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A 10,000ft view of the world
Below are a few terms we will be using and a brief definition:
- General Topics:
- Software: A program that runs on a computer.
- Operating System: Computer software that manages other software.
- GNU/Linux: A free Operating System.
- Computer Security: Like physical security but harder to solve with a baseball bat.
- Virtual Machine: A computer emulated in software.
- Containers: Not virtual machines, but basically virtual machines.
- Version Control: A way to track changes and contributions to a project.
- Continuous Integration: Releasing updates continuously.
- FOSS: Free (and Libre) Open Source Software. Free as in Speech, not Free as in Pizza (but that too usually).
- ‘The Cloud’: Computers somewhere else.
- Docker: Software that manages Linux containers
Some notes about notation...
Just like a textbook, we have some unique notation you should be aware of. The following is a short list of key notation used in DOBC.
- Variable (use whatever word you like here e.g., foo, bar, baz)
$ONE_VARIABLE_NOTATION <another notation for variables>
- Literal (copy this exactly): copy_me_exactly
- Comments (parts of the code just for humans)
this_is(code) # everything after the octothorp is a comment!
other_code(line) // This can also be a comment. It depends on the // language!
We try to write code-blocks so you can copy them verbatim into a file or into your terminal and hit Enter to see it run (unless it’s psuedo code!)
Every language has it’s own comment symbol. The common ones are #, //, and /* ... */ . If you see that in a code-block it denotes a comment block.
#! /usr/bin/env python # This is a code block. # Most of the time you can copy this code and run it exactly as is. # It should be clear Where it 'goes' and how to run it based on # context. print('Hello world!')
You can copy the above script into a file named <whatever you want>.py and run it with python <whatever you want>.py
Shell commands are annotated with a $. For instance:
# Copy the text after `$` into your terminal & press enter. $ echo Hello World
Trick question: how would you read this
#!/bin/python dogs = ['$BREED_ONE', '$BREED_TWO', '$BREED_THREE'] for breed in dogs: print(breed)
$BREED_ONE $BREED_TWO $BREED_THREE
- Secure Shell (SSH) provides a secure channel to access a Linux machine remotely via command line.
- It’s a primary tool for almost every DevOps engineer
- Designed as a replacement to Telnet which provides unsecured remote shell access
- Allows for password logins and private/public key-based logins which are more secure
- Some tricks you can do with SSH
If you are taking the course exclusively online you will need setup Docker on your own computer. For more information jump down to the Docker Setup section of this lesson.
If you are taking DOBC in person we are able to offer you credentials to the OSU OSL Student Cloud. More information in the Lecture Setup section.
There are a variety of ways to run Linux!
- Dual-boot Windows+Linux
- Virtual Machine (VMWare, Virtualbox, cloud server, etc)
- Container (Docker)
- Windows Linux Subsystem
We suggest you install Docker, a tool which makes it easy to run small Linux Containers on your system in a safe sandbox without requiring to install Linux on your own machine. This is the same setup we used in the lecture.
Make sure you read the install documentation for Docker to ensure your system supports running it and have the required BIOS settings enabled.
After you have it installed, run this to start a container:
$ docker run -p 2222:22 -h dobc --rm --name=dobc1 -d \ -e DOBC_PASSWORD=passw04d osuosl/dobc-centos
Using your SSH client, connect to hostname localhost and port 2222. Login using the username dobc and the password passw04d (as set above). Go ahead and accept the host key and login. Once in, you’ll be logged into a CentOS based container.
Alternatively, you can also run the docker container in an interactive mode instead of connecting to it via ssh:
$ docker run -h dobc --rm --name=dobc1 -it osuosl/dobc-centos bash
You can log out by typing exit and then enter which will stop the container.
Feel free to try other Docker images, some that we recommend include:
To run those, do the following:
$ docker run -it --rm <docker image name> bash
Instead of using Docker, you can also run a Linux Virtual Machines on your computer. This will give you a full Linux environment as if it were on a real machine.
After you get Vagrant and either VirtualBox or VMWare installed, clone our vagrant repo (make sure you install Git first!) and then start the VM:
$ git clone https://github.com/DevOpsBootcamp/vagrant.git $ cd vagrant $ vagrant up $ vagrant ssh
If you have any questions or problems, Google is your friend! If that does not work, contact us DevOps Bootcamp and we’ll help you as best we can.
The Windows Subsystem for Linux (Bash on Windows) allows you to run userspace Linux software on Windows, while using less resources than a virtual machine.
If you installed the Fall Creators Update for Windows 10, you can install one or more Linux distributions through the Windows Store.
Challenge Change your password on your Linux machine.
To get aquainted with your new Virtual Machine we are going to change your users password. This is just like changing your password on your personal laptop (you’ve done that before right?) but entirely via the terminal, no windows or click-buttons at all.
Start by logging in (outlined in the previous slides). Then run the following command:
$ passwd Changing password for user <user>. Changing password for <user>. (current) UNIX password: # Enter old password, hidden New password: # Enter new password, also hidden Retype new password: passwd: all authentication tokens updated successfully.
In the next lesson we’re going to go over how to do almost everything via your terminal from editing files to browsing the web!
Don’t forget: when you login next time, use the new password you just set.
- More information on Linux Containers and Virtual Machines.
- Install Putty if you want to access a remote Linux box.
- Install Docker if you want to run a local Linux container
- Install Vagrant if you want to run a local Linux Virtual machine.
- Install VirtualBox in addition to Vagrant for local virtual machines.
- Install VMWare in addition to Vagrant for local virtual machines.
- Windows Subsystem for Linux if you want to use Linux without VM overhead.