cri-o/transfer.md

cri-o Usage Transfer

This document outlines useful information for ops and dev transfer as it relates to infrastructure that utilizes cri-o.

Operational Transfer

Abstract

The crio daemon is intended to provide the CRI socket needed for Kubernetes to use for automating deployment, scaling, and management of containerized applications (See the document for configuring kubernetes to use cri-o for more information on that). Therefore the crioctl command line is a client that interfaces to the same grpc socket as the kubernetes daemon would, for talking to the crio daemon. In many ways crioctl is only as feature rich as the Kubernetes CRI requires. There are additional tools e.g. kpod and buildah that provide a feature rich set of commands for all operational needs in a Kubernetes environment.

System Tools

Many traditional tools will still be useful, such as pstree, nsenter and lsns. As well as some systemd helpers like systemd-cgls and systemd-cgtop are still just as applicable.

Equivalents

For many troubleshooting and information collection steps, there may be an existing pattern. Following provides equivalent with cri-o tools for gathering information or jumping into containers, for operational use.

Existing Step	CRI-O (and friends)
docker exec	crioctl ctr exec
docker info	kpod info
docker inspect	kpod inspect
docker logs	kpod logs
docker ps	crioctl ctr list or runc list
docker stats	kpod stats or crioctl ctr status

If you were already using steps like kubectl exec (or oc exec on OpenShift), they will continue to function the same way.

Development Transfer

There are other equivalents for these tools

Existing Step	CRI-O (and friends)
docker build	buildah bud
docker cp	kpod mount ***
docker diff	kpod diff
docker export	kpod export
docker history	kpod history
docker images	kpod images
docker kill	kpod kill
docker load	kpod load
docker pause	kpod pause
docker ps	kpod ps
docker pull	kpod pull
docker push	kpod push
docker rename	kpod rename
docker rm	kpod rm
docker rmi	kpod rmi
docker save	kpod save
docker stop	kpod stop
docker tag	kpod tag
docker unpause	kpod unpause
docker version	kpod version
docker wait	kpod wait

*** Use mount to take advantage of the entire linux tool chain rather then just cp. Read here for more information.