Scaling and Autoscaling:

Horizontal scaling adds more machines into the system while vertical scaling add more resources to existing system.

Quota:

Quota is a set a limit from project level

#oc create quota --help | more

Resource Quota:

#oc create resourcequota --help | more

We can set a limit for the resource through resourcequota.

* CPU

* Memory

* Number of Deployments

* number of services

* number of service accounts

* config Map

* Service accounts

* number of Pods

It will allow the restriction of users and avoid over provision.

Example:

#oc create quota my-quota --hard=cpu=1,memory=1G,pods=2,services=3,replicationcontroller=1,secrets=5,persistentvolumeclaims=10 -n testquota

List resource under core group:

#oc api-resources --api-group="" --namespaced=true

Resource group:

#oc create resourcequota test --hard=count/pods=1

Utilization of resources in OCP cluster:

#oc adm top nodes

Create an APP for testing purpose:

#oc new-app --name myapp --image=registry.example.com:8443/helloworld-nginx

Set a resources for the app

#oc set resources deployment myapp --limits=cpu=200m,memory=300M --requests=cpu=100m,memory=200M

#oc set resources dc/myapp --limits=memory=60Mi --requests=memory=20Mi

Monitoring the process of resources:

#watch oc get all

List the events with timestamp:

#oc get events --sort-by=.metadata.creationTimestamp

Delete a pod:

#oc delete pod -l deploymentconfig=myapp1

Scale out the pods:

#oc scale dc/myapp1 --replicas=5

Create a quota:

#oc create quota my-quota --hard=limits.cpu=2,limits.memory=200Mi,requests.cpu=1,requests.memory=100Mi,pods=3,services=10

Authentication and authorization:

Authentication will check whether user has access or not from the system

Authorization : It will user has a right role or access for application side.

Openshift has a two roles 1) cluster role 2) Project role

#oc get clusterrolebinding

#oc get rolebinding

1) Create users

2) Integrate users with OCP

3) How to assign roles as per requirement of user

4) How to create groups

5) How to add users to the groups

Create a user through htpasswd

#htpasswd -c -B -b filename username password

-B option is encrypied the password

-b - single line command

#oc get secret -n openshift-config

Secret has 3 types such as Docker-registry, generic and tls.

#oc create secret generic mysecret --from-file=test -n openshift-config

Create users

#htpasswd -B -b myusers test1 passwd

Integrate users with OCP environment

#oc create secret generic mysecret --from-file=htpasswd=myusers -n openshift-config

#oc get secret mysecret -n openshift-config -o yaml

#oc get oauth cluster -o yaml > oauth.yaml

#oc replace -f oauth.yaml

Testing the login with OCP environment

#oc login -u test -p passwd

#oc new-project testing1

#oc describe project testing1

Edit the yaml file through vim with GUI

#vi .vimrc

autocmd FileType yaml setlocal ts=2 cuc curl

cuc - cursal problem

curl - cursal line

aicuc - Auto indentation 

We can able to get a roles details under clusterrolebinding:

#oc get clusterrolebinding | grep -i cluster-admin

#oc describe clusterrolebinding cluster-admin

Delete a role under clusterrolebinding:

#oc delete clusterrolebinding cluster-admin

Do view the policy

#oc adm policy

Default role of cluster and project policy:

Cluster - Cluster-admin and self-provisioner

Project - admin, edit and view

Adding a user into role

#oc adm policy add-cluster-role-to-user cluster-admin username

Remove a role from user

#oc adm policy remove-cluster-role-from-group self-provisioner user

#oc adm policy remove-cluster-role-from-group self-provisioner system:authenticated:oauth

System admin will use to check the remote port status for any application / system port issue.

We can check the port status with 5 ways.

Use nc command

#nc -zv IPaddress Portnumber

Use nmap command 

#nmap IPaddress -p portnumber

Use telnet command 

#telnet IPaddress portnumber

Use python module:

#python telnet IPaddress portnumber

Use curl command

curl -v telnet IPaddress:portnumber