---
title: "Updating an application"
sidebar_position: 40
---

Now we can use Argo CD and Kustomize to deploy patches to our application manifests using GitOps

For example, lets increase the number of `replicas` for `ui` deployment to `3`

<!--
```kustomization
modules/automation/gitops/argocd/update-application/deployment-patch.yaml
Deployment/ui
```

Copy patch file to the Git repository directory:

```bash
$ cp /workspace/modules/automation/gitops/argocd/update-application/deployment-patch.yaml ~/environment/argocd/apps/deployment-patch.yaml
```

You can review planned changes in the file `apps/deployment-patch.yaml`

To apply the patch you can edit the file `apps/kustomization.yaml` like in the example below:

```file
manifests/modules/automation/gitops/argocd/update-application/kustomization.yaml.example
```

Copy edited file `kustomization.yaml` to the Git repository directory:

```bash
$ cp /workspace/modules/automation/gitops/argocd/update-application/kustomization.yaml.example ~/environment/argocd/apps/kustomization.yaml
```
-->

You can execute commands to add necessary changes to the file `apps/deployment.yaml`:

```bash
$ yq -i '.spec.replicas = 3' ~/environment/argocd/apps/deployment.yaml
```

Push changes to the Git repository

```bash
$ git -C ~/environment/argocd add .
$ git -C ~/environment/argocd commit -am "Update UI service replicas"
$ git -C ~/environment/argocd push
```

Click `Refresh` and `Sync` in ArgoCD UI or use `argocd` CLI to `Sync` the application:

```bash
$ argocd app sync apps
```

We should have now 3 pods in `ui` deployment

![argocd-update-application](assets/argocd-update-application.png)

To verify, run the following commands:

```bash hook=update
$ kubectl get deployment -n ui ui
NAME   READY   UP-TO-DATE   AVAILABLE   AGE
ui     3/3     3            3           3m33s
$ kubectl get pod -n ui
NAME                 READY   STATUS    RESTARTS   AGE
ui-6d5bb7b95-hzmgp   1/1     Running   0          61s
ui-6d5bb7b95-j28ww   1/1     Running   0          61s
ui-6d5bb7b95-rjfxd   1/1     Running   0          3m34s
```