Help! I've created a serverless monolith! - CloudBrew

Slides for my CloudBrew 2022 session.
I talked about serverless monoliths, how unmaintainable apps cause problems with agility and how to measure agility. How accidental complexity can be reduced or moved, and I offered three strategies how to breakup a serverless monolith based on, bounded context, resilience, and scalability.

Transcript

1. @MarcDuiker
   

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2. @MarcDuiker 2
   Marc Duiker
   Sr Developer Advocate
   

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3. @MarcDuiker 3
   

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4. @MarcDuiker
   

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5. @MarcDuiker 5
   

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6. @MarcDuiker 6
   

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7. @MarcDuiker 7
   

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8. @MarcDuiker 8
   

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9. @MarcDuiker 9
   https://en.wikipedia.org/wiki/Monolithic_application
   “In software engineering, a monolithic
   application describes a software application
   that is designed without modularity.”
   

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10. @MarcDuiker 10
    https://en.wikipedia.org/wiki/Modularity
    “…modularity is the degree to which a
    system's components may be separated and
    recombined, often with the benefit of
    flexibility and variety in use.”
    

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11. @MarcDuiker 11
    App Server DB Server
    

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12. @MarcDuiker 12
    Function App
    Function App Queue Storage
    

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13. @MarcDuiker 13
    Function App
    Function App Queue Storage
    

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14. @MarcDuiker 14
    

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15. @MarcDuiker 15
    

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16. @MarcDuiker 16
    

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17. @MarcDuiker
    

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18. @MarcDuiker 18
    https://martinfowler.com/articles/agileStory.html
    “We eventually agreed on "agile" as we felt
    that captured the adaptiveness and
    response to change which we felt was so
    important to our approach…”
    

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19. @MarcDuiker 19
    

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20. @MarcDuiker 20
    

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21. @MarcDuiker 21
    

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22. @MarcDuiker 22
    

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23. @MarcDuiker
    

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24. @MarcDuiker 24
    

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25. @MarcDuiker 25
    Task on backlog Work started Work completed
    

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26. @MarcDuiker 26
    https://www.atlassian.com/incident-management/kpis/common-metrics
    

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27. @MarcDuiker 27
    https://www.atlassian.com/incident-management/kpis/common-metrics
    

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28. @MarcDuiker 28
    https://www.atlassian.com/incident-management/kpis/common-metrics
    

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29. @MarcDuiker 29
    

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30. @MarcDuiker 30
    

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31. @MarcDuiker 31
    https://learn.microsoft.com/en-us/azure/azure-functions/functions-host-json
    

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32. @MarcDuiker 32
    

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33. @MarcDuiker 33
    https://learn.microsoft.com/en-us/azure/azure-functions/functions-deployment-slots
    

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34. @MarcDuiker 34
    Function App
    Website Queue
    

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35. @MarcDuiker 35
    

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36. @MarcDuiker
    

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37. @MarcDuiker 37
    Caused by the nature of the
    (business) problem.
    Can’t be easily reduced.
    Caused by decisions we make related
    to architecture, frameworks,
    packages, code style etc.
    Can be reduced.
    https://en.wikipedia.org/wiki/Programming_complexity
    

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38. @MarcDuiker 38
    https://en.wikipedia.org/wiki/Programming_complexity
    Caused by decisions we make related
    to architecture, frameworks,
    packages, code style etc.
    Can be reduced.
    Caused by the nature of the
    (business) problem.
    Can’t be easily reduced.
    

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39. @MarcDuiker 39
    

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40. @MarcDuiker 40
    

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41. @MarcDuiker 41
    

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42. @MarcDuiker 42
    

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43. @MarcDuiker 43
    

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44. @MarcDuiker 44
    

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45. @MarcDuiker 45
    

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46. @MarcDuiker 46
    

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47. @MarcDuiker 47
    

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48. @MarcDuiker 48
    

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49. @MarcDuiker 49
    public static class ChainingExample
    {
    [FunctionName(nameof(ChainingExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var resultA = await context.CallActivityAsync(
    nameof(ActivityFunctionA),
    null);
    var resultB = await context.CallActivityAsync(
    nameof(ActivityFunctionB),
    resultA);
    var resultC = await context.CallActivityAsync(
    nameof(ActivityFunctionC),
    resultB);
    return resultC;
    }
    }
    

