GitOps with ArgoCD in Kubernetes - Step-by-Step Execution

Process Flow - GitOps with ArgoCD

Developer pushes code to Git repo

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ArgoCD monitors Git repo

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Detects changes in repo

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ArgoCD syncs changes to Kubernetes cluster

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Kubernetes applies new config/state

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Cluster state matches Git repo state

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ArgoCD reports status back

This flow shows how ArgoCD watches a Git repository for changes, then applies those changes automatically to a Kubernetes cluster, keeping cluster state in sync with Git.

Execution Sample

Kubernetes

kubectl create namespace argocd
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml
argocd app create guestbook --repo https://github.com/argoproj/argocd-example-apps.git --path guestbook --dest-server https://kubernetes.default.svc --dest-namespace default
argocd app sync guestbook

This sequence installs ArgoCD, creates an application linked to a Git repo, and syncs it to the Kubernetes cluster.

Process Table

Step	Action	Evaluation	Result
1	Create namespace 'argocd'	Namespace 'argocd' does not exist	Namespace 'argocd' created
2	Apply ArgoCD manifests	Manifests valid	ArgoCD components deployed in 'argocd' namespace
3	Create ArgoCD app 'guestbook'	Repo and path accessible	App 'guestbook' registered in ArgoCD
4	ArgoCD monitors Git repo	No changes yet	App status: Synced
5	Push change to Git repo (e.g., update guestbook image)	Change detected by ArgoCD	App status: OutOfSync
6	Run 'argocd app sync guestbook'	Sync command accepted	Cluster updated to match Git repo
7	Verify app status	Cluster matches Git repo	App status: Synced
8	Exit	No further changes	Process waits for next Git change

💡 No new changes in Git repo, ArgoCD waits for updates

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 5	After Step 6	Final
Namespace 'argocd'	Not present	Created	Exists	Exists	Exists	Exists	Exists
ArgoCD app 'guestbook' status	Not present	Not present	Not present	Synced	OutOfSync	Synced	Synced
Cluster state	Old config	Old config	Old config	Old config	Old config	Updated to Git state	Updated to Git state

Key Moments - 3 Insights

Why does ArgoCD show 'OutOfSync' after I push changes to Git?

Because ArgoCD detects that the cluster state no longer matches the Git repo state (see execution_table step 5). It waits for a sync command or automatic sync to update the cluster.

What happens if I don't run 'argocd app sync' after pushing changes?

The cluster remains out of sync with Git repo (execution_table step 5). ArgoCD will not apply changes until sync is triggered manually or auto-sync is enabled.

Why do we create a separate namespace 'argocd' before installing ArgoCD?

Namespaces isolate resources in Kubernetes. Creating 'argocd' namespace (step 1) keeps ArgoCD components organized and separate from other apps.

Visual Quiz - 3 Questions

Look at the execution_table at step 5, what is the ArgoCD app 'guestbook' status?

A OutOfSync

B Unknown

C Synced

D Error

💡 Hint

Check the 'Result' column at step 5 in the execution_table.

At which step does the Kubernetes cluster update to match the Git repo?

A Step 5

B Step 6

C Step 3

D Step 7

💡 Hint

Look for the step where 'Cluster updated to match Git repo' appears in the execution_table.

If you skip creating the 'argocd' namespace, what will happen at step 2?

A ArgoCD installs in default namespace

B Namespace is created automatically

C Installation fails due to missing namespace

D ArgoCD installs but with errors

💡 Hint

Refer to variable_tracker for 'Namespace argocd' status after step 1 and step 2.

Concept Snapshot

GitOps with ArgoCD:
- ArgoCD watches Git repo for changes
- Changes trigger sync to Kubernetes cluster
- Cluster state matches Git repo state
- Use 'argocd app sync' to apply changes
- Namespace isolates ArgoCD components
- Status shows sync state (Synced/OutOfSync)

Full Transcript

GitOps with ArgoCD means using Git as the single source of truth for Kubernetes configurations. Developers push changes to a Git repository. ArgoCD continuously monitors this repo. When it detects changes, it marks the application as OutOfSync. Running 'argocd app sync' applies those changes to the Kubernetes cluster, updating it to match the Git state. The cluster then reports back as Synced. ArgoCD runs in its own namespace for organization. This process automates deployment and keeps cluster state consistent with Git.