DevOps and Legacy Code

Unfortunately we can’t all work in startup companies. Some of use have to deal with legacy code bases. These are often structured as a monolith and tightly coupled. They typically are hard to build and deploy. You might think all the new DevOps practices and toys are not suitable for your context. You are wrong!

We will discuss strategies to work with legacy code and still use DevOps practices and tools. These include breaking up of monolithic structures, migrating data and monitoring systems that aren’t built to be monitored. We will show real-world examples of successful applications of these strategies.

While dealing with legacy code will still be painful, you will have some applicable ideas to relieve your pain.

Transcript

1. DevOps & Legacy
   DevOps Days London, 2019
   @DevOps_Events
   

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2. Why DevOps?
   

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3. How?
   

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4. Tight
   Coupling
   Specialists
   Manual
   Processes
   SS4CP*
   Brittleness
   Why is it so hard?
   *Simple Solutions for Complex Problems
   

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5. Tight
   Coupling
   Specialists
   Manual
   Processes
   SS4CP*
   Brittleness
   *Simple Solutions for Complex Problems
   Why is it so hard?
   Overwhelming
   

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6. Tight Coupling
   Comes in different flavours:
   ■ Architecture
   ■ Infrastructure
   ■ Code
   ■ ...
   the degree of interdependence
   between things*
   a measure of how closely
   connected two things* are
   the strength of the relationships
   between things*
   things*: components, infrastructure, modules, code, people...
   

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7. Tight Coupling
   Comes in different flavours:
   ■ Architecture
   ■ Infrastructure
   ■ Code
   ■ ...
   

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8. Tight Coupling
   Comes in different flavours:
   ■ Architecture
   ■ Infrastructure
   ■ Code
   ■ ...
   

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9. Tight Coupling
   Comes in different flavours:
   ■ Architecture
   ■ Infrastructure
   ■ Code
   ■ ...
   

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10. Tight Coupling
    Comes in different flavours:
    ■ Architecture
    ■ Infrastructure
    ■ Code
    ■ ...
    

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11. Tight Coupling
    Comes in different flavours:
    ■ Architecture
    ■ Infrastructure
    ■ Code
    ■ ...
    

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12. Tight Coupling
    Comes in different flavours:
    ■ Architecture
    ■ Infrastructure
    ■ Code
    ■ ...
    

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13. Tight Coupling
    Comes in different flavours:
    ■ Architecture
    ■ Infrastructure
    ■ Code
    ■ ...
    public class Foo {
    public void foo() {
    new Bar().bar();
    }
    }
    var GLOBAL_SHARED_VALUE = 23
    import http.client
    con = http.client
    .HTTPSConnection("devops-events.de")
    con.request("GET", "/")
    res = connection.getresponse()
    print("Status: {} and reason: {}"
    .format(res.status, res.reason))
    connection.close()
    
    xmlns:soap=...
    
    
    

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14. Baby Steps
    ■ Big Bangs don’t work.
    ■ There is always the next
    baby step.
    ■ Legacy code took time to
    grow bad. It will take time
    to fix it.
    

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15. About Us
    Peter Götz
    peter@devops-events.de
    @petersgoetz
    Save 50% for our next DevOps Lab training
    https://www.devops-events.de/trainings/devops-lab
    Buy one ticket and bring a friend or colleague
    for free (coupon code “2-4-1”)
    Oliver Hankeln
    oliver@devops-events.de
    @mydalon
    

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16. Credits
    ■ @alexagorn (https://unsplash.com/photos/smuS_jUZa9I)
    ■ @matthew_t_rader (https://unsplash.com/photos/bZbd02TN9t0)
    ■ @jentheodore (https://unsplash.com/photos/qRtLPwRlXxI)
    ■ @harlsta (https://unsplash.com/photos/ouyjDk-KdfY)
    ■ @byrawpixel
    (https://www.pexels.com/photo/baby-s-standing-on-gray-floor-rug-1776136/)
    

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