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50. @MarcDuiker 50
    public static class ChainingExample
    {
    [FunctionName(nameof(ChainingExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var resultA = await context.CallActivityAsync(
    nameof(ActivityFunctionA),
    null);
    var resultB = await context.CallActivityAsync(
    nameof(ActivityFunctionB),
    resultA);
    var resultC = await context.CallActivityAsync(
    nameof(ActivityFunctionC),
    resultB);
    return resultC;
    }
    }
    

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51. @MarcDuiker 51
    public static class ChainingExample
    {
    [FunctionName(nameof(ChainingExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var resultA = await context.CallActivityAsync(
    nameof(ActivityFunctionA),
    null);
    var resultB = await context.CallActivityAsync(
    nameof(ActivityFunctionB),
    resultA);
    var resultC = await context.CallActivityAsync(
    nameof(ActivityFunctionC),
    resultB);
    return resultC;
    }
    }
    

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52. @MarcDuiker 52
    public static class ChainingExample
    {
    [FunctionName(nameof(ChainingExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var resultA = await context.CallActivityAsync(
    nameof(ActivityFunctionA),
    null);
    var resultB = await context.CallActivityAsync(
    nameof(ActivityFunctionB),
    resultA);
    var resultC = await context.CallActivityAsync(
    nameof(ActivityFunctionC),
    resultB);
    return resultC;
    }
    }
    

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53. @MarcDuiker 53
    public static class ChainingExample
    {
    [FunctionName(nameof(ChainingExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var resultA = await context.CallActivityAsync(
    nameof(ActivityFunctionA),
    null);
    var resultB = await context.CallActivityAsync(
    nameof(ActivityFunctionB),
    resultA);
    var resultC = await context.CallActivityAsync(
    nameof(ActivityFunctionC),
    resultB);
    return resultC;
    }
    }
    

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54. @MarcDuiker 54
    

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55. @MarcDuiker 55
    public static class FanOutFanInExample
    {
    [FunctionName(nameof(FanOutFanInExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var tasks = new List>();
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionA),
    null));
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionB),
    null));
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionC),
    null));
    var results = await Task.WhenAll(tasks);
    return results;
    }
    

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56. @MarcDuiker 56
    public static class FanOutFanInExample
    {
    [FunctionName(nameof(FanOutFanInExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var tasks = new List>();
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionA),
    null));
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionB),
    null));
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionC),
    null));
    var results = await Task.WhenAll(tasks);
    return results;
    }
    

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57. @MarcDuiker 57
    public static class FanOutFanInExample
    {
    [FunctionName(nameof(FanOutFanInExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var tasks = new List>();
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionA),
    null));
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionB),
    null));
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionC),
    null));
    var results = await Task.WhenAll(tasks);
    return results;
    }
    

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58. @MarcDuiker 58
    public static class FanOutFanInExample
    {
    [FunctionName(nameof(FanOutFanInExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var tasks = new List>();
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionA),
    null));
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionB),
    null));
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionC),
    null));
    var results = await Task.WhenAll(tasks);
    return results;
    }
    

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59. @MarcDuiker 59
    public static class FanOutFanInExample
    {
    [FunctionName(nameof(FanOutFanInExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var tasks = new List>();
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionA),
    null));
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionB),
    null));
    tasks.Add(context.CallActivityAsync(
    nameof(ActivityFunctionC),
    null));
    var results = await Task.WhenAll(tasks);
    return results;
    }
    

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60. @MarcDuiker 60
    

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61. @MarcDuiker 61
    public static class SubOrchestratorExample
    {
    [FunctionName(nameof(SubOrchestratorExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var resultA = await context.CallSubOrchestratorAsync(
    nameof(SubOrchestratorA),
    null);
    var resultB = await context.CallSubOrchestratorAsync(
    nameof(SubOrchestratorB),
    resultA);
    var resultC = await context.CallSubOrchestratorAsync(
    nameof(SubOrchestratorC),
    resultC);
    return resultC;
    }
    }
    

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62. @MarcDuiker 62
    https://github.com/marcduiker/durable-functions-use-cases
    

