DO188 - ch07s05

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Lab: Multi-container Applications with Compose

Create a compose file to deploy your application in a testing environment. The application uses three components: a UI, a back end, and an external service that the back end uses. Because the development team does not own the external service, they decided to use a mock server called Wiremock to mock the external service interactions with the back end.

Outcomes

You should be able to:

Create a multi-container compose file with the following features:
- Bind mounts
- Environment variables
- Networks
- Published ports
Reload the compose file after modifying it.

As the student user on the workstation machine, use the lab command to prepare your system for this exercise.

[student@workstation ~]$ lab start compose-lab

The start function copies a file called compose.yaml that you must complete throughout this exercise. It also copies the configuration for wiremock to mock the quotes-provider service.

The lab script continuously evaluates the objectives of this lab. Keep the script running in a terminal window and complete the objectives of this lab from a new terminal window.

Instructions

Change into the ~/DO188/labs/compose-lab directory. This directory contains the compose file called compose.yaml, which you must complete. Then, start the containers in the background.

Container Name	Image
`quotes-provider`	`registry.ocp4.example.com:8443/redhattraining/wiremock`
`quotes-api`	`registry.ocp4.example.com:8443/redhattraining/podman-quotesapi-compose`
`quotes-ui`	`registry.ocp4.example.com:8443/redhattraining/podman-quotes-ui`

Note

The WireMock container image provides the ability to create a fake API service. This exercise uses this image to run the quotes-provider API. In a real-world scenario, your API image is built from your application source code.

Change into the ~/DO188/labs/compose-lab directory.

[student@workstation compose-lab]$ cd ~/DO188/labs/compose-lab
no output expected

Update the compose.yaml file to look like the following code block:

services:
  wiremock:
    container_name: "quotes-provider"
    image: "registry.ocp4.example.com:8443/redhattraining/wiremock"
  quotes-api:
    container_name: "quotes-api"
    image: "registry.ocp4.example.com:8443/redhattraining/podman-quotesapi-compose"
  quotes-ui:
    container_name: "quotes-ui"
    image: "registry.ocp4.example.com:8443/redhattraining/podman-quotes-ui"

From the directory that contains the compose.yaml file, run podman-compose up to create the containers. Use the -d option to run the containers in the background.
```
[student@workstation compose-lab]$ podman-compose up -d
['podman', '--version', '']
using podman version: ...
** excluding:  set()
...output omitted...
```

Configure the quotes-provider mock service by providing the Wiremock mappings and responses in the ~/DO188/labs/compose-lab/wiremock/stubs directory.

Wiremock expects two directories to configure the mock server:

mappings: contains files that define the HTTP endpoints.
__files: contains files with fixed responses.

To provide the Wiremock configuration, mount the ~/DO188/labs/compose-lab/wiremock/stubs directory as the /home/wiremock directory in the container.

To apply the changes, delete and restart the containers by using the podman-compose command.

Use a bind mount to map ~/DO188/labs/compose-lab/wiremock/stubs to the /home/wiremock directory. Provide the Z option to add the correct SELinux permissions.

services:
  wiremock:
    container_name: "quotes-provider"
    image: "registry.ocp4.example.com:8443/redhattraining/wiremock"
    volumes:
      - ~/DO188/labs/compose-lab/wiremock/stubs:/home/wiremock:Z
  quotes-api:
    container_name: "quotes-api"
    image: "registry.ocp4.example.com:8443/redhattraining/podman-quotesapi-compose"
  quotes-ui:
    container_name: "quotes-ui"
    image: "registry.ocp4.example.com:8443/redhattraining/podman-quotes-ui"

Apply the changes by running the podman-compose down command followed by podman-compose up -d.

Run podman-compose down to stop and remove the containers in the compose.yaml file.

[student@workstation compose-lab]$ podman-compose down
['podman', '--version', '']
using podman version: ...
** excluding:  set()
podman stop -t 10 quotes-ui
quotes-ui
exit code: 0
podman stop -t 10 quotes-api
quotes-api
exit code: 0
podman stop -t 10 quotes-provider
quotes-provider
exit code: 0
podman rm quotes-ui
ff3d...093e
exit code: 0
podman rm quotes-api
2a5d...5be3
exit code: 0
podman rm quotes-provider
48c9...c2f8
exit code: 0

Run podman-compose up to re-create the containers with the new changes.

