DO288 - ch06s07

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Lab: Deploying Multi-container Applications

Create a Helm chart to deploy a multi-container application.

Customize a multi-container application for different environments with Kustomize.

Outcomes

Create a Helm chart from manifest files.
Use Kustomize for local updates on a Helm chart.

As the student user on the workstation machine, use the lab command to prepare your environment for this exercise, and to ensure that all required resources are available.

[student@workstation ~]$ lab start multicontainer-review

Instructions

The lab script copies the Helm chart files for the famous-quotes application, which uses a Redis data store.

In this lab, you are asked to create a Helm chart by using the files that the exercise provides and later using Kustomize to apply customization to the rendered chart. You are expected to work with Helm locally, without the need for a Helm repository.

[student@workstation ~]$ oc login -u developer -p developer \
https://api.ocp4.example.com:6443
Login successful.
...output omitted...

Ensure that you use the multicontainer-review project.

[student@workstation ~]$ oc project multicontainer-review
Already on project "multicontainer-review" on server "https://api.ocp4.example.com:6443".

Create a Helm chart from the files in the ~/DO288/labs/multicontainer-review/famous-quotes directory.

In a terminal window, change to the famous-quotes application directory.

[student@workstation ~]$ cd ~/DO288/labs/multicontainer-review/famous-quotes

Move the files in the famous-quotes directory according to the Helm chart layout.

First, move the chart template files to the templates directory.

[student@workstation famous-quotes]$ mv \
 configmap.yaml \
 deployment.yaml \
 route.yaml \
 service.yaml \
templates/

Then, move the pre-downloaded chart dependency to the charts directory.

[student@workstation famous-quotes]$ mv redis-persistent-0.0.1.tgz charts/

When you run the tree command you must get the following output:

[student@workstation famous-quotes]$ tree ./
./
├── charts
│   └── redis-persistent-0.0.1.tgz
├── Chart.yaml
├── templates
│   ├── configmap.yaml
│   ├── deployment.yaml
│   ├── route.yaml
│   └── service.yaml
└── values.yaml

3 directories, 7 files

Verify that the famous-quotes templates and the Redis chart are in the correct location.

[student@workstation famous-quotes]$ helm template ./ | grep  "# Source:" | sort
# Source: famous-quotes/charts/redis/templates/deploymentconfig.yaml
# Source: famous-quotes/charts/redis/templates/persistentvolumeclaim.yaml
# Source: famous-quotes/charts/redis/templates/secret.yaml
# Source: famous-quotes/charts/redis/templates/service.yaml
# Source: famous-quotes/charts/redis/templates/tests/test-redis-connection.yaml
# Source: famous-quotes/templates/configmap.yaml
# Source: famous-quotes/templates/deployment.yaml
# Source: famous-quotes/templates/route.yaml
# Source: famous-quotes/templates/service.yaml

Update the Helm templates to use the values in the quotes key of the values.yaml file.

Add the following features to the chart:

Parameterize the famous-quotes image name.
Use the quotes.import.enabled value to optionally add the volume and the import configuration to the famous-quotes deployment.
Use the quotes.import.enabled value to optionally create the configuration map that contains the import data.

Edit the templates/deployment.yaml template to use the quotes.image value.

...output omitted...
    spec:
      containers:
      - name: famous-quotes
        image: {{ .Values.quotes.image }}
...output omitted...

Edit the templates/deployment.yaml template to make the data import configuration and volume optional.

...output omitted...
        - name: DATASTORE_PASS
          valueFrom:
            secretKeyRef:
              key: database-password
              name: {{ .Values.redis.database_service_name }}
      {{- if .Values.quotes.import.enabled }}
        - name: QUOTES_IMPORT_PATH
          value: /tmp/quotes/import_quotes.csv
        volumeMounts:
          - name: import-volume
            mountPath: /tmp/quotes
      volumes:
        - name: import-volume
          configMap:
            name: quotes-import-data
      {{- end }}

Verify that the updates to the templates/deployment.yaml file render correctly.

