going reactive in the land of no
TRANSCRIPT
Going Reactive in the Land of NoSean Walsh | Field CTO
(@SeanWalshEsq)
reactivemanifesto.org
Reactive: the architecture for modern, scalable applications
Forces
• Exploding user bases
• Cheaper and more available hardware
• IoT
• Science
Something was standing between my large health and wellness client and their customers. That something was about to put them out of business.
A Monolith• Expensive to maintain, lack of in-house capability due to
repeated outsourcing
• Non distributed
• Dependency on a custom and very expensive Oracle installation
• Ops heavy rather than developer heavy
• Effectively…
A Big Ball of Mud
Late 2014 - A false start•Not “all in”•Large team engaged anyway•Missing real requirements
churn…
Early 2015
Let’s start over but this time we do it wrong different, we do it my way! - That One Guy
Same leadership
churn churn churn…
Sr Director No
Spring Boot
Groovy Gpars Actors
Gradle
SBT
MavenJava
Scala
Akka
AnsibleGroovy
Department of Redundancy Departmentpopulation Sean and Nicholas
a final attempt at purity - one sprint to prove it
Finally the Light• Full company engagement (even Oprah!)• New, modern CTO working in close partnership with my team
and others• Real requirements and mandatory Ops support• Good news and bad news
No No Noooo• Still risk adverse, CQRS and Event Sourcing sounded scary
so NO• Ops was now devops and guess that their favorite word
was?• NO clustering, NO Cassandra, NO Kafka
• And then were three - Sayre joins the team• They let us use Play/Akka/Cassandra• We had customers!• Core software was all rebuilt from the ground up
Accomplishments• Unheard of velocity in “core” - Play - simplicity• Core fully production ready by November of 2015• 12 microservices - billion+ transactions per day capable• Modern aggregated monitoring and logging provided
incredibly quick root cause analysis• Never before seen resilience and application stability
A Bit too much Compromise• Stateless applications easier to reason about at first but
cost plenty in the long run• Perceived investment and value in Cassandra• Final waterfall caused some costly non-DDD design• Devops spaghetti in the form of Ansible scripts• Poor mans CQRS and Event Sourcing• And oh man no Kafka and now look…
THIS
What we really needed
Other Lessons Learned• Legacy, immature mobile, other contaminating feeds• Continuous delivery and deployment but tricky due to
service coupling• Migration not as an afterthought• Oh and don’t ever give a developer both a load test
script and access to production
Strive for Yes• Don’t roll your own• Need for clustered middleware• More emphasis on application tier• Need for durable pub/sub• Simpler devops abstractions - orchestration - dcos• Less code invasive monitoring• Fast data pipeline for anti-corruption
1) The company is now on the same playing field as the disruptors
2) What was a monolith, now a platform for creative new product ideas
3) Thanks to the above and a famous 40 Lb weight loss the stock is starting to rebound