[student@workstation compose-lab]$ podman-compose up -d
['podman', '--version', '']
using podman version: ...
** excluding:  set()
...output omitted...

Expose the quotes-api service to the host machine on port 8080. The quotes-api service listens on port 8080 in the container.

To apply the changes, delete and restart the containers by using the podman-compose command.

Use the ports property to expose the port 8080 in the container to port 8080 on the host.

services:
  wiremock:
    container_name: "quotes-provider"
    image: "registry.ocp4.example.com:8443/redhattraining/wiremock"
    volumes:
      - ~/DO188/labs/compose-lab/wiremock/stubs:/home/wiremock:Z
  quotes-api:
    container_name: "quotes-api"
    image: "registry.ocp4.example.com:8443/redhattraining/podman-quotesapi-compose"
    ports:
      - "8080:8080"
  quotes-ui:
    container_name: "quotes-ui"
    image: "registry.ocp4.example.com:8443/redhattraining/podman-quotes-ui"

Apply the changes by running the podman-compose down command followed by podman-compose up -d.
Run podman-compose down to stop and remove the containers in the compose.yaml file.
```
[student@workstation compose-lab]$ podman-compose down
...output omitted...
```
Run podman-compose up to re-create the containers with the new changes.
```
[student@workstation compose-lab]$ podman-compose up -d
...output omitted...
```

Isolate together the quotes-provider and quotes-api services by creating a Podman network called lab-net in the compose.yaml file.

To apply the changes, delete and restart the containers by using the podman-compose command.

Use the networks top-level property to create the lab-net network from the compose.yaml file. Then use the networks property under the wiremock and quotes-api services to connect both containers to the lab-net network.

services:
  wiremock:
    container_name: "quotes-provider"
    image: "registry.ocp4.example.com:8443/redhattraining/wiremock"
    volumes:
      - ~/DO188/labs/compose-lab/wiremock/stubs:/home/wiremock:Z
    networks:
      - lab-net
  quotes-api:
    container_name: "quotes-api"
    image: "registry.ocp4.example.com:8443/redhattraining/podman-quotesapi-compose"
    ports:
      - "8080:8080"
    networks:
      - lab-net
  quotes-ui:
    container_name: "quotes-ui"
    image: "registry.ocp4.example.com:8443/redhattraining/podman-quotes-ui"

networks:
  lab-net: {}

Apply the changes by running the podman-compose down command followed by the podman-compose up -d command.
Run the podman-compose down command to stop and remove the containers in the compose.yaml file.
```
[student@workstation compose-lab]$ podman-compose down
...output omitted...
```
Run the podman-compose up command to re-create the containers with the new changes.
```
[student@workstation compose-lab]$ podman-compose up -d
...output omitted...
```

The quotes-api and quotes-provider services share a network, but the quotes-api service is missing the hostname configuration of the provider endpoint. Set the QUOTES_SERVICE environment variable to configure the quotes-provider URL. Use the default name resolution, the quotes-provider configuration, the http protocol, and the port 8080 to configure this value.
To apply the changes, delete and restart the containers by using the podman-compose command.
Add the QUOTES_SERVICE="http://quotes-provider:8080" environment variable to the compose.yaml file.
services: wiremock: container_name: "quotes-provider" image: "registry.ocp4.example.com:8443/redhattraining/wiremock" volumes: - ~/DO188/labs/compose-lab/wiremock/stubs:/home/wiremock:Z networks: - lab-net quotes-api: container_name: "quotes-api" image: "registry.ocp4.example.com:8443/redhattraining/podman-quotesapi-compose" ports: - "8080:8080" networks: - lab-net environment: QUOTES_SERVICE: "http://quotes-provider:8080" quotes-ui: container_name: "quotes-ui" image: "registry.ocp4.example.com:8443/redhattraining/podman-quotes-ui" networks: lab-net: {}
Apply the changes by running the podman-compose down command followed by the podman-compose up -d command.
Run the podman-compose down command to stop and remove the containers in the compose.yaml file.
[student@workstation compose-lab]$ podman-compose down ...output omitted...
Run the podman-compose up command to re-create the containers with the new changes.
[student@workstation compose-lab]$ podman-compose up -d ...output omitted...