Verify that the image value displays and that there is no data import configuration.

[student@workstation famous-quotes]$ helm template ./ \
--set quotes.import.enabled=false \
| grep -A 28 "famous-quotes/templates/deployment.yaml"
# Source: famous-quotes/templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: famous-quotes
...output omitted...
      containers:
      - name: famous-quotes
        image: registry.ocp4.example.com:8443/redhattraining/ocpdev-redis-quotes:4.12
        imagePullPolicy: Always
        env:
        - name: DATASTORE_HOST
          value: quotes-store
        - name: DATASTORE_PASS
          valueFrom:
            secretKeyRef:
              key: database-password
              name: quotes-store
---
# Source: famous-quotes/charts/redis/templates/deploymentconfig.yaml

Edit the templates/configmap.yaml template to use the quotes.import.enabled value to conditionally create the quotes-import-data configuration map.

{{- if .Values.quotes.import.enabled }}
apiVersion: v1
kind: ConfigMap
metadata:
  name: quotes-import-data
data:
  import_quotes.csv: |-
    id|quote|author
...output omitted...
    8|Those who can imagine anything, can create the impossible.|Alan Turing
{{- end }}

Run the helm template with the quotes.import.enabled parameter set to false to verify that the configuration map does not render.

[student@workstation famous-quotes]$ helm template ./ \
--set quotes.import.enabled=false \
| grep "# Source\|templates/configmap.yaml"
# Source: famous-quotes/charts/redis/templates/secret.yaml
# Source: famous-quotes/charts/redis/templates/persistentvolumeclaim.yaml
# Source: famous-quotes/charts/redis/templates/service.yaml
# Source: famous-quotes/templates/service.yaml
# Source: famous-quotes/templates/deployment.yaml
# Source: famous-quotes/charts/redis/templates/deploymentconfig.yaml
# Source: famous-quotes/templates/route.yaml
# Source: famous-quotes/charts/redis/templates/tests/test-redis-connection.yaml

Optionally, run the previous command with the quotes.import.enabled=true parameter to verify that the configuration map shows in the output.

Use the output of the local famous-quotes chart render to create the ~/DO288/labs/multicontainer-review/kustomized-quotes/base/app.yaml file.
Use the --skip-tests option for the helm template command to avoid rendering the chart in the app.yaml file.
[student@workstation famous-quotes]$ helm template \ --skip-tests ./ > ../kustomized-quotes/base/app.yaml

Add the required files to the kustomized-quotes directory to have working staging and production customizations for the famous-quotes application.

The ~/DO288/labs/multicontainer-review/kustomized-quotes directory contains the base and overlays directory convention, but is missing some files that Kustomize requires.

kustomized-quotes
├── base
│   └── app.yaml # Generated in the Helm part of the exercise
└── overlays
    ├── production
    │   └── app_dimensioning.yaml
    └── staging
        └── app_dimensioning.yaml

Change to the kustomized-quotes directory.

[student@workstation famous-quotes]$ cd \
~/DO288/labs/multicontainer-review/kustomized-quotes

Create the base/kustomization.yaml file with the following content:
```
resources:
- app.yaml
```

Verify that you can run oc kustomize with the base directory.

[student@workstation kustomized-quotes]$ oc kustomize base/
apiVersion: v1
data:
  import_quotes.csv: |-
...output omitted...

Create the overlays/staging/kustomization.yaml file with the following content:
```
bases:
- ../../base
patches:
- staging_dimensioning.yaml
```

Verify that you can run oc kustomize with the overlays/staging directory.

[student@workstation kustomized-quotes]$ oc kustomize overlays/staging
apiVersion: v1
data:
  import_quotes.csv: |-
    id|quote|author
...output omitted...

Create the overlays/production/kustomization.yaml file with the following content:
```
bases:
- ../../base
patches:
- prod_dimensioning.yaml
```

Verify that you can run oc kustomize with the overlays/production directory.

