Please enable JavaScript.
Coggle requires JavaScript to display documents.
OpenShift - Coggle Diagram
OpenShift
containers
set of one or more processes that are
isoleted
from the rest of the system
quick to reuse/deploy
low hardware footprint
environement isolation(independent)
portable
hard to maintain when number is large
podman
open source
manage container and container images (like docker)
interact with image registers (repositories)
uses image format defined by Open Container Initiative (OCI)
same command patterns like in Docker CLI
commands
sudo podman images
sudo podman pull
sudo podman search
sudo podman run
sudo podman build
sudo podman exec
command addons
-d - process in background
-t - terminal processing
-i - interactive
--home - specify container name
kubernetes
orchestration
scheduling based on the need
scaling up
scalling down
isolation
damage of one container does not affect other ones
Architecture:
Master Node - provide cluster services and controllers
Worker Node - perform work, pods are deployed here
Controller - watches resources and makes changes based on their state
architecture
pod
Dockerfile
Simple text file
Each line contains some instruction
Instructions are executed in order they appear
It is important to not use root as folder for dockerfiles
To omit to many layers of execution use '&&' in RUN commands
Sample Dockefile contains:
FROM - load image
LABEL - contain description (metadata)
MAINTAINER - person responsible (metadata)
RUN - execute command
EXPOSE - set the port to expose
ENV - declare enviroment variables
ADD - put files from "outside" (for example web) to container
COPY - copy files from host system to container
USER - specify user for commands
ENTRYPOINT - specify that files is executable
CMD - provides arguments for entrypoint
what is OpenShift
commands in openshift cluster
oc login
oc new-app
oc get
oc describe
oc export
oc create
oc edit
oc delete
oc exec
oc status
oc new-project
resource types
deployment config
build config
routes
Source to image S2I
Generates image directly from the git repository of the application. No need to create dockerfile
standard approach of deploying apps
disabilities
heavy, a lot of time needed to recreate in case of error/damage
dependent on the OS and libriaries
image
template for container
contains
runtimer environment
libraries
configuration files
repositories
RedHat Container Catalog
RedHar Quay
Docker Hub
