RH134 - ch13s04

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Guided Exercise: Deploy Containers

In this exercise, you use container management tools to build an image, run a container, and query the running container environment.

Outcomes

Configure a container image registry and create a container from an existing image.
Create a container by using a container file.
Copy a script from a host machine into containers and run the script.
Delete containers and images.

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

This command prepares your environment and ensures that all required resources are available.

[student@workstation ~]$ lab start containers-deploy

Instructions

[student@workstation ~]$ ssh student@servera
...output omitted...
[student@servera ~]$

Install the container-tools meta-package.

[student@servera ~]$ sudo dnf install container-tools
[sudo] password for student: student
...output omitted...
Is this ok [y/N]: y
...output omitted...
Complete!

Configure the registry.lab.example.com classroom registry in your home directory. Log in to the container registry with admin as the user and redhat321 as the password.

Create the /home/student/.config/containers directory.

[student@servera ~]$ mkdir -p /home/student/.config/containers

Create the /home/student/.config/containers/registries.conf file with the following contents:

unqualified-search-registries = ['registry.lab.example.com']

[[registry]]
location = "registry.lab.example.com"
insecure = true
blocked = false

Verify that the classroom registry is added.

[student@servera ~]$ podman info
...output omitted...
registries:
  registry.lab.example.com:
    Blocked: false
    Insecure: true
    Location: registry.lab.example.com
    MirrorByDigestOnly: false
    Mirrors: null
    Prefix: registry.lab.example.com
  search:
  - registry.lab.example.com
...output omitted...

[student@servera ~]$ podman login registry.lab.example.com
Username: admin
Password: redhat321
Login Succeeded!

Run the python38 container in detached mode from an image with the python 3.8 package and based on the ubi8 image. The image is hosted on a remote registry.

Search for a python-38 container in the registry.lab.example.com registry.

[student@servera ~]$ podman search registry.lab.example.com/
NAME                                        DESCRIPTION
...output omitted...
registry.lab.example.com/ubi8/python-38
registry.lab.example.com/ubi8/httpd-24
registry.lab.example.com/rhel8/php-74

Inspect the image.

[student@servera ~]$ skopeo inspect \
docker://registry.lab.example.com/ubi8/python-38
...output omitted...
        "description": "Python 3.8 available as container is a base platform for building and running various Python 3.8 applications and frameworks.
...output omitted...

Pull the python-38 container image.

[student@servera ~]$ podman pull registry.lab.example.com/ubi8/python-38
Trying to pull registry.lab.example.com/ubi8/python-38:latest...
...output omitted...
671cc3cb42984e338733ebb5a9a68e69e267cb7f9cb802283d3bc066f6321617

Verify that the container is downloaded to the local image repository.

[student@servera ~]$ podman images
REPOSITORY                               TAG     IMAGE ID      CREATED     SIZE
registry.lab.example.com/ubi8/python-38  latest  671cc3cb4298  5 days ago  901 MB

Start the python38 container.

[student@servera ~]$ podman run -d --name python38 \
registry.lab.example.com/ubi8/python-38 sleep infinity
004756b52d3d3326545f5075594cffa858afd474b903288723a3aa299e72b1af

Verify that the container was created.

[student@servera ~]$ podman ps
CONTAINER ID  IMAGE                                             COMMAND         CREATED             STATUS                 PORTS       NAMES
004756b52d3d  registry.lab.example.com/ubi8/python-38:latest    sleep infinity  About a minute ago  Up About a minute ago              python38

Build a container image called python39:1.0 from a container file, and use the image to create a container called python39.

Examine the container file in the /home/student/python39 directory.

