Managing the Kubernetes cluster is very simple if you use the right toolsets. Argo CD is one of the popular tools to manage the Kubernetes clusters in a declarative way. It’s a GitOps continuous delivery tool for Kubernetes. Argo CD helps to manage Application definitions, configurations, and environments in a declarative fashion and version controlled using git. Git repository going to remain a single source of truth for your cluster configuration and container deployments. This article will help to install and configure Argo CD. In the end, we will deploy the Nginx application using Argo CD for testing.
Argo CD is implemented as a Kubernetes controller which continuously monitors running applications in Kubernetes and compares the current, live state against the desired target state (as specified in the Git repo – YAML files). A deployed application whose live state deviates from the target state is considered out of sync. Argo CD reports and visualizes the differences while providing facilities to automatically or manually sync the live state back to the desired target state. Any modifications made to the desired target state in the Git repo can be automatically applied and reflected in the specified target environments.
RedHat will be started supporting Argo from Openshift 4.7 onwards.
Pre-requisites:
- Kubernetes Cluster
Deploying Argo CD
- Login to kubernetes cluster and ensure that you have access to admin access.
2. List the available namespaces in the Kubernetes cluster.
[root@kmaster ~]# kubectl get namespace NAME STATUS AGE default Active 25h kube-node-lease Active 25h kube-public Active 25h kube-system Active 25h [root@kmaster ~]#
3. Create a new namespace for Argo CD.
[root@kmaster ~]# kubectl create namespace argocd namespace/argocd created [root@kmaster ~]# kubectl get namespace argocd NAME STATUS AGE argocd Active 10s [root@kmaster ~]#
4. Deploy Argo CD using the “kubectl” command.
[root@kmaster ~]# kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml customresourcedefinition.apiextensions.k8s.io/applications.argoproj.io created customresourcedefinition.apiextensions.k8s.io/appprojects.argoproj.io created serviceaccount/argocd-application-controller created serviceaccount/argocd-dex-server created serviceaccount/argocd-redis created serviceaccount/argocd-server created role.rbac.authorization.k8s.io/argocd-application-controller created role.rbac.authorization.k8s.io/argocd-dex-server created role.rbac.authorization.k8s.io/argocd-redis created role.rbac.authorization.k8s.io/argocd-server created clusterrole.rbac.authorization.k8s.io/argocd-application-controller created clusterrole.rbac.authorization.k8s.io/argocd-server created rolebinding.rbac.authorization.k8s.io/argocd-application-controller created rolebinding.rbac.authorization.k8s.io/argocd-dex-server created rolebinding.rbac.authorization.k8s.io/argocd-redis created rolebinding.rbac.authorization.k8s.io/argocd-server created clusterrolebinding.rbac.authorization.k8s.io/argocd-application-controller created clusterrolebinding.rbac.authorization.k8s.io/argocd-server created configmap/argocd-cm created configmap/argocd-gpg-keys-cm created configmap/argocd-rbac-cm created configmap/argocd-ssh-known-hosts-cm created configmap/argocd-tls-certs-cm created secret/argocd-secret created service/argocd-dex-server created service/argocd-metrics created service/argocd-redis created service/argocd-repo-server created service/argocd-server created service/argocd-server-metrics created deployment.apps/argocd-dex-server created deployment.apps/argocd-redis created deployment.apps/argocd-repo-server created deployment.apps/argocd-server created statefulset.apps/argocd-application-controller created networkpolicy.networking.k8s.io/argocd-application-controller-network-policy created networkpolicy.networking.k8s.io/argocd-dex-server-network-policy created networkpolicy.networking.k8s.io/argocd-redis-network-policy created networkpolicy.networking.k8s.io/argocd-repo-server-network-policy created networkpolicy.networking.k8s.io/argocd-server-network-policy created [root@kmaster ~]#
5. List all the resources from “argocd” namespace.
[root@kmaster ~]# kubectl get all -n argocd NAME READY STATUS RESTARTS AGE pod/argocd-application-controller-0 1/1 Running 0 3h8m pod/argocd-dex-server-76ff776f97-6k9wr 1/1 Running 0 3h8m pod/argocd-redis-747b678f89-hjtqz 1/1 Running 0 3h8m pod/argocd-repo-server-6fc4456c89-5xxhg 1/1 Running 0 3h8m pod/argocd-server-7d57bc994b-xznhd 1/1 Running 0 3h8m NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/argocd-dex-server ClusterIP 10.116.0.253 5556/TCP,5557/TCP,5558/TCP 3h8m service/argocd-metrics ClusterIP 10.116.8.47 8082/TCP 3h8m service/argocd-redis ClusterIP 10.116.7.176 6379/TCP 3h8m service/argocd-repo-server ClusterIP 10.116.9.70 8081/TCP,8084/TCP 3h8m service/argocd-server ClusterIP 10.116.2.2 80/TCP,443/TCP 3h8m service/argocd-server-metrics ClusterIP 10.116.7.205 8083/TCP 3h8m NAME READY UP-TO-DATE AVAILABLE AGE deployment.apps/argocd-dex-server 1/1 1 1 3h8m deployment.apps/argocd-redis 1/1 1 1 3h8m deployment.apps/argocd-repo-server 1/1 1 1 3h8m deployment.apps/argocd-server 1/1 1 1 3h8m NAME DESIRED CURRENT READY AGE replicaset.apps/argocd-dex-server-76ff776f97 1 1 1 3h8m replicaset.apps/argocd-redis-747b678f89 1 1 1 3h8m replicaset.apps/argocd-repo-server-6fc4456c89 1 1 1 3h8m replicaset.apps/argocd-server-7d57bc994b 1 1 1 3h8m NAME READY AGE statefulset.apps/argocd-application-controller 1/1 3h8m [root@kmaster ~]#
6. By default, the Argo CD API server is not exposed with an external IP. To access the API server, Change the argocd-server service type to LoadBalancer. (On Cloud Native kubernetes deployments).
