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Shadow Cipher

What is system Administration?

Course Introduction

  • System Administration
    The field in IT that’s responsible for maintaining reliable computer systems in a multi-user environment.

What is Systems Administratiuon?

  • IT infrastrure encompasses the software, the hardware, network, an services required for an organization to operate in an enterprize IT environment.

  • Sysadmins

  • Network administrators

  • Database administratrs

Servers Revisited

  • A sysadmin is responsible for their company’s IT services.

  • Email

  • File Storage

  • Running a website

  • Servers
    Software or a machine that provides services to other software or machines.

  • Email servers

  • SSH servers

  • Tower servers

  • Rack servers

  • Blade servers

  • Clients

  • KVM Switch - Mac, PC, Linux

The Cloud

  • Cloud Computing

  • Data Center
    A facility that stored hundreds, if not thousands of servers.

  • Data centers -> File storage -> Security Updates, Server Hardware, Software Updates

  • Cost

  • Dependency

Organization Policies

  • Should users be allowed to install software?

  • Should users have complex passwords with sertain requirements?

  • Symbols

  • Random numbers

  • Letters

  • Should users be allowed to view non-work-related website, like facebook?

  • If you hand out a company phone to an employee, should you set a device password?

IT Infrastrure services?

  • File Storage
  • Email
  • Web content

User and Hardware Provoisioning

  • Provoisioning

  • hardware Lifecycle

  • Procurement -> Deployment -> Maintenance -> Retirement

Routine Maintenance

  • Batch update

Vendors

Troubleshooting and Managing Issues

  • Troubleshooting
  • Customer service

In Case of Fire, Break Glass

With Great Power Comes Great responsibility

  • Avoid using administrator rights for tasks that don’t require them.

  • sudo ls

  • Respect the privacy of others

  • Think before you type

  • plan ahead

  • Serves as documentation

  • Script

  • Start-Transcript

  • recordMyDesktop

  • Reverting to the previous state is called a rollback

Never test in Production

  • production
    The parts of the infrastruture where a certain service is executed and served to its users

  • Test enviroment
    A virtual machine running the same configuration environment, but isn’t actually serving any users of the service

  • Secondary or stand-by machine
    This machine nwill be exactly the same as a production machine, but won’t receive any traffic from actual users untill you enable it to do so

  • For even bigger services, when you have lots of mservers providing the service, you may want to have canaries.

Assesing Risk

  • In general , the more users your service reaches, the more you’ll want to ensure that changes aren’t disruptive

  • The more important your service is to your comapny’s operations, the more you’ll work to keep the services up.

Fixing Things the right way?

  • Reproduction case
    Creating a roadmap to retrace the steps that led the user to an enexpected outcome

  • What steps did you take to get to this points?

  • What’s the unexpected or bad result?

  • what’s the expected result?

  • After applying your fix, retrace the same steps that took you to the bad experience. If your fix worked, the expected experience should now take place