Docker Service Discovery & Composition

Day of Docker 2015 Oslo Conference

Transcript

1. Service Discovery & Composition DoD - Oslo - 2015 Jonathan Camp git clone https://github.com/kung-foo/dod-workshop cd dod-workshop && ./workshop-init.sh
2. About Me • 5 years at Blue Coat Norway AS (formerly Norman) • 10 years at Lawrence Livermore National Laboratory (U.S. Department of Energy) • Jeg snakker litt norsk, men du ikke vil at jeg skal! • Architect for Blue Coat’s Malware Analysis Appliance git clone https://github.com/kung-foo/dod-workshop cd dod-workshop && ./workshop-init.sh http://keybase.io/kung_foo 8F1F B151 D565 3923 @irondojo
3. Goals 1. Why do we need service discovery? 2. Is discovery sufficient? 3. DIY or “batteries included”?
4. Workshop Format and Requirements • Code > PowerPoint • Interactive: Show. Discuss. Share. • Four hands-on demos Who wants to be my OS X guru? • Docker ◦ 1.9+ if you want to try the newest network stuff • docker-compose
5. Motivation docker run node.js; # woot! now what?
6. Example #1 nginx node.js postgres
7. nginx.conf upstream backend { server node:8080; } server { listen 80 default_server; }
8. Example #2 nginx node.js postgres node.js
9. nginx.conf upstream backend { server node-1:8080; server node-2:8080; } server { listen 80 default_server; }
10. Example #3 nginx node.js postgres node.js node.js Docker Host 1 Docker Host 2
11. nginx.conf upstream backend { server node-1:8080; server node-2:8080; server ???:8080; # weave address? } server { listen 80 default_server; }
12. Questions • What happens when a service container dies? • Can we dynamically add and remove node.js containers? • How do we avoid hard-coding location/ports? • Why are all Docker examples based on nginx + node.js?
13. Bootstrapping the Workshop git clone https://github.com/kung-foo/dod-workshop cd dod-workshop && ./workshop-init.sh Notes: 1. If you are using boot2docker, please allocate more than one CPU 2. Did you miss a step? Take a look at dod-workshop/demo-*/SCRIPT.md
14. Workshop Roadmap Demo #1 Python app + redis Demo #2 += consul += service registry Demo #3 += service health Demo #4 -= Python += golang += consul template += redis slaves += scaling += benchmarks
15. Demo 01 1. Goals a. Make sure everyone’s env is ready to go b. Use docker-compose c. Understand: docker run --link d. Scale redis container by one e. Scale web container by one 2. Caveat for 1.9 Show me the code!
16. Demo 01 app.py redis links to
17. New in Docker 1.9 Remember when I said that /etc/hosts was static?
18. Demo 02 1. Goals a. find a better source of current containers and services 2. New a. gliderlabs/registrator b. consul (will introduce fully in next demo) 3. Notes a. we could just use the docker API, why not? The Registrator
19. Demo 02 app.py redis consul kv registrator Docker Daemon
20. gliderlabs/registrator • A service registry populated from the Docker API • Data is stored various backends: Consul, etcd, SkyDNS 2 • Requires a Docker daemon volume mount • Sponsored by DigitalOcean and Weaveworks
21. Consul Key/Value Store • We’ll cover more Consul details in demo-03 • Distributed RESTful KV store
22. Where are we so far? Links? Very limited, static, and messy. /etc/hosts? Limited, getting better with Docker 1.9 Docker API? Requires access to the Docker daemon. Registrator? Simple, fast, combined with Consul can provide health checks. Can we do better?
23. Demo 03 1. Goals a. service health checks if you are going to discover services, you should also do health checks 2. New a. consul i. service defs ii. health checks b. consul-ui
24. Demo 03 redis consul consul ui
25. Consul Part 2 • Agent based distributed cluster management ◦ DNS ◦ Service Definitions ◦ Health Checks ◦ Key/Value Store • Based on Serf ◦ Based on MemberList ▪ Gossip protocol implemented using SWIM
26. Consul Service { "service": { "name": "redis", "tags": ["slave"], "port": 6379, "checks": [{ "script": "redis-check", // * "interval": "5s" }] } } /demo-04-full/slave/root/etc/consul.d/redis.json see: redis-check
27. Demo 04 1. Goals: a. fully working scalable cluster with health checking b. customize a health check 2. New: a. consul-template b. rrproxy c. Apache Bench
28. Demo 04 rrproxy redis-master consul consul ui redis-slave redis-slave
29. Consul Template Master = "redis-master" # note link Slaves = [ {{ range service "redis" }} {{ if .Tags | contains "slave" }} "{{ .Address }}", {{ end }} {{ end }} ] /* /^(o.o)^\ /^(o.o)^\ /^(o.o)^\ */ Master = "redis-master" Slaves = [ "192.168.200.4", "192.168.200.7", "192.168.200.8", ] • Rewrites config files based on changes in Consul’s registry • Based on golang syntax • TIL: parseJSON
30. rrproxy • Simple reverse proxy • GET /db/{key-name} returns value from random redis-slave • POST /db/{key-name} sets value in redis-master • configuration read from a TOML file
31. Used But Not Covered • Alpine Linux ◦ http://www.alpinelinux.org/ • s6-overlay ◦ https://github.com/just-containers/s6-overlay
32. Wrap Up • Nothing worked? • Next steps: ◦ Cluster scheduling (i.e. Kubernetes, Nomad, AWS ECS) ◦ Networking (i.e. Weave, ZeroTier)
33. Questions?
34. Thanks!