Linux:/etc/shells or /etc/os-release

 eks@GRDLUSAWSAMUT01:~$ cat /etc/os-release

NAME="Ubuntu"

VERSION="18.04.6 LTS (Bionic Beaver)"

ID=ubuntu

ID_LIKE=debian

PRETTY_NAME="Ubuntu 18.04.6 LTS"

VERSION_ID="18.04"

HOME_URL="https://www.ubuntu.com/"

SUPPORT_URL="https://help.ubuntu.com/"

BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"

PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"

VERSION_CODENAME=bionic

UBUNTU_CODENAME=bionic

eks@GRDLUSAWSAMUT01:~$ cat /etc/shells

# /etc/shells: valid login shells

/bin/sh

/bin/bash

/bin/rbash

/bin/dash

/usr/bin/tmux

/usr/bin/screen

eks@GRDLUSAWSAMUT01:~$

Linux:Kubectl : Add New User: Add User to secondary group : Change default Shell of a user

https://linuxize.com/post/how-to-create-users-in-linux-using-the-useradd-command/ 

sudo useradd -m username

ls -la /home/username/

https://careerkarma.com/blog/linux-add-user-to-group/

sudo usermod -a -G group_to_add username

https://www.tecmint.com/change-a-users-default-shell-in-linux/

 usermod --shell /bin/bash tecmint

admin@MACHINEVM01:~$ hostname -I

10.102.25.95 172.17.0.1 172.19.0.1

admin@MACHINEVM01:~$ getent passwd|grep admin

admin:*:16777219:16777220:Kaw, Karan:/home/admin:/bin/bash

admin@MACHINEVM01:~$ getent group|grep docker

docker:x:118:

admin@MACHINEVM01:~$ groups admin

admin : domain users BUILTIN\users

admin@MACHINEVM01:~$ sudo useradd -m eks

[sudo] password for admin:

admin@MACHINEVM01:~$ groups eks

eks : eks

admin@MACHINEVM01:~$ id eks

uid=1006(eks) gid=1006(eks) groups=1006(eks)

admin@MACHINEVM01:~$ getent group|grep eks

eks:x:1006:

admin@MACHINEVM01:~$ getent passwd|grep eks

eks:x:1006:1006::/home/eks:/bin/sh

admin@MACHINEVM01:~$ sudo usermod -a -G docker eks

admin@MACHINEVM01:~$ getent passwd|grep eks

eks:x:1006:1006::/home/eks:/bin/sh

admin@MACHINEVM01:~$ groups eks

eks : eks docker

admin@MACHINEVM01:~$

Docker-Compose Comands

apt install docker.io

apt install docker-compose

docker-compose up

docker-compose up -d

docker image ls

docker container ls

======================

docker ps

docker images

docker-compose -f docker-compose.yml down

docker-compose -f docker-compose.yml up -d

 netstat -tulpn|grep LISTEN

 

 tail -f nohup.out

 

Linux : Bash-Completion :Kubernetes

kubernetes.io/docs/tasks/tools/included/optional-kubectl-configs-bash-linux/

apt-get install bash-completion or yum install bash-completion

o find out, reload your shell and run type _init_completion. If the command succeeds, you're already set, otherwise add the following to your ~/.bashrc file:

source /usr/share/bash-completion/bash_completion

The kubectl completion script for Bash can be generated with the command 

kubectl completion bash




 kubectl rollout history deployment vea-cc  -n fda





Linux: SSH:Password for Few Users

https://serverfault.com/questions/285800/how-to-disable-ssh-login-with-password-for-some-users

https://serverfault.com/questions/307407/ssh-allow-password-for-one-user-rest-only-allow-public-keys

/etc/ssh/sshd_config
Match User <username>
PasswordAuthentication yes
Match all

/etc/ssh/sshd_config
Match User <username>
PasswordAuthentication yes
Match User all
PasswordAuthentication no




https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-key-pairs.html
https://stackoverflow.com/questions/15543032/connecting-aws-ec2-instance-asks-for-password-although-pem-file-is-provided
https://aws.amazon.com/premiumsupport/knowledge-center/new-user-accounts-linux-instance/
https://linuxize.com/post/how-to-list-users-in-linux/
https://serverfault.com/questions/797482/how-to-make-ec2-user-data-script-run-again-on-startup
https://aws.amazon.com/premiumsupport/knowledge-center/execute-user-data-ec2/
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/connect-to-serial-console.html

EC2: TAG : Shutdown

Instance Schedule

09:00 - 21:00 Mon - Sun

AWS : Userdata after every restart

aws.amazon.com/premiumsupport/knowledge-center/execute-user-data-ec2/

https://serverfault.com/questions/797482/how-to-make-ec2-user-data-script-run-again-on-startup

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#cloud-config

cloud_final_modules:

- [scripts-user, always]

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#!/bin/bash

/bin/echo "Hello World" >> /tmp/testfile.txt

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