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CloudConf2017 - Deploy, Scale & Coordinate a microservice oriented application
The document discusses deploying, scaling, and coordinating microservices using Docker and a distributed locking system. It outlines the use of DNS for service coordination, how to report application status through health checks, and the integration of various coordination systems like etcd and Redis. Additionally, the document explains how to manage service configurations and locks effectively in a distributed system.
CloudConf2017 - Deploy, Scale & Coordinate a microservice oriented application
- 1. CloudConf Turin 16th March2017 Deploy, scale and coordinate a microservice oriented application cloudconf.it
- 2. Walter Dal Mut walter.dalmut@ corley.it Solution Architect @ Corley
- 3.
- 4. They're coming outtathe walls
- 5.
- 6. Issue a newprocess (deploy) $ docker service create --name app registry.walterdalmut.com/app:v1 $ ./app &
- 7. Run different processes(scale) $ docker service scale app=10 $ ./app & $ ./app & $ ./app &
- 8. What about thelocking system? In a distributed system: locks (distributed locks) are the foundations for activity synchronization
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- 10. A service haveits own con guration at launch I am here with this address, port etc... A service require other service con gurations Where the database is, which password i should use, etc... The service should reports its owns status I am alive and responsive (for healthcheck) other services can check the health report for the maintenance mode or to shortcircuit the service dependency
- 11. To expose thecoordination problem we create an application
- 12. Read the twitterstream #cloudconf2017
- 13. users that tweetwith this handle create a reserved API service [ JSON over HTTP ] GET /tweet - list my tweets POST /tweet - record a new tweet The database to store tweets is self-contained in the API service
- 14. Now every serviceis exposed with a unique pair address:port in the swarm
- 15. every box isa container (service) blinks for activities (publish new tweets)
- 16. Multiple services (1) (1) (1..*) (n) (1..*) Stream readerer Distributedqueue Service Worker (need a distributed lock) a lock identi es the service deployment progress on missing => service deploy on existing => publish messages Per user container A proxy to list users and redirects requests
- 17. HTTP framework > GET/user/walterdalmut HTTP/1.1 > Host: cluster.corsi.walterdalmut.com:30000 > User-Agent: curl/7.47.0 > Accept: */* < HTTP/1.1 302 Found < location: http://cluster.corsi.walterdalmut.com:30002/v1/tweet < vary: origin < cache-control: no-cache < content-length: 0 < Date: Sun, 12 Mar 2017 11:26:50 GMT < Connection: keep-alive
- 18.
- 21. Every user haveits own network address and port Every user expose its own API How do we connect services together?
- 22. DNS as acoordination system DNS is a good solution to point things in a network DNS SRV expose a service address con guration $ dig srv _auth._tcp.walterdalmut.com +short 1 10 8080 1.api.walterdalmut.com 1 10 8080 2.api.walterdalmut.com
- 23. And service congurations? host: db.mynet.local port: 3306 username: root password: root dbname: example
- 24. K / V Severalcoordination systems available Etcd is one of the most interesting coordination system available Consul integrates di erent things together like: DNS, KV, etc... many other: zookeeper, etc...
- 25. Redis as acoordination service
- 26. distribute con gurationsat paths $ cat mydb.conf | redis-cli set /path/to/disk/mydb.conf -
- 27. Where is my`ls` command now? $ redis-cli keys /path/* 1) "/path/to/disk/mydb.conf"
- 28. Get my conguration back $ redis-cli get /path/to/disk/mydb.conf host: db.mynet.local port: 3306 username: root password: root dbname: example
- 29. How to reportthe application status? Healthchecks
- 30. Con gurations canalso expires Dead man switch application reports continuously cat mydb.conf | SETEX /path/to/disk/mydb.conf 30 - EXPIRE /path/to/disk/mydb.conf 30 ... sleep 20 EXPIRE /path/to/disk/mydb.conf 30 ...
- 31. Services links together Cani watch for con guration changes? refresh my services on updates
- 32. Redis Keyspace Notications or in your con guration le CONFIG SET notify-keyspace-events AKE
- 33. Listen for mycon guration changes SUBSCRIBE __keyspace@0__:/path/to/disk/mydb.conf
- 34. Here the event $cat mydb.conf | redis-cli set /path/to/disk/mydb.conf - 1) "message" 2) "__keyspace@0__:/path/to/disk/mydb.conf" 3) "set"
- 35. Distributed locks In asingle node for redis NX - if not exists PX 30000 - expires in 30000 ms SET /etc/lock/username/.lock {random_value} NX PX 30000
- 36. After 30 secondsthe lock expires SET /etc/lock/walterdalmut/.lock 3891573 NX PX 30000 OK SET /etc/lock/walterdalmut/.lock 2857152 NX PX 30000 (nil)
- 37. How do irelease the lock? DEL /etc/lock/walterdalmut/.lock
- 38. How do iextend the lock? EXPIRE /etc/lock/walterdalmut/.lock 30
- 39. How do iwatch for lock release? Lock releases SUBSCRIBE __keyspace@0__:/etc/lock/walterdalmut/.lock 1) "message" 2) "__keyspace@0__:/etc/lock/walterdalmut/.lock" 3) "del" 1) "message" 2) "__keyspace@0__:/etc/lock/walterdalmut/.lock" 3) "expired"
- 40. Thank you forlistening