SSH & DevOps Crash Course Snippets

ssh.md

SSH Cheat Sheet

This sheet goes along with this SSH YouTube tutorial

Login via SSH with password (LOCAL SERVER)

$ ssh brad@192.168.1.29

Create folder, file, install Apache (Just messing around)

$ mkdir test

$ cd test

$ touch hello.txt

$ sudo apt-get install apache2

Generate Keys (Local Machine)

$ ssh-keygen

Add Key to server in one command

> cat ~/.ssh/id_rsa.pub | ssh brad@192.168.1.29 "mkdir -p ~/.ssh && chmod 700 ~/.ssh && cat >> ~/.ssh/authorized_keys"

Create & copy a file to the server using SCP

$ touch test.txt $ scp ~/test.txt brad@192.168.1.29:~

DIGITAL OCEAN

Create account->create droplet

Create Keys For Droplet (id_rsa_do)

$ ssh-keygen -t rsa

Add Key When Creating Droplet

Try logging in

$ ssh root@doserver

If it doesn't work

$ ssh-add ~/.ssh/id_rsa_do (or whatever name you used)

Login should now work

$ ssh root@doserver

Update packages

$ sudo apt update

$ sudo apt upgrade

Create new user with sudo

$ adduser brad

$ id brad

$ usermod -aG sudo brad

$ id brad

Login as brad

> ssh brad@doserver

We need to add the key to brads .ssh on the server, log back in as root

$ ssh root@doserver

$ cd /home/brad

$ mkdir .ssh

$ cd .ssh

$ touch authorized_keys

> sudo nano authorized_keys (paste in the id_rsa_do.pub key, exit and log in as brad)

Disable root password login

$ sudo nano /etc/ssh/sshd_config

Set the following

PermitRootLogin no

PasswordAuthentication no

Reload sshd service

$ sudo systemctl reload sshd

Change owner of /home/brad/* to brad

$ sudo chown -R brad:brad /home/brad

May need to set permission

$ chmod 700 /home/brad/.ssh

Install Apache and visit ip

$ sudo apt install apache2 -y

Github

Generate Github Key(On Server)

$ ssh-keygen -t rsa (id_rsa_github or whatever you want)

Add new key

$ ssh-add /home/brad/.ssh/id_rsa_github

If you get a message about auth agent, run this and try again

```$ eval `ssh-agent -s````

Clone repo

$ git clone git@github.com:bradtraversy/react_otka_auth.git

Install Node

$ curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash -

$ sudo apt-get install -y nodejs

Install Dependencies

$ npm install

Start Dev Server and visit ip:3000

$ npm start

Build Out React App

$ npm run build

Move static build to web server root

$ sudo mv -v /home/brad/react_otka_auth/build/* /var/www/html

Multiple SSH AuthKeys

Step 1: Generate first ssh key Type the following command to generate your first public and private key on a local workstation. Next provide the required input or accept the defaults. Please do not change the filename and directory location.

workstation 1 $ ssh-keygen -t rsa

Finally, copy your public key to your remote server using scp

workstation 1 $ scp ~/.ssh/id_rsa.pub user@remote.server.com:.ssh/authorized_keys

Step 2: Generate next/multiple ssh key

1. Login to 2nd workstation
2. Download original the authorized_keys file from remote server using scp:

workstation 2 $ scp user@remote.server.com:.ssh/authorized_keys ~/.ssh

3. Now create the new pub/private key:

workstation 2 $ ssh-keygen -t rsa

4. Now you have new public key. APPEND this key to the downloaded authorized_keys file using cat command:

workstation 2 $ cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

5. Finally upload authorized_keys to remote server again:

workstation 2 $ scp ~/.ssh/authorized_keys user@remote.server.com:.ssh/

You can repeat step 2 for each user or workstations for remote server.

Step 3: Test your setup Now try to login from Workstation 1, 2 and so on to remote server. You should not be asked for a password:

workstation 1 $ ssh user@remote.server.com

workstation 2 $ ssh user@remote.server.com