~/.aws ~.aws/confg ~./aws/credentials IAM Access Key/Secret Key

 aws configure

aws configure --profile karan

aws s3 ls 

aws s3 ls profile --fubar

vi ~/.aws/config

vi ~/.aws/credentials

aws iam list-users --profile default

[ec2-user@ip-172-31-16-83 .aws]$ aws iam list-users

An error occurred (AccessDenied) when calling the ListUsers operation: User: arn:aws:sts::061116847625:assumed-role/S3FullAccessFromEC2NoCredReq/i-0622cebe406df06cd is not authorized to perform: iam:ListUsers on resource: arn:aws:iam::061116847625:user/

Mount EBS to EC2

https://devopscube.com/mount-ebs-volume-ec2-instance/

sudo cp /etc/fstab /etc/fstab.bak

/dev/xvdf       /hdd2   ext4    defaults,nofail        0       0

* chown, chmod, chgrp, chattr, id 2775 vs 775

 

EBS vs EFS - AWS - Elastic Block Storage vs Elastic File System

https://aws.amazon.com/getting-started/tutorials/create-network-file-system/

https://www.missioncloud.com/blog/resource-amazon-ebs-vs-efs-vs-s3-picking-the-best-aws-storage-option-for-your-business

EBS  --------> 1 EC2 Instance is mapped to EBS - Block Level Storage

EFS ----------> Multiple EC2 Instances - Mounted to this File System - Common across multiple Apps

The main differences between EBS and EFS is that EBS is only accessible from a single EC2 instance in your particular AWS region, while EFS allows you to mount the file system across multiple regions and instances.

S3 -->  S3 is Object Level storage. S3 is not limited to EC2, Its linked to CloudFront through which many Media etc are hosted there.

IPTABLES, Firewall, Actual Firewall + Security Group - AWS

https://www.tecmint.com/fix-no-route-to-host-ssh-error-in-linux/

https://www.cyberciti.biz/faq/how-to-list-all-iptables-rules-in-linux/                            

sudo nmap -p 6900,25,22,8080,21000,7856,9084 10.79.197.70

sudo iptables -S

sudo nmap -p 6900,25,22,8080,21000,7856,9084 10.79.197.70

https://www.e2enetworks.com/help/knowledge-base/how-to-open-ports-on-iptables-in-a-linux-server/#step-1-list-the-current-iptables-rules

sudo iptables -D IN_public_allow -p tcp -m tcp --dport 7856 -m conntrack --ctstate NEW,UNTRACKED -j ACCEPT

sudo iptables -A IN_public_allow -p tcp -m tcp --dport 7856 -m conntrack --ctstate NEW,UNTRACKED -j ACCEPT

Zscaler Private Access (ZPA) , CHATTR Linux, Immuable, VPC -> PrefixList

https://superuser.com/questions/1647896/putty-key-format-too-new-when-using-ppk-file-for-putty-ssh-key-authentication

VPC -> PrefixList
https://docs.aws.amazon.com/vpc/latest/userguide/managed-prefix-lists.html

https://aws.amazon.com/marketplace/pp/prodview-epy3md7fcvk4g?ref=cns_srchrow

https://www.fugue.co/blog/cloud-network-security-101-aws-security-groups-vs-nacls

https://www.javatpoint.com/aws-nacl-vs-security-group

https://mylearningsonline.com/aws-services/aws-vpc-security-group-nacl/

https://www.davidc.net/sites/default/subnets/subnets.html

http://www.cronmaker.com/

https://www.baeldung.com/linux/grep-sed-awk-differences#1-basic-syntax-1

chattr +i      [To make it immutable, Its not related to access permissions] - Change Attribute

SetUserBit

SetGroupBit                       chmod 2775          chmod +ug rw

which                                 Which executable

whereis

https://stackoverflow.com/questions/39239276/how-to-enable-a-directory-listing-in-apache-web-server