[root@kmaster ~]# kubectl patch svc argocd-server -n argocd -p '{"spec": {"type": "LoadBalancer"}}'
service/argocd-server patched
[root@kmaster ~]#
[root@kmaster ~]# kubectl get svc -n argocd
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
argocd-dex-server ClusterIP 10.116.0.253 5556/TCP,5557/TCP,5558/TCP 3h12m
argocd-metrics ClusterIP 10.116.8.47 8082/TCP 3h12m
argocd-redis ClusterIP 10.116.7.176 6379/TCP 3h12m
argocd-repo-server ClusterIP 10.116.9.70 8081/TCP,8084/TCP 3h12m
argocd-server LoadBalancer 10.116.2.2 80:32334/TCP,443:31609/TCP 3h12m
argocd-server-metrics ClusterIP 10.116.7.205 8083/TCP 3h12m
[root@kmaster ~]# kubectl get svc -n argocd
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
argocd-dex-server ClusterIP 10.116.0.253 5556/TCP,5557/TCP,5558/TCP 3h13m
argocd-metrics ClusterIP 10.116.8.47 8082/TCP 3h13m
argocd-redis ClusterIP 10.116.7.176 6379/TCP 3h13m
argocd-repo-server ClusterIP 10.116.9.70 8081/TCP,8084/TCP 3h13m
argocd-server LoadBalancer 10.116.2.2 34.102.80.202 80:32334/TCP,443:31609/TCP 3h13m
argocd-server-metrics ClusterIP 10.116.7.205 8083/TCP 3h13m
[root@kmaster ~]#
Here is the external IP to access the Argo CD GUI.
[root@kmaster ~]# kubectl get svc -n argocd |grep LoadBalancer argocd-server LoadBalancer 10.116.2.2 34.102.80.202 80:32334/TCP,443:31609/TCP 3h18m [root@kmaster ~]#
7. The initial password for the ArgoCD admin account is auto-generated. It’s stored as clear text in the field password in a secret named argocd-initial-admin-secret in your Argo CD installation namespace (argocd). You can simply retrieve this password using kubectl:
[root@kmaster ~]# kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d
onwC......darPJBKp
[root@kmaster ~]#
8. Login to GUI with username “admin” and retrieved password using kubectl.
9. Here is the argo CD home page.
We have successfully deployed Argo CD in kubernetes cluster. Click on “New App” to start deploying new applications.
Deploy new application using Argo CD
- Once you have clicked on “New App” the following window will be poping up to get the repo and project details. Click on “EDIT AS YAML” to populate values using YAML.
2. Copy & paste the following YAML codes and save.
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
name: guestbook
spec:
destination:
name: ''
namespace: guestbook
server: 'https://kubernetes.default.svc'
source:
path: helm-guestbook
repoURL: 'https://github.com/argoproj/argocd-example-apps.git'
targetRevision: HEAD
project: default
helm:
parameters:
- name: service.port
value: '80'
syncPolicy:
syncOptions:
- CreateNamespace=true
3. Click on create to deploy new app using argo CD.
4. Since we haven’t enabled auto sync, our newly created app is showing “out of sync”. Click on “SYNC” .
5. Click on “SYNCHRONIZE” to deploy the application in to kubernetes cluster.
6. Once the application is synced with cluster, it will create a beautifull application tree. Click the application to view the tree.
7. Here is the application tree.
8. Here is the new deployment resources list in kubernetes.
[root@kmaster ~]# kubectl get all -n guestbook NAME READY STATUS RESTARTS AGE pod/guestbook-helm-guestbook-7ff45f5456-vhq56 1/1 Running 0 34m NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/guestbook-helm-guestbook ClusterIP 10.116.1.209 80/TCP 34m NAME READY UP-TO-DATE AVAILABLE AGE deployment.apps/guestbook-helm-guestbook 1/1 1 1 34m NAME DESIRED CURRENT READY AGE replicaset.apps/guestbook-helm-guestbook-7ff45f5456 1 1 1 34m [root@kmaster ~]#
We have successfully deployed argo CD and deployed new application using argo CD. Hope this article is informative to you.