Description
CRI-O is an implementation of the Kubernetes CRI (Container Runtime Interface) to enable using OCI (Open Container Initiative) compatible runtimes. It is a lightweight alternative to using Docker as the runtime for kubernetes. It allows Kubernetes to use any OCI-compliant runtime as the container runtime for running pods. Today it supports runc and Clear Containers as the container runtimes but any OCI-conformant runtime can be plugged in principle.CRI-O supports OCI container images and can pull from any container registry. It is a lightweight alternative to using Docker, Moby or rkt as the runtime for Kubernetes.
Documentation
General information
The following information was extracted from the containerfile and other sources.
| Summary | OCI-based implementation of Kubernetes Container Runtime Interface |
| Description | CRI-O is an implementation of the Kubernetes CRI. It is a lightweight, OCI-compliant runtime that is native to kubernetes. CRI-O supports OCI container images and can pull from any container registry. |
| Provider | Red Hat |
| Maintainer | Jhon Honce <jhonce@redhat.com> |
| License | GPLv2+ |
| Source location | https://github.com/kubernetes-incubator/cri-o |
Technical information
The following information was extracted from the containerfile and other sources.
| Repository name | openshift3/cri-o |
| Image version | v3.7.119 |
| Architecture | amd64 |
| Commit location | https://github.com/kubernetes-incubator/cri-o/commit/d7b7b82ae34ef8e9142e69784c5b9696922123dc |
| Usage | atomic install --system --system-package=no crio && systemctl start crio |
Use the following instructions to get images from a Red Hat container registry using registry service account tokens. You will need to create a registry service account to use prior to completing any of the following tasks.
Using OpenShift secrets
First, you will need to add a reference to the appropriate secret and repository to your Kubernetes pod configuration via an imagePullSecrets field.
Then, use the following from the command line or from the OpenShift Dashboard GUI interface.
Using podman login
Use the following command(s) from a system with podman installed
Using docker login
Use the following command(s) from a system with docker service installed and running
Use the following instructions to get images from a Red Hat container registry using your Red Hat login.
Using OpenShift
For best practices, it is recommended to use registry tokens when pulling content for OpenShift deployments.
Using podman login
Use the following command(s) from a system with podman installed
Using docker login
Use the following command(s) from a system with docker service installed and running
Use the following instructions to get images from a Red Hat container registry without providing authentication.
Using oc
A container image made to run with OpenShift platforms can either be pulled from the command line or from the OpenShift Dashboard GUI interface.
Using podman
Use the following command(s) from a system with podman installed
Using docker
Use the following command(s) from a system with docker service installed and running
Getting source containers
Source code is available for all Red Hat UBI-based images in the form of downloadable containers. Here are a few things you should know about Red Hat source containers.
- Although they are packaged as containers, source containers cannot be run. So instead of using podman pull to get them to your system, use the skopeo command.
- Source containers are named based on the binary containers they represent. So, for example, to get the source container for a particular standard RHEL UBI 8 container (registry.access.redhat.com/ubi8/ubi8.1-397) you simply append -source to get the source code container for that image (registry.access.redhat.com/ubi8/ubi8.1-397-source).
- The skopeo command is recommended for getting source containers. With skopeo, you copy a source container to a directory on your local system for you to examine.
- Once a source container is copied to a local directory, you can use a combination of tar,gzip, and rpm commands to work with that content.
Step one
Use skopeo to copy the source image to a local directory
Step two
Inspect the image
Step three
Untar the contents
Step four
Begin examining and using the content.
