This document discusses using Varnish in a microservices architecture. It notes that microservices increase development velocity but can massively increase the number of HTTP calls. Varnish can help by centralizing caching and invalidation, allowing stateless microservices and adding resiliency and monitoring. The document recommends modifying Varnish configuration language (VCL) to add parent IDs to cached responses to help with profiling microservices.

1. Varnish Software
Marius Magureanu
software developer
marius@varni-sh.com

2. Microservice
instrumentation with
Varnish

3. Life after APIs…
How about
Microservices?

4. Microservices (1/2)
• Application pattern used for the last couple
of years
• Reduces complexity by having small (micro)
services that are relatively simple
• Distributed application

5. Microservices (2/2)
• Increase development velocity
• Problem: Massive increase in the number of
HTTP calls

6. zoo
baz
bar
foo
service
directory

7. Varnish in a
microservice
architecture

8. quu
zoo
baz
bar
foo
varnish

9. Gains
• Centralise caching and invalidation
• Allows for stateless micro-services
• Add resiliency and monitoring

10. Profiling micro-services
is hard

11. title_lu
page_comp
artd autho
corr
30ms
10ms
55ms
40m
s
98ms

12. Changes needed
• Add the parent ID of call to the response
• Any annotations that should be added as
well
• ModifyVCL to add parent ID of cached
responses

13. GET /baz HTTP/1.1
Host: api.acme.com
Apikey:
Trace-id: 6382
Span: 6731
Parent-Span: 6636
3e707fd1d239b3978d45

15. https://github.com/varnish/zipnish

16. Thanks