Register a Service with Consul Service Discovery

Question 1

One of the major use cases for Consul is service discovery. Consul provides a _ that downstream services can use to _ of their upstream dependencies.

Answer 1

DNS interface

find the IP addresses

Question 2

Consul knows where these services are located because _.

Answer 2

each service registers with its local Consul client

Question 3

You can register services either _, which is the most common way to register services, or by making _.

Answer 3

by providing a service definition

a call to the HTTP API

Question 4

Consul loads all configuration files in the _, so a common convention on Unix systems is to name the directory something like

Answer 4

configuration directory

/etc/consul.d

Question 5

Consul can register services that _. It correlates each running service with its registration based on the service’s port.

Answer 5

aren’t running yet

Question 6

If you wanted to register multiple services, you could create multiple _ in the Consul _.

Answer 6

service definition files

configuration directory

Question 7

Once the agent adds the service to Consul’s service catalog you can query it using either the _ or _.

Answer 7

DNS interface

HTTP API

Question 8

The DNS name for a service registered with Consul is _ , whereNAMEis _

Answer 8

NAME.service.consul

the name you used to register the service

Question 9

The fully-qualified domain name of the web service isweb.service.consul. Query the DNS interface (which Consul runs by default on port8600) for the registered service.

Answer 9

dig @127.0.0.1 -p 8600 web.service.consul

Question 10

Filter your HTTP API query to look for only healthy instances.

Answer 10

curl ‘http://localhost:8500/v1/health/service/web?passing

Question 11

You can update service definitions without any downtime by changing _ and sending a_to the agent or running_.

Answer 11

the service definition file
SIGHUP
consul reload

Question 12

The ‘check’ stanza of this service definition adds a _ that tries to _ every _.

Answer 12

script-based health check
connect to the web service
10 seconds via curl

Question 13

If the command exits with an exit code >= 2, then the check will _. An exit code of 1 will be considered as _

Answer 13

fail and Consul will consider the service unhealthy

warning state.

Question 14

Now reload Consul’s configuration to make it aware of the new health check.

Answer 14

consul reload

Question 15

Consul’s DNS server only returns _

Answer 15

healthy results.