[student@workstation kustomized-quotes]$ oc kustomize overlays/production
apiVersion: v1
data:
  import_quotes.csv: |-
    id|quote|author
...output omitted...

Verify the directory structure.

[student@workstation kustomized-quotes]$ tree ./
./
├── base
│   ├── app.yaml
│   └── kustomization.yaml
└── overlays
    ├── production
    │   ├── kustomization.yaml
    │   └── prod_dimensioning.yaml
    └── staging
        ├── kustomization.yaml
        └── staging_dimensioning.yaml

4 directories, 6 files

Deploy the staging version of the application.

Run the following command to deploy the staging version of the application.
```
[student@workstation kustomized-quotes]$ oc apply -k overlays/staging
```

Verify that the application and the Redis pods are running.

[student@workstation kustomized-quotes]$ oc get po
NAME                            READY   STATUS      RESTARTS      AGE
famous-quotes-d64ffc75f-kwzgw   1/1     Running     2 (36s ago)   59s
quotes-store-1-deploy           0/1     Completed   0             58s
quotes-store-1-sjv7p            1/1     Running     0             55s

Use the curl command to test that the application works.

[student@workstation kustomized-quotes]$ curl \
famous-quotes-multicontainer-review.apps.ocp4.example.com/quotes/5
{
  "quote" : "Imagination is more important than knowledge.",
  "author" : "Albert Einstein",
  "_links" : {
    "self" : {
      "href" : "http://famous-quotes-multicontainer-review.apps.ocp4.example.com/quotes/5"
    },
    "quote" : {
      "href" : "http://famous-quotes-multicontainer-review.apps.ocp4.example.com/quotes/5"
    }
  }
}

Evaluation

As the student user on the workstation machine, use the lab command to grade your work. Correct any reported failures and rerun the command until successful.

[student@workstation ~]$ lab grade multicontainer-review

Finish

As the student user 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.

[student@workstation ~]$ lab finish multicontainer-review

Discuss Red Hat OpenShift Developer II: Building and Deploying Cloud-native Applications

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Red Hat OpenShift Developer II: Building Kubernetes Applications (DO288)

Haley_Ruccio

31 lip 2023

Design, build, and deploy containerized applications on Red Hat OpenShiftRed Hat OpenShift Developer II: Building Kubernetes Applications (DO288) teaches you how to design, build, and deploy containerized software applications on an OpenShift clusterWhether you are migrating existing applications or writing container-native applications, you will learn how to boost developer productivity powered by Red Hat® OpenShift Container Platform, a containerized application platform that allows enterprises to manage container deployments and scale their applications using Kubernetes.This course is based on Red Hat OpenShift Container Platform 4.10.Course content summaryDesign containerized applications for OpenShift.Manage and trigger application builds using Source-to-Image (S2I).Customize an existing source-to-image base image.Deploy multi-container applications using Helm Charts.Create health checks to monitor and improve application reliability.Create and deploy cloud-native applications on OpenShift.Audience for this courseEnterprise application developersDevOps site reliability engineersRecommended for this courseTake our free assessment to gauge whether this offering is the best fit for your skills.View the Red Hat OpenShift skill paths.Complete Red Hat OpenShift I: Containers & Kubernetes (DO180), or have equivalent knowledgeBeing a Red Hat Certified System Administrator or having earned a higher certification is helpful for navigation and usage of the command line, but is not requiredTechnology considerationsThis course uses a lab environment provisioned in the Red Hat Online Learning (ROL) cloud.Internet access is required to run the exercises and labs.

Welcome to the Red Hat OpenShift Developer II (DO288) group in the Red Hat Learning Community!

Deanna

31 lip 2023

We are excited to launch a space dedicated to the Red Hat Training course DO288! To gain the most value from this group - click the "Join Group" button in the upper right hand corner.We encourage group members to collaborate in this group to discuss topics, ask questions, share best practices and tips, provide course feedback, and share their accomplishments as it relates to DO288.Read more about Red Hat OpenShift Developer II: Building Kubernetes Applications here.

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Revision: do288-4.12-0d49506