DEV Community: Rupa Kumari

3. Linux commands

Rupa Kumari — Mon, 17 Oct 2022 04:15:48 +0000

who

Login name of user
Date and time of login
remote host name of user

whoami

Display system's username

Displays user identification (real and effective group ids)

groups

Displays the groups for which user belongs

Ways to become sudo user in Linus OS

sudo -i
sudo -s
sudo su -
su -root
su -

users

Displays username of all users currently logged in

clear

lastlog

detail of recent logged in user

File and Directory commands:

pwd

present working directory

list directories

mkdir

create directory

rmdir

remove directory

-p : refers for parent
-v : verbose output for the processed direct

touch

create file

/ root diretory
~ home directory

Installing packages
yum install package_name

Info about package
yum info package_name

Remove package
yum remove package_name

Installing package from a localfile
./filename

Disk usage command
du pathofdirectory

find out disk usage summary

du -h pathofdirectory

bring info in human readable format

du -sh nameofdirectory

find out total disk usage

ah -sh nameofdirectory

System and hardware information

uname -a

all user

uname -s

know kernel name

uname -r

release of kernel

uname -m

print architecture

uname -o

print operating system name

2. Linux Basics

Rupa Kumari — Mon, 10 Oct 2022 05:22:19 +0000

- Step 1
Install Oracle VM virtual box 6.1
https://www.virtualbox.org/

VM is an environment where we can host different systems.

- Step 2:
Install ISO Centos:
http://isoredirect.centos.org/centos/7/isos/x86_64/

- Step 3:
Configuration:

Click on New
Give any name ex. Centos
Type: Linux
Version: Red Hat 64 bit

memory size: atleast 2GB

- Step 4:
create a disk drive option
Hard disk file type: VDI(Virtual Disk image)

- Step 5:
Storage on physical hard disk: dynamically allocated

File location and size:
around 20GB

Click on Start of Centos, browse and import ISO Centos, Add.
select first option on screen as
Install CentOS 7

Linux OS:

Open source Operating System
software update,customization,distribution can be done in Linux.
Free to use
Cost of Linux is low
Large community support

Linus Sytem: package(Deb-RPM-YUM) --repo
RPM -RedHat Package Manager
YUM - Yellow Dog Updater

RPM

RPM can install only single package at a time.
RPM cannot resolve dependencies
cannot rollback with RPM

YUM

Yum can install multiple packages at a time
Yum can resolve dependencies automatically
Yum can rollback any changes

Assignment: Install all dependency for making Centos full screen
https://www.youtube.com/watch?v=Eo-DjIIwPvw

Update centos

sudo yum -y update

Hypervisor:
A hypervisor, also known as a virtual machine monitor or VMM, is software that creates and runs virtual machines (VMs). A hypervisor allows one host computer to support multiple guest VMs by virtually sharing its resources, such as memory and processing.

Types of Hypervisor:
between OS and Hardware
between OS and OS

Right click -> open new terminal
Linux Commands:

whoami
ls(list)

cd ~ whoami pwd ls ls -l cd Desktop mkdir inueron cd inueron touch devops.txt ls -l devops.txt chmod 777 devops.txt

User Group Other
7 7 7

Read - 4
Write - 2
Execute - 1
4+2+1 =7 (all)

chmod 4

1. Devops :Getting started

Rupa Kumari — Sat, 08 Oct 2022 20:07:59 +0000

Devops is a cultural practice by developers and operational team to use each other's tool,to smooth out the process of software delivery.

Core values
Core Ideas
Methods

Why Devops?
Agile methodology concerns about software methods,it doesn't cover server maintenace.

Devops covers these points:

Deploy faster - 50%
Less failure
Better recovery time

Team is in sync with each other.

Devops CAMS

C - Culture
talk to each other
people over process over tools
A - Automation
Automate process and do we really need to do it?
M - Measurement
Measure to improve
Replicate the stuff
Cloudwatch monitor
Measurement of client activity and take action on that.
S - Sharing
Share responsibilty,ownership ,feedback loop is important.

Devops follow three basic steps:

Flow thinking
What is already happening,or in process.
Amplify feedback
We get feedback from ops team timely.
Experiment and learn
New tool in launch and work

So basically,we have code,test,deploy under operation.

Dev team : plan,code,build and test

Ops team : release,deploy,operate and monitor

Some basic terminology to rememeber before getting started:

Provisioning
Server is ready with OS,software and networking.
Deployment
Adding or upgrading software on server
Orchestration
Coordinated operations on multiple systems.
Configuration management
Managing server configuration via files such as RAM,space,dependency software etc
Imperative(Procedural)
Commands to produce desired state
Declarative(Procedural)
Desired state is defined and tools will achieve it
Idempotent
Repeat execution and same result
Blue Green deployment
Identical deployment,used as switch
Continuous Integration
Build and unit test at every checkin
Continuous Delivery
Deploy on production live environment at every checkin
Continuous Deployment
After unit testing,deploy changes to production in small patches.

Thanks,
Rupa kumari