This course covers a range of techniques to help you run your own containerized applications using Red Hat. Throughout this course, you will follow along with guided presentations from the Red Hat platform to get a first-hand understanding of how to run containers and manage your workflows using Red Hat.
- Learn the basics of setting up web servers and containers
- Understand how to find and manage containers
- Understand how to perform advanced container management
- Learn how to attach persistent storage to a container
- Learn how to manage containers as services
This course is ideal for anyone who wants to learn how to run containers with Red Hat.
To get the most out of this course, you should have a basic understanding of Red Hat and of how containers work.
Right now we are going to have a look at the guided exercise, of course we are focusing on Finding and Managing Container Images.
So, from a terminal from the workstation virtual machine, we are going to be running the command lab containers-managing start and as you can see we have success which means we can proceed.
So, first up what we are going to do is make an ssh connection to our container host and that is servera and from there we are going to have a look at the registries. Now what I really like about using podman is that you don't need root to run containers, you don't need root to download images, you don't need to be root to set up your registry. So, what has happened over here is that in the student users home directory we have the directory .config sub-directory containers and we have that registries.conf file. So, over here guys you can see the registries that we are evaluating.
Having said that what we are now going to do is use the command podman search and we are going to evaluate the registry registry.lab.example.com and we are searching for images that have the string ubi in them. So, ubi or the universal base image, you could see that we have two results right now. Here we have ubi version 7 which looks and feels like Red Hat Enterprise Linux 7. Similarly, we have ubi8 which looks and feels like rhel8. So, what we're going to do right now is use the podman login command. So, we are going to log in to registry.lab.example.com. Yes I know, bad practice to have the username and the password on the command line but this is a training environment and I also want you guys to see that I am logged in as the user admin with the password redhat321.
So, moving on to step five right now we are told to make use of the skopeo command. So, we are doing a skopeo inspect and we are going to evaluate the image located at registry.lab.example.com/ rhel8/httpd-24 and guys I am showing you the first 19 lines over here. So, look at that metadata, see container images are not all about just the files and the directories that are going to be deployed into your container, we also have this precious metadata as well.
So, next at step number 6 what we are doing is that we are going to download the container image.
So you could see the use of the podman pull command. So, we are downloading the blobs right now, which means that afterwards when you run the command podman images you should see that you have an image that has been downloaded locally. So, this image right now is on servera which means that we can quickly and easily start a container from this image. So, looking at step 8 what we are going to do right now is use podman inspect.
So, we are going to inspect the image that we have just downloaded that's registry.lab.example.com and I am just showing you the first 18 lines but you could see very importantly over here, let me highlight it for you. It gives me information, more information about the about the image. So, this image invariably uses some ports, the ports that we are using include port 8080 as well as 8443 and those aren't unprivileged ports. You don't need to be rude to run containers.
So, next up guys all we are going to do right now is delete that image. So, using the command podman rmi, we are deleting the image which means that when you run the command podman images thereafter you won't have any images downloaded to your container host.
When you've had your fun, feel free to log out or simply hit exit or what I do, I use ctrl d because I am way too lazy to type exit or logout but guys what you could do to wrap up is run the command lab containers-managing finish from the workstation machine and with that it does bring this guided exercise to an end, I will see you in the next video.
Jeremy is a Content Lead Architect and DevOps SME here at Cloud Academy where he specializes in developing DevOps technical training documentation.
He has a strong background in software engineering, and has been coding with various languages, frameworks, and systems for the past 25+ years. In recent times, Jeremy has been focused on DevOps, Cloud (AWS, Azure, GCP), Security, Kubernetes, and Machine Learning.
Jeremy holds professional certifications for AWS, Azure, GCP, Terraform, Kubernetes (CKA, CKAD, CKS).