Workshop Consul .- Service Discovery & Failure Detection
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The document discusses the use of Consul, an open-source tool by HashiCorp for service discovery and configuration management in infrastructure. It details the setup process using Docker, including creating machines, running registrators, and establishing health checks for services. Additionally, it covers the DNS integration and failure detection mechanisms within a multi-node environment.
![Check services health via API
Terminal
$ curl http://$(docker-machine ip consul):8500/v1/health/checks/http-ip ..
[
{
"Status": "passing",
"Output": "hello from 172.18.0.2",
"ServiceName": "http-ip",
},
…
]
Note that you can also check your services’s health via the
Consul API “/health” endpoint:](https://image.slidesharecdn.com/workshopconsul-170217203117/85/Workshop-Consul-Service-Discovery-Failure-Detection-28-320.jpg)
Workshop Consul .- Service Discovery & Failure Detection
- 1. www.eleven-labs.com WORKSHOP Factory Vincent Composieux @vcomposieux … to beyond and CONSULSERVICE DISCOVERY & FAILURE DETECTION
- 2. 2013 FIRST COMMIT WHAT ABOUT CONSUL? Open-source & built by HashiCorp. “Consul has multiple components, but as a whole, it is a tool for discovering and configuring services in your infrastructure.” GO WRITTEN
- 3. WHAT ABOUT CONSUL? FRONT 01 FRONT 02 FRONT 03 Terminal $ curl http://frontend.eleven-labs.com .. DNS API UP UPDOWN
- 4. WHAT ABOUT CONSUL? SERVICE DISCOVERY ➔ Register new services via configuration or API ➔ Access all available services or a specific one ➔ Updates automatically when new services are available or not FAILURE DETECTION ➔ Updates automatically Consul services when a service is down ➔ Manages services states (we can put a service in maintenance for instance)
- 5. CONSENSUS PROTOCOL http://thesecretlivesofdata.com/raft/ WHAT ABOUT CONSUL? GOSSIP PROTOCOL This is for consistency: nodes inherit from a state: follower, candidate or leader. Propagation of information (epidemy)
- 6. WHAT ABOUT CONSUL? 8600 DNS 8500 HTTP 8300 8400 RPC Use port 8300 (TCP only) but also: ➔ 8301 (TCP/UDP, Gossip over LAN) ➔ 8302 (TCP/UDP, Gossip over WAN) This port exposes: ➔ A web UI ➔ A HTTP API This port is used for DNS server. Possible to override with --dns-port
- 7. WHAT ABOUT CONSUL? https://demo.consul.io WEB UI LOOKS LIKE THIS
- 9. swarm → registrator → ekofr/http-ip swarm → registrator → ekofr/http-ip ARCHITECTURE CONSUL (Machine / Swarm Discovery) NODE #01 (Machine / Master) NODE #02 (Machine) HTTP DNS 1 2 33 DOCKER MACHINES 1 SWARM CLUSTER 7 DOCKER CONTAINERS
- 10. CONSUL > Machine Terminal $ docker-machine create -d virtualbox consul .. Create the “consul-master” machine under Docker, using the Virtualbox driver. CONSUL (Machine)
- 11. CONSUL > Container Terminal $ eval $(docker-machine env consul) $ docker run -d -p 8301:8301 -p 8302:8302 -p 8400:8400 -p 8500:8500 -p 53:8600/udp consul .. Enter your consul-master environment and run the “consul” Docker image (as server). CONSUL (Machine)
- 12. NODE #01 > Machine (New tab) Terminal $ docker-machine create -d virtualbox --swarm --swarm-master --swarm-discovery="consul://$(docker-machine ip consul):8500" --engine-opt="cluster-store=consul://$(docker-machine ip consul):8500" --engine-opt="cluster-advertise=eth1:2376" swarm-node-01 .. Create the “swarm-node-01” machine under Docker and map Swarm discovery with Consul. CONSUL (Machine) NODE #01
- 13. NODE #01 > Registrator Terminal $ eval $(docker-machine env swarm-node-01) $ docker run -d --volume=/var/run/docker.sock:/tmp/docker.sock gliderlabs/registrator -ip $(docker-machine ip swarm-node-01) consul://$(docker-machine ip consul):8500 .. Enter “swarm-node-01” machine and run a Registrator Docker image as a daemon. CONSUL (Machine) NODE #01
- 14. NODE #01 > HTTP Container Terminal $ docker network create --subnet=172.18.0.0/16 network-node-01 $ docker run -d --net network-node-01 -p 80:8080 ekofr/http-ip .. Create a “network-node-01” Docker network and run “ekofr/http-ip” using this network. CONSUL (Machine) NODE #01