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63. @MarcDuiker
    

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64. @MarcDuiker 64
    

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65. @MarcDuiker
    

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66. @MarcDuiker 66
    Domain
    Bounded
    Context Bounded
    Context
    Bounded
    Context
    Bounded
    Context
    https://thedomaindrivendesign.io/bounded-context/
    

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67. @MarcDuiker 67
    Ecommerce
    Product
    Catalog Pricing
    Billing
    Shopping
    Basket
    https://thedomaindrivendesign.io/bounded-context/
    

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68. @MarcDuiker 68
    “Ubiquitous language identifies the terms
    and concepts within a bounded context that
    are unambiguous and agreed upon by all
    stakeholders.”
    https://thedomaindrivendesign.io/what-is-strategic-design
    

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69. @MarcDuiker 69
    Billing Shopping Basket
    https://thedomaindrivendesign.io/what-is-strategic-design
    

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70. @MarcDuiker 70
    

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71. @MarcDuiker 71
    

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72. @MarcDuiker 72
    

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73. @MarcDuiker 73
    Bounded
    Context
    Bounded
    Context
    

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74. @MarcDuiker
    

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75. @MarcDuiker 75
    “Resilience is the ability to provide and
    maintain an acceptable level of service in
    the face of faults and challenges to normal
    operation.”
    https://en.wikipedia.org/wiki/Resilience_(network)
    

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76. @MarcDuiker 76
    

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77. @MarcDuiker 77
    https://learn.microsoft.com/en-us/azure/architecture/patterns/
    

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78. @MarcDuiker 78
    

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79. @MarcDuiker 79
    

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80. @MarcDuiker 80
    Function App B
    Function App A Queue Storage
    

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81. @MarcDuiker 81
    public static class ChainingWithRetryExample
    {
    [FunctionName(nameof(ChainingWithRetryExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var resultA = await context.CallActivityWithRetryAsync(
    nameof(ActivityFunctionA),
    new RetryOptions(TimeSpan.FromSeconds(5), 3) { BackoffCoefficient = 2 },
    null);
    var resultB = await context.CallActivityAsync(
    nameof(ActivityFunctionB),
    resultA);
    var resultC = await context.CallActivityAsync(
    nameof(ActivityFunctionC),
    resultB);
    return resultC;
    }
    }
    

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82. @MarcDuiker 82
    public static class ChainingWithRetryExample
    {
    [FunctionName(nameof(ChainingWithRetryExample))]
    public static async Task RunOrchestrator(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
    {
    var resultA = await context.CallActivityWithRetryAsync(
    nameof(ActivityFunctionA),
    new RetryOptions(TimeSpan.FromSeconds(5), 3) { BackoffCoefficient = 2 },
    null);
    var resultB = await context.CallActivityAsync(
    nameof(ActivityFunctionB),
    resultA);
    var resultC = await context.CallActivityAsync(
    nameof(ActivityFunctionC),
    resultB);
    return resultC;
    }
    }
    

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83. @MarcDuiker
    

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84. @MarcDuiker 84
    Increase number of (virtual) machines Increase CPU / memory of one machine
    

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85. @MarcDuiker 85
    

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86. @MarcDuiker 86
    

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87. @MarcDuiker 87
    

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88. @MarcDuiker 88
    scale out scale out
    

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89. @MarcDuiker 89
    scale out
    scale out
    https://learn.microsoft.com/en-us/azure/azure-functions/functions-scale#scale
    Use dedicated
    resource to its
    fullest
    

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90. @MarcDuiker 90
    scale out scale out
    https://learn.microsoft.com/en-us/azure/azure-functions/functions-scale#scale
    Use higher tier / sku
    Use regular tier / sku
    

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91. @MarcDuiker 91
    App Settings:
    FUNCTIONS_WORKER_PROCESS_COUNT
    Function App resource property:
    functionAppScaleLimit
    https://learn.microsoft.com/en-us/azure/azure-functions/event-driven-scaling
    https://learn.microsoft.com/en-us/azure/azure-functions/functions-best-practices
    SCALE_CONTROLLER_LOGGING_ENABLED
    

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92. @MarcDuiker
    - Monitor your agility!
    - Ask yourself these questions before adding any code:
    - Do *I* need to write this?
    - Is this a good fit with the rest of the app?
    - What is the impact regarding resilience/scalability
    of the app?
    

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93. @MarcDuiker
    linktr.ee/marcduiker
    

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