Expose the quotes-ui service on port 3000 so that the host can access the application on http://localhost:3000. The quotes-ui is listening on port 8080 in the UI container.

To apply the changes, delete and restart the containers by using the podman-compose command.

Use the previous URL to visit the quotes application by using a web browser.

Use the ports property in the quotes-ui service to expose the port 8080 in the container to port 3000 on the host.

services:
  wiremock:
    container_name: "quotes-provider"
    image: "registry.ocp4.example.com:8443/redhattraining/wiremock"
    volumes:
      - ~/DO188/labs/compose-lab/wiremock/stubs:/home/wiremock:Z
    networks:
      - lab-net
  quotes-api:
    container_name: "quotes-api"
    image: "registry.ocp4.example.com:8443/redhattraining/podman-quotesapi-compose"
    ports:
      - "8080:8080"
    networks:
      - lab-net
    environment:
      QUOTES_SERVICE: "http://quotes-provider:8080"
  quotes-ui:
    container_name: "quotes-ui"
    image: "registry.ocp4.example.com:8443/redhattraining/podman-quotes-ui"
    ports:
      - "3000:8080"

networks:
  lab-net: {}

Apply the changes by running the podman-compose down command followed by the podman-compose up -d command.
Run the podman-compose down command to stop and remove the containers in the compose.yaml file.
```
[student@workstation compose-lab]$ podman-compose down
...output omitted...
```
Run the podman-compose up command to re-create the containers with the new changes.
```
[student@workstation compose-lab]$ podman-compose up -d
...output omitted...
```
Navigate to http://localhost:3000 to verify that the quotes application shows famous quotes in the browser.

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.

Press y when the lab start command prompts you to execute the finish function. Alternatively, execute the following command:

[student@workstation ~]$ lab finish compose-lab

Discuss Red Hat OpenShift Development I: Introduction to Containers with Podman

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Red Hat OpenShift Development I: Introduction to Containers with Podman (DO188)

Haley_Ruccio

26 lip 2023

A developer introduction to building and managing containers with Podman for deploying applications on Red Hat OpenShift Container Platform.Red Hat OpenShift Development I: Introduction to Containers with Podman (DO188) introduces students to building, running, and managing containers with Podman and Red Hat OpenShift. This course helps students build the core skills for developing containerized applications through hands-on experience. These skills can be applied using all versions of OpenShift, including Red Hat OpenShift on AWS (ROSA), Azure Red Hat OpenShift, and OpenShift Container Platform.This course is based on Red Hat® Enterprise Linux® 8, Podman 4.2 and Red Hat OpenShift® 4.12.Course content summaryIntroduction to containersRun containers with Podman CLI and Podman DesktopBuild custom container imagesManage container imagesRemote debugging with containersBasic container networkingPersist data with containersRun multi-container applicationsTroubleshoot Container DeploymentsOrchestrate containers with OpenShift and KubernetesAudience for this courseDevelopers and Site Reliability Engineers that are new to container technology.System administrators and platform operators who are interested in managing OpenShift clusters and containerized applications should enroll in Red Hat OpenShift Administration I: Containers & Kubernetes (DO180).Prerequisites for this courseTake our free assessment to gauge whether this offering is the best fit for your skills.Some experience with web application architectures and their corresponding technologies.Experience in the use of a Linux terminal session, issuing operating system commands, and familiarity with shell scripting is recommended.Technology considerationsRequires internet connection.

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Welcome to the Red Hat OpenShift Development: Intro to containers with Podman (DO188) group!

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18 lip 2023

We are excited to launch a space dedicated to the Red Hat Training courseRed Hat OpenShift Development I: Introduction to Containers with Podman! 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 DO188.Read more about Red Hat OpenShift Development: Intro to containers with Podman here.

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Revision: do188-4.14-8c43a16