Fission: a FaaS for Kubernetes @ SCALE16x

Slides for the Fission.io talk at So-Cal Linux Expo, March 2018.

Transcript

1. Functions as a Service for Kubernetes Soam Vasani, Platform9 Systems
2. Starting out with Kubernetes is too hard • Before you can run your program: • build a container image, push it to a registry • write a Deployment specification with a Pod specification in it • write a Service • create an Ingress (hopefully you have an ingress controller set up) • Rebuild container image on changes
3. Runtime resource usage • Rarely-used services still use a minimum amount of resources • Cluster capacity: Number of deployments vs amount of usage • Services should be nearly free when idle
4. What if? • We had the power of containers and Kubernetes, but with lightweight dev workflows? • We could have cluster capacity that’s proportional to actual usage?
5. What if? • We had the power of containers and Kubernetes, but with lightweight dev workflows? • We could have cluster capacity that’s proportional to actual usage? Functions as a Service!
6. Scaling up from zero • Services should be ~free when idle • Services should be fast when needed • These two goals require fast “cold starts”
7. Fission: a FaaS for Kubernetes • Short-lived stateless “functions” • Defined declaratively at the source-level • Functions free when idle: Started quickly on-demand
8. Fission concepts • Functions • Environments • Triggers
12. HTTP, NATS, Kafka, Azure Storage Queues, Kubernetes Watches, Timers, … NodeJS, Python, Go, Ruby, C#, PHP, Bash(!), Perl
13. Fission: how it works • Function Storage • Executor: Put functions into pods and run them • HTTP Router • Other Trigger Implementations
14. Function Executors • Pool-based executor: low-latency, small idle overhead • “Pre-warmed” pool of environment containers • Functions loaded into containers on-demand • New-deployment executor: high latency, no idle overhead
26. Demo • Hello world
27. Application Config Management • Action-based CLIs great for starting out • But they make it hard to repro on another cluster, keep track of changes, do idempotent deploys, etc.
28. Declarative App Specs • Declarative specifications great for source control, updating existing apps, and idempotent behavior • But they’re not great for new users • There’s too much YAML to write from scratch
29. Config by Example • “Save what I’m doing on this cluster so I can do it on another cluster” • Generate declarative specs, check them into source control with your app • No writing new YAMLs!!
30. Demos • Creating Specs without writing YAML • Continuous testing • Declaratively building source code
31. Scaling Functions at Runtime • Fission gives you some control over runtime properties • Autoscaling: Min, max instances • Min Instances: Idle cost vs. Burst tolerance • Max Instances: Throughput vs Cost
32. Demo • Scaling functions up manually with minScale > 0
33. Function Composition • Function Composition: creating complex functions out of simpler, smaller functions
34. Function Composition • Lots of ways to do it! • Just make the function bigger • Call other functions over HTTP • Pipe function in/out over a Message Queue (NATS, Kafka etc)
35. Function Composition • Simple approaches work for a few functions • None of these have a holistic view of the system • How do we deal with inter-function compatibility? • How do we do incremental upgrades?
36. Fission Workflows • Create a “flowchart” of functions • No explicit HTTP or RPC calls • Fission Workflows co-ordinates data and control flow • Workflows are lightweight, extensible, fault-tolerant
37. Fission Workflows Internals • Event-sourcing using NATS-streaming • Tolerate restarts of any nodes/pods; restarts the workflow from the right place • Write workflows in a simple YAML (more languages coming)
38. Demos • Hello world • Automatic parallelization
39. Status and Roadmap • Fission in late alpha/early beta • 1.0 Coming Soon • Fission-Workflows beta late 2018 • Stability, security, performance
40. Roadmap • More triggers integrations: Events from various AWS, Google, Azure cloud services • Better Operational experience: • Istio, Prometheus, overall observability of the system • Lots of progress on Fission Workflows
41. Thanks! fission.io github.com/fission/fission github.com/fission/fission-workflows Slack: slack.fission.io Twitter: @fissionio