Azure Pipelines, YAML Schema

https://docs.microsoft.com/en-us/azure/devops/pipelines/yaml-schema?view=azure-devops&tabs=schema%2Cparameter-schema

https://docs.microsoft.com/en-us/azure/devops/pipelines/get-started/key-pipelines-concepts?view=azure-devops

https://docs.microsoft.com/en-us/azure/devops/pipelines/repos/azure-repos-git?view=azure-devops&tabs=yaml#ci-triggers

https://faun.pub/reduce-your-build-time-using-caching-in-azure-pipelines-7a7bd0201cee

Resources

Trigger

Pipeline -> Stage(Implicit) -> Jobs -> Steps [Task, Script, Checkout]

jobs:

- job: Job_1

  displayName: Agent job 1   

  pool:

    vmImage: ubuntu-latest

  steps:

    -script: echo "Hello World"

pool:

  name: Default

  demands: SpecialSoftware # Check if SpecialSoftware capability exists

  

  

stages:

- stage: A

  jobs:

  - job: A1

  - job: A2

- stage: B

  jobs:

  - job: B1

  - job: B2  

https://docs.microsoft.com/en-us/azure/devops/pipelines/process/phases?view=azure-devops&tabs=yaml

stages:

- stage: A

# stage B runs if A fails

- stage: B

  condition: failed()

# stage C runs if B succeeds

- stage: C

  dependsOn:

  - A

  - B

  condition: succeeded('B')

If you choose to specify a pool at the stage level, then all jobs defined in that stage will use that pool unless otherwise specified at the job-level.

stages:

- stage: A

  pool: StageAPool

  jobs:

  - job: A1 # will run on "StageAPool" pool based on the pool defined on the stage

  - job: A2 # will run on "JobPool" pool

    pool: JobPool

jobs:

- job: Foo

  steps:

  - script: echo Hello!

    condition: always() # this step will always run, even if the pipeline is canceled

- job: Bar

  dependsOn: Foo

  condition: failed() # this job will only run if Foo fails

https://docs.microsoft.com/en-us/azure/devops/pipelines/agents/hosted?view=azure-devops&tabs=yaml

jobs:

- job: Debug

  steps:

  - script: echo hello from the Debug build

- job: Release

  dependsOn: Debug

  steps:

  - script: echo hello from the Release build

You can organize pipeline jobs into stages. Stages are the major divisions in a pipeline: "build this app", "run these tests", and "deploy to pre-production" are good examples of stages. They are logical boundaries in your pipeline where you can pause the pipeline and perform various checks.

Pipeline > Stages >Stage>Steps>Step

jobs:

- job: A

  steps:

  - bash: echo "A"

- job: B

  steps:

  - bash: echo "B"

  

  

  If you organize your pipeline into multiple stages, you use the stages keyword.

If you choose to specify a pool at the stage level, then all jobs defined in that stage will use that pool unless otherwise specified at the job-level

stages:

- stage: A

  jobs:

  - job: A1

  - job: A2

- stage: B

  jobs:

  - job: B1

  - job: B2

  

  When you define multiple stages in a pipeline, by default, they run sequentially in the order in which you define them in the YAML file. The exception to this is when you add dependencies. With dependencies, stages run in the order of the dependsOn requirements

  stages:

- stage: string

  dependsOn: string

  condition: string

  -----------------------------------------------------------

  You can organize your pipeline into jobs. Every pipeline has at least one job. A job is a series of steps that run sequentially as a unit. In other words, a job is the smallest unit of work that can be scheduled to run.

  

  In the simplest case, a pipeline has a single job. In that case, you do not have to explicitly use the job keyword

  

  jobs:

- job: myJob

  timeoutInMinutes: 10

  pool:

    vmImage: 'ubuntu-16.04'

  steps:

  - bash: echo "Hello world"

  

  

  /usr/lib/jvm/adoptopenjdk-11-hotspot-amd64

 # update-alternatives --config java

          update-alternatives --list java

          echo ls /etc/alternatives

          ls /etc/alternatives

  

  

https://docs.microsoft.com/en-us/azure/devops/pipelines/build/variables?view=azure-devops&tabs=yaml

https://faun.pub/reduce-your-build-time-using-caching-in-azure-pipelines-7a7bd0201cee