[student@servera ~]$ cat /home/student/python39/Containerfile
FROM registry.lab.example.com/ubi9-beta/ubi:latest
RUN echo -e '[rhel-9.0-for-x86_64-baseos-rpms]\nbaseurl = http://content.example.com/rhel9.0/x86_64/dvd/BaseOS\nenabled = true\ngpgcheck = false\nname = Red Hat Enterprise Linux 9.0 BaseOS (dvd)\n[rhel-9.0-for-x86_64-appstream-rpms]\nbaseurl = http://content.example.com/rhel9.0/x86_64/dvd/AppStream\nenabled = true\ngpgcheck = false\nname = Red Hat Enterprise Linux 9.0 Appstream (dvd)'>/etc/yum.repos.d/rhel_dvd.repo
RUN yum install --disablerepo=* --enablerepo=rhel-9.0-for-x86_64-baseos-rpms --enablerepo=rhel-9.0-for-x86_64-appstream-rpms -y python3

Create the container image from the container file.

[student@servera ~]$ podman build -t python39:1.0 /home/student/python39/.
STEP 1/4: FROM registry.lab.example.com/ubi9-beta/ubi:latest
...output omitted...
STEP 2/4: RUN echo -e '[rhel-9.0-for-x86_64-baseos-rpms] ...
...output omitted...
STEP 3/4: RUN yum install --disablerepo=* --enablerepo=rhel-9.0-for-x86_64-baseos-rpms --enablerepo=rhel-9.0-for-x86_64-appstream-rpms -y python3
...output omitted...
STEP 4/4: CMD ["/bin/bash", "-c", "sleep infinity"]
...output omitted...
Successfully tagged localhost/python39:1.0
80e68c195925beafe3b2ad7a54fe1e5673993db847276bc62d5f9d109e9eb499

Verify that the container image exists in the local image repository.

[student@servera ~]$ podman images
REPOSITORY                              TAG    IMAGE ID      CREATED        SIZE
localhost/python39                      1.0    80e68c195925  3 minutes ago  266 MB
registry.lab.example.com/ubi8/python-38 latest 671cc3cb4298  5 days ago     901 MB
registry.lab.example.com/ubi9-beta/ubi  latest fca12da1dc30  4 months ago   235 MB

Inspect the python39 container.

[student@servera ~]$ podman inspect localhost/python39:1.0
...output omitted...
            "comment": "FROM registry.lab.example.com/ubi9-beta/ubi:latest"
...output omitted...
            "created_by": "/bin/sh -c yum install --disablerepo=*
--enablerepo=rhel-9.0-for-x86_64-baseos-rpms --enablerepo=rhel-9.0-for-x86_64-appstream-rpms -y python3"
...output omitted...
            "created_by": "/bin/sh -c #(nop) CMD [\"/bin/bash\", \"-c\", \"sleep infinity\"]",
...output omitted...

Create the python39 container.

[student@servera ~]$ podman create --name python39 localhost/python39:1.0
3db4eabe9043224a7bdf195ab5fd810bf95db98dc29193392cef7b94489e1aae

Start the python39 container.

[student@servera ~]$ podman start python39
python39

Verify that the container is running.

[student@servera ~]$ podman ps
CONTAINER ID  IMAGE                                             COMMAND               CREATED             STATUS             PORTS       NAMES
004756b52d3d  registry.lab.example.com/ubi8/python-38:latest    sleep infinity        33 minutes ago      Up 33 minutes ago              python38
3db4eabe9043  localhost/python39:1.0                            /bin/bash -c slee...  About a minute ago  Up 42 seconds ago              python39

Copy the /home/student/script.py script into the /tmp directory of the running containers, and run the script on each container.

Copy the /home/student/script.py python script into the /tmp directory in both containers.

[student@servera ~]$ podman cp /home/student/script.py python39:/tmp/script.py
[student@servera ~]$ podman cp /home/student/script.py python38:/tmp/script.py

Run the Python script in both containers, and then run the Python script on the host.

[student@servera ~]$ podman exec -it python39 python3 /tmp/script.py
This script was not run on the correct version of Python
Expected version of Python is 3.8
Current version of python is 3.9
[student@servera ~]$ podman exec -it python38 python3 /tmp/script.py
This script was correctly run on Python 3.8
[student@servera ~]$ python3 /home/student/script.py
This script was not run on the correct version of Python
Expected version of Python is 3.8
Current version of python is 3.9

Delete containers and images. Return to workstation.

