# Guided Exercise: Externalize the Configuration of Applications Deploy a web server taking configuration files from a configuration map. **Outcomes** In this exercise, you deploy a web application to mount the missing files from a configuration map. * Create a web application deployment. * Expose the web application deployment to external access. * Create a configuration map from a file. * Mount the configuration map in the web application deployment. As the `student` user on the `workstation` machine, use the `lab` command to prepare your system for this exercise. This command ensures that the cluster is accessible. ```plaintext [student@workstation ~]$ lab start storage-configs ``` **Procedure 5.1. Instructions** 1. Create a web application deployment named `webconfig`. Use the [`registry.ocp4.example.com:8443/redhattraining/httpd-noimage:v1`](http://registry.ocp4.example.com:8443/redhattraining/httpd-noimage:v1) container image. 1. Log in to the OpenShift cluster as the `developer` user with the `developer` password. ```plaintext [student@workstation ~]$ oc login -u developer -p developer \ https://api.ocp4.example.com:6443 ..output omitted... ``` 2. Change to the `storage-configs` project. ```plaintext [student@workstation ~]$ oc project storage-configs Now using project "storage-configs" on server "https://api.ocp4.example.com:6443". ...output omitted... ``` 3. Create the `webconfig` deployment. Ignore the warning message. ```plaintext [student@workstation ~]$ oc create deployment webconfig \ --image registry.ocp4.example.com:8443/redhattraining/httpd-noimage:v1 Warning: would violate PodSecurity "restricted:v1.24": ...output omitted... deployment.apps/webconfig created ``` 4. Verify the deployment status. ```plaintext [student@workstation ~]$ oc get pods NAME READY STATUS ... webconfig-6cd5bddcf7-9ncdg 1/1 Running ... ``` 2. Expose the web application to external access. Use the following information to create a service and a route for the web application. | Service Field | Service Value | | --- | --- | | Service name | `webconfig-svc` | | Port number | `8080` | | Target port | `8080` | | Route Field | Route Value | | --- | --- | | Route name | `webconfig-rt` | | Service name | `webconfig-svc` | 1. Expose the `webconfig` deployment to create the `webconfig-svc` service. ```plaintext [student@workstation ~]$ oc expose deployment webconfig --name webconfig-svc \ --port 8080 --target-port 8080 service/webconfig-svc exposed ``` 2. Verify the status of the service. ```plaintext [student@workstation ~]$ oc get services NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) ... webconfig-svc ClusterIP 172.30.38.8 8080/TCP ... ``` ```plaintext [student@workstation ~]$ oc get pods -o wide NAME READY ... IP ... webconfig-6cd5bddcf7-9ncdg 1/1 ... 10.8.0.96 ... ``` 3. Expose the `webconfig-svc` service to create the `webconfig-rt` route. ```plaintext [student@workstation ~]$ oc expose service webconfig-svc --name webconfig-rt route.route.openshift.io/webconfig-rt exposed ``` ```plaintext [student@workstation ~]$ oc get routes NAME HOST/PORT ... SERVICES ... webconfig-rt webconfig-rt-storage-configs.apps.ocp4.example.com ... webconfig-svc ... ``` 4. Use a web browser to navigate to the [`http://webconfig-rt-storage-configs.apps.ocp4.example.com`](http://webconfig-rt-storage-configs.apps.ocp4.example.com) route, and then click the displayed link. An error message is displayed, because a file was not found on the server. 3. Use the missing file to create a configuration map. 1. Return to the terminal. Then, create a configuration map named `webfiles` by using the `redhatlogo.png` file in the `/home/student/DO180/labs/storage-configs` directory. ```plaintext [student@workstation ~]$ oc create configmap webfiles \ --from-file=/home/student/DO180/labs/storage-configs/redhatlogo.png configmap/webfiles created ``` 2. Verify the creation of the configuration map. ```plaintext [student@workstation ~]$ oc describe configmap webfiles Name: webfiles Namespace: storage-configs ...output omitted... BinaryData ==== redhatlogo.png: 3406 bytes ...output omitted.... ``` 4. Mount the `webfiles` configuration map as a volume in the `webconfig` deployment. 1. Mount the `webfiles` configuration map as a volume. Ignore the warning message. ```plaintext [student@workstation ~]$ oc set volume deployment/webconfig \ --add --type configmap --configmap-name webfiles \ --mount-path /var/www/html/redhatlogo.png Warning: would violate PodSecurity "restricted:v1.24": ...output omitted... deployment.apps/webconfig volume updated ``` 2. Verify the deployment status. Verify that a new pod was created. ```plaintext [student@workstation ~]$ oc status ...output omitted... http://webconfig-rt-storage-configs.apps.ocp4.example.com to pod port 8080 (svc/webconfig-svc) deployment/webconfig deploys registry.ocp4.example.com:8443/redhattraining/httpd-noimage:v1 deployment #2 running for 2 minutes - 1 pod deployment #1 deployed 17 minutes ago ...output omitted... ``` ```plaintext [student@workstation ~]$ oc get pods NAME READY STATUS ... webconfig-654bcf6cf-wcnnk 1/1 Running ... ...output omitted... ``` 3. Return to the web browser, and navigate to the [`webconfig-rt-storage-configs.apps.ocp4.example.com`](http://webconfig-rt-storage-configs.apps.ocp4.example.com) route. Then, click the link to open a list of files. Click **redhatlogo.png** to open the file.

The configuration map successfully added the missing image file to the web application. **Finish** On the `workstation` machine, use the `lab` command to complete this exercise. This step is important to ensure that resources from previous exercises do not impact upcoming exercises. ```plaintext [student@workstation ~]$ lab finish storage-configs ```