- 15. NODE #02 > Machine (New tab) Terminal $ docker-machine create -d virtualbox --swarm --swarm-discovery="consul://$(docker-machine ip consul):8500" --engine-opt="cluster-store=consul://$(docker-machine ip consul):8500" --engine-opt="cluster-advertise=eth1:2376" swarm-node-02 .. Create the “swarm-node-02” machine under Docker and map Swarm discovery with Consul. CONSUL (Machine) NODE #01 NODE #02
- 16. NODE #02 > Registrator Terminal $ eval $(docker-machine env swarm-node-02) $ docker run -d --volume=/var/run/docker.sock:/tmp/docker.sock gliderlabs/registrator -ip $(docker-machine ip swarm-node-02) consul://$(docker-machine ip consul):8500 .. Enter “swarm-node-02” machine and run a Registrator Docker image as a daemon. CONSUL (Machine) NODE #01 NODE #02
- 17. NODE #02 > HTTP Container Terminal $ docker network create --subnet=172.19.0.0/16 network-node-02 $ docker run -d --net network-node-02 -p 80:8080 ekofr/http-ip .. Create a “network-node-02” Docker network and run “ekofr/http-ip” using this network. CONSUL (Machine) NODE #01 NODE #02
- 18. What’s happening on DNS? Terminal $ dig @$(docker-machine ip consul) http-ip.service.consul .. ;; QUESTION SECTION: ;http-ip.service.consul. IN A ;; ANSWER SECTION: http-ip.service.consul. 0 IN A 192.168.99.100 http-ip.service.consul. 0 IN A 192.168.99.102 Let’s make a DNS call to ensure that our “http-ip” service is available under 2 machines! Shutdown them! DNS
- 19. What’s happening on DNS? Terminal $ dig @$(docker-machine ip consul) http-ip.service.consul SRV .. ;; ANSWER SECTION: http-ip.service.consul. 0 IN SRV 1 1 80 c0a86366.addr.dc1.consul. http-ip.service.consul. 0 IN SRV 1 1 80 c0a86364.addr.dc1.consul. SRV records allows to define a priority and a weight for DNS entries but it is not supported by Consul at this time. You can find more information on SRV records on Wikipedia.
- 20. Add DNS to your system Let’s make an HTTP call to ensure that both nodes answers. Add Consul DNS server as a resolver. CONSUL (Machine)
- 21. Call HTTP service Terminal $ curl http://http-ip.service.consul hello from 172.18.0.2 $ curl http://http-ip.service.consul .. hello from 172.19.0.2 Now, perform your HTTP request and confirm that you are balanced between your two machines. HTTP DNS
- 23. NODE #01 > Add a HTTP check Terminal $ eval $(docker-machine env swarm-node-01) $ docker kill $(docker ps -q --filter='ancestor=ekofr/http-ip') .. First, kill the docker container that runs ekofr/http-ip. We will launch it just after with a health check.
- 24. NODE #01 > Add a HTTP check Terminal $ docker run -d --net network-node-01 -p 80:8080 -e SERVICE_CHECK_SCRIPT="curl -s -f http://$(docker-machine ip swarm-node-01)" -e SERVICE_CHECK_INTERVAL=5s -e SERVICE_CHECK_TIMEOUT=1s ekofr/http-ip .. Add a check to the ekofr/http-ip container. We add a HTTP check here but it could be what you want. More information about Registrator available environment variables here. More information on Consul check definition here.
- 25. NODE #02 > Add a HTTP check Terminal $ eval $(docker-machine env swarm-node-02) $ docker kill $(docker ps -q --filter='ancestor=ekofr/http-ip') .. First, kill the docker container that runs ekofr/http-ip. We will launch it just after with a health check.
- 26. NODE #02 > Add a HTTP check Terminal $ docker run -d --net network-node-02 -p 80:8080 -e SERVICE_CHECK_SCRIPT="curl -s -f http://$(docker-machine ip swarm-node-02)" -e SERVICE_CHECK_INTERVAL=5s -e SERVICE_CHECK_TIMEOUT=1s ekofr/http-ip .. Add a check to the ekofr/http-ip container. We add a HTTP check here but it could be what you want. More information about Registrator available environment variables here. More information on Consul check definition here.
- 27. Check services health via web UI If you launch the UI, you should see your health checks:
- 28. Check services health via API Terminal $ curl http://$(docker-machine ip consul):8500/v1/health/checks/http-ip .. [ { "Status": "passing", "Output": "hello from 172.18.0.2", "ServiceName": "http-ip", }, … ] Note that you can also check your services’s health via the Consul API “/health” endpoint:
- 29. THANK YOU