Stop both containers.

[student@servera ~]$ podman stop python39 python38
...output omitted...
python38
python39

Remove both containers.

[student@servera ~]$ podman rm python39 python38
3db4eabe9043224a7bdf195ab5fd810bf95db98dc29193392cef7b94489e1aae
004756b52d3d3326545f5075594cffa858afd474b903288723a3aa299e72b1af

Remove both container images.

[student@servera ~]$ podman rmi localhost/python39:1.0 \
registry.lab.example.com/ubi8/python-38:latest \
registry.lab.example.com/ubi9-beta/ubi
Untagged: localhost/python39:1.0
Untagged: registry.lab.example.com/ubi8/python-38:latest
Deleted: 80e68c195925beafe3b2ad7a54fe1e5673993db847276bc62d5f9d109e9eb499
Deleted: 219e43f6ff96fd11ea64f67cd6411c354dacbc5cbe296ff1fdbf5b717f01d89a
Deleted: 671cc3cb42984e338733ebb5a9a68e69e267cb7f9cb802283d3bc066f6321617

Return to workstation.

[student@servera ~]$ exit
logout
Connection to servera closed.

Finish

On the workstation machine, change to the student user home directory and 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 containers-deploy

This concludes the section.

Discuss Red Hat System Administration II

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Is It possible to reset root password when the system is on multi-user.target?

jennifer1987

27 lip 2023

Hi thereWell, i have a question, Is It possible to reset root password when the system is on multi-user.target? I was not be able to found a foro o some information related with this and another question that I have, If the grub menu dont show up, is it posible to reset the root password?

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Red Hat System Administration II (RH134)

Haley_Ruccio

21 lip 2023

Build the skills to perform the key tasks needed to become a full-time Linux administratorRed Hat System Administration II (RH134) is the second part of the RHCSA training track for IT professionals who have already attended Red Hat System Administration I. The course goes deeper into core Linux system administration skills in storage configuration and management, installation and deployment of Red Hat Enterprise Linux, management of security features such as SELinux, control of recurring system tasks, management of the boot process and troubleshooting, basic system tuning, and command-line automation and productivity. This course assumes that students have attended Red Hat System Administration I (RH124).Experienced Linux administrators who seek rapid preparation for the RHCSA certification should instead start with RHCSA Rapid Track (RH199).This course is based on Red Hat Enterprise Linux 9.0.Course summaryInstall Red Hat Enterprise Linux using scalable methodsAccess security files, file systems, and networksExecute shell scripting and automation techniquesManage storage devices, logical volumes, and file systemsManage security and system accessControl the boot process and system servicesRun containersAudience for this courseThis course is geared toward Windows system administrators, network administrators, and other system administrators who are interested in supplementing current skills or backstopping other team members, in addition to Linux system administrators who are responsible for these tasks:Configuring, installing, upgrading, and maintaining Linux systems using established standards and proceduresProviding operational supportManaging systems for monitoring system performance and availabilityWriting and deploying scripts for task automation and system administrationRecommended trainingSuccessful completion of Red Hat System Administration I (RH124) is recommended.Experienced Linux administrators seeking to accelerate their path toward becoming a Red Hat Certified System Administrator should start with the RHCSA Rapid Track course (RH199).Take our free assessment to gauge whether this offering is the best fit for your skills.Technology considerationsThere are no special technology requirements.This course is not designed for bring your own device (BYOD).Internet access is not required, but is recommended to allow students to research and access Red Hat online resources.

Welcome to the Red Hat System Administration II (RH134) group in the Red Hat Learning Community!

Deanna

18 lip 2023

We are excited to launch a space dedicated to the Red Hat Training course Red Hat System Administration II! 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 RH134.Read more about Red Hat System Administration II here.

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Revision: rh134-9.0-fa57cbe