

Helm is a Cloud Native Foundation project to define, install and manage applications in Kubernetes.

It can be used to package multiple Kubernetes resources into a single logical deployment unit.

Helm Charts are configured using values.yaml files. (e.g. images, image tags, hostnames, …).

When using helm charts together with Argo CD we can specify the values.yaml like this:

5.2 Kustomize

Mon, 01 Jan 0001 00:00:00 +0000

This lab explains how to use kustomize as manifest format together with Argo CD.

Kustomize Introduction

Kustomize introduces a template-free way to customize application configuration that simplifies the use of off-the-shelf applications. It is built into kubectl and oc with the command kubectl apply -k or oc apply -k.

It uses a concept called overlays, which allows to reduce redundant configuration for multiple stages (e.g. dev, prod, test) without a use of a template language.

5.3 Jsonnet (Optional)

Mon, 01 Jan 0001 00:00:00 +0000

This lab explains how to use jsonnet as manifest format together with Argo CD.

Jsonnet

Jsonnet is a templating language which adds the possibility to programmatically work with the underlying data. It basically is a simple extension of JSON .

Let’s have a look at an example first. The following jsonnet file

{
 application1: {
 name: "jsonnet-application1",
 basepath: "/application/test",
 path: self.basepath + "/" + self.name,
 },
 application2: self.application1 { name: "jsonnet-application2" },
}

will render into:

{
 "application1": {
 "basepath": "/application/test",
 "name": "jsonnet-application1",
 "path": "/application/test/jsonnet-application1"
 },
 "application2": {
 "basepath": "/application/test",
 "name": "jsonnet-application2",
 "path": "/application/test/jsonnet-application2"
 }
}

Among many other features, Jsonnet can help to reduce duplications.

8.1 Tracking and Deployment Strategies

Mon, 01 Jan 0001 00:00:00 +0000

If you are using ArgoCD with Git or Helm tools, ArgoCD gives you the availability to configure different tracking and deployment strategies.

Helm

For Helm you can use Semver versions either to pin to a specific version or to track minor / patch changes.

Use Case	How	Examples
Pin to a version (e.g. in production)	Use the version number	1.2.0
Track patches (e.g. in pre-production)	Use a range	1.2.* or >=1.2.0 <1.3.0
Track minor releases (e.g. in QA)	Use a range	1.* or >=1.0.0 <2.0.0
Use the latest (e.g. in local development)	Use star range	* or >=0.0.0

Git

Use Case	How	Notes
Pin to a version (e.g. in production)	Either tag the commit with (e.g. v1.2.0) and use that tag, or using commit SHA.	See commit and version pinning.
Use the latest (e.g. in local development)	Use HEAD or master (assuming master is your master branch).	See HEAD / Branch Tracking

Head / Branch Tracking

Either a branch name or a symbolic reference (like HEAD). For branches ArgoCD will take the latest commit of this branch. This method is often used in development environment where you want to apply the latest changes.

8.2 Sync Windows

Mon, 01 Jan 0001 00:00:00 +0000

With Sync windows the user can define at which time applications can be synchronized automatically and manually by Argo CD. Allowed and forbidden time windows can be defined. Sync windows can be restricted to a subset of applications, clusters and namespaces and thus offer great flexibility.

Task 8.2.1: Create application and project

Now we want to create a new empty Argo CD project.

argocd proj create -s "*" -d "*,*" project-sync-windows-$USER
argocd app create sync-windows-$USER --repo https://github.com/acend/argocd-training-examples.git --path 'example-app' --dest-server https://kubernetes.default.svc --dest-namespace $USER --project project-sync-windows-$USER
argocd app sync sync-windows-$USER

You should see the following message after a successful sync

6.1 App of Apps

Mon, 01 Jan 0001 00:00:00 +0000

The App of apps pattern is a declarative specification of one ArgoCD app that consists only of other ArgoCD applications. This way we have the possibility to deploy multiple apps within just one single App definition.

In Lab 2.7 you learnt how ArgoCD stores its state as Application Custom Resources. The basic idea behind the App of Apps pattern therefore is to store those Application Custom Resources within an Argo CD Application.

6.2 Application Sets

Mon, 01 Jan 0001 00:00:00 +0000

With the ApplicationSet ArgoCD adds support for managing ArgoCD Application across a large number of clusters and environments. Plus it adds the capability of managing multitenant Kubernetes clusters.

ApplicationSets are defined through Custom Resource Definition and are processed by the ApplicationSet controller.

The ApplicationSet provides following features

The ability to use a single Kubernetes manifest to target multiple Kubernetes clusters with Argo CD
The ability to use a single Kubernetes manifest to deploy multiple applications from one or multiple Git repositories with Argo CD
Improved support for monorepos: in the context of Argo CD, a monorepo is multiple Argo CD Application resources defined within a single Git repository
Within multitenant clusters, improves the ability of individual cluster tenants to deploy applications using Argo CD (without needing to involve privileged cluster administrators in enabling the destination clusters/namespaces)

A list of parameters, which come from so called generators , render the ArgoCD Application Template to create a list of Applications.

9.1 Orphaned Resources

Mon, 01 Jan 0001 00:00:00 +0000

This lab contains demonstrates how to find orphaned top-level resources with Argo CD. Orphaned resources are not managed by Argo CD and could be potentially removed from cluster.

Task 9.1.1: Create application and project

argocd app create argo-$USER --repo https://github.com/acend/argocd-training-examples.git --path 'example-app' --dest-server https://kubernetes.default.svc --dest-namespace $USER
argocd app sync argo-$USER

Create new Argo CD project without restrictions for Git source repository (–src) nor destination cluster/namespace (–dest)

argocd proj create --src "*" --dest "*,*" apps-$USER

Enable visualization and monitoring of Orphaned Resources for the newly created project apps-<username>

9.2 Backup and Restore

Mon, 01 Jan 0001 00:00:00 +0000

Warning

This Lab only works on your local machine.

Backup and Restore

As ArgoCD holds the whole state in native Kubernetes objects it’s quite straightforward to make a backup and restore it in case of a disaster recovery.

ArgoCD provides the utility argocd-util which is used by ArgoCD internally. The functions export and import can be used for backup and restore of a ArgoCD instance.

As the tool is contained inside the ArgoCD server image you just can execute it from inside the container.