dealing with legacy - the cloud native journey, part 2
TRANSCRIPT
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Ensuring Cloud Native Success: The Legacy Journey Dec. 2015
Slides: http://cote.io/legacy-cloud-native/
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The three “journeys”
Greenfield
• Brand new• Little integration with
existing IT• Rarely “mission critical”
Legacy
• Makes all the money• Fragile, change is high
risk• Can consume all
corporate attention
Transformation
• Targets entire organization
• Benefits of scale• “Culture” change drives
success
See Recording Dec 1st
, 12 central Dec 15th, 12 central
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@cote – Director, Technical Marketing at Pivotal for Pivotal Cloud Foundry
Former industry analyst at 451 Research and RedMonk
Corporate Strategy & M&A at Dell Software developer Podcasts: cote.io/podcasts FierceDevOps columnist More: http://cote.io or
Hello!
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Why?
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The goal is not “cloud,” rather shifting to using software as your core enabler of business
Release weekly, if not daily
Software continually updated to match evolving
business models
IT is the enabler of growth
Software Defined BusinessFor the business “oh crap” motivations, see “The 3 Horsemen of the Digital Apocalypse” and the first part of of my DevOpsDays talk.
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Legacy
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“Legacy” is usually existing software that’s odious to change
“Makes all the money” so it’s mission critical
Lacks good testing, so it’s risky to change, fragile
Often built with “pre-cloud” technologies
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Actively manage your portfolio or it will manage you
Source: “A Value Framework that Works for Transforming Your Application Portfolio,” June, 2015. See more commentary on dealing with legacy in “Dealing With The Stuff That Makes All The Money.”
Key transformation effects:
• Reduce costs to run “legacy” systems
• Free resources (time, money, attention) for “innovation”
• Waste elimination: cloud platform automates infrastructure management & “paperwork”
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Filter projects Projects with low business value
– make it worth your time The business case hasn’t run out
yet – don’t write things off Agile Resistant Projects:
1. Tight integration and coordination across division lines
2. Company-wide and/or industry standards can not easily be changed or ignore
3. Technology ill-suited for cloud native, or not “modernized” at all
See “Migrating the Monolith,” Rohit Kelapure, Nov 2015 for more technical details.
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Approaches for the left-overs Virtualize to control costs
and maximize management
API gateways combined with the strangler pattern
Rewriting to be cloud native
See “Migrating the Monolith,” Rohit Kelapure, Nov 2015 for more technical details.
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Filtering for technology fit
Generally good: Stateless Horizontal scaling Well packaged Java
applications Applications that are
configured at runtime RESTful services approach
Generally bad: Reliance on local storage Manages complex background
processes Uses proprietary APIs,
hardware Manual startup/shutdown Long lived, fast connections
Sources: "Pivotal Cloud Foundry Application Migration Selection Criteria," Josh Kruck & Abby Kearns, Q1 2015; "How Do I Migrate Applications to Pivotal Cloud Foundry?" Josh Kruck, June 2015; “Case Study: Refactoring A Monolith Into A Cloud Native App” series, Jared Gordon, Aug 2015.
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Get strict with testing
The Legacy Code DilemmaWhen we change code, we should have tests in place. To put tests in place, we often have to change code.
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Strangle old code, perhaps replacing…one day
Sources: pattern write-up from Martin Fowler, small case studies. Picture from wikipedia’s Ficus aurea page, diagram from Branch by Abstraction write-up, 2011.
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Review boards and other “helpful” processes Automate the helpful processes Establish trust with review
boards – small wins, etc. Expose process bottlenecks
Your process is as important as the process, change it accordingly
Sources: clip art from geralt.
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If all this sounds hard, let that be a reminder of how important architectural and process hygiene is – start doing it right!
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What’s next?
Greenfield
• Brand new• Little integration with
existing IT• Rarely “mission critical”
Legacy
• Makes all the money• Fragile, change is high
risk• Can consume all
corporate attention
Transformation
• Targets entire organization
• Benefits of scale• “Culture” change drives
success
See Recording Dec 1st
, 12 central Dec 15th, 12 central
