The Consul Agent

Question 1

In production you would run each Consul agent in either in _ or _ mode

Answer 1

server

client

Question 2

Each Consul datacenter must have at least one _, which is responsible for maintaining Consul’s state.

Answer 2

server

Question 3

Consul’s state includes information about _, _, _

Answer 3

other Consul servers and clients
what services are available for discovery
and which services are allowed to talk to which other services.

Question 4

In order to make sure that Consul’s state is preserved even if a server fails, you should always _

Answer 4

run either three or five servers in production.

Question 5

The __ number of servers (and no more than _ of them) strikes a balance between _ and _.

Answer 5

odd
five
performance
failure tolerance

Question 6

A client is a lightweight process that _ (1) (2) (3).

Answer 6

registers services, runs health checks, and forwards queries to servers

Question 7

A client must be running on every _ in the Consul datacenter that runs services, since clients are the source of truth about _

Answer 7

node

service health

Question 8

Consul uses your _ as the default node name. If your _ contains _ DNS queries to that node will not work with Consul. To avoid this, explicitly set the name of your node with the_flag.

Answer 8

hostname
hostname
periods,
-node

Question 9

Check the membership of the Consul datacenter by running the_ command in a new terminal window. You can discover additional metadata by providing the_ flag.

Answer 9

consul members

-detailed

Question 10

The_command runs against the Consul client, which gets its information viagossip protocol. The information that the client has is eventually consistent, but at any point in time its view of the world may not exactly match the state on the servers.For a strongly consistent view of the world, _, which forwards the request to the Consul servers.

Answer 10

members

query theHTTP API,

Question 11

Stop the Consul agent by using the_ command. This will gracefully stop the agent, causing it to leave the Consul datacenter and shut down

Answer 11

consul leave

Question 12

When you issue theleavecommand, _ datacenter. When an agent leaves, its local services running on the same node and their checks are _ and Consul doesn’t try to _

Answer 12

Consul notifies other members that the agent left the
removed from the catalog
contact that node again

Question 13

Forcibly killing the agent process indicates to other agents in the Consul datacenter that _. When _, its health is marked _, but it is not _. Consul will automatically try to _, assuming that it may be unavailable because of _, and that it may be coming back.

Answer 13

the node failed instead of left
	a node fails
	as critical
	removed from the catalog
	reconnect to a failed node
	a network partition

Question 14

If an agent is operating as a server, a graceful leave is important to _. Check theAdding and Removing Servers tutorialfor details on how to safely add and remove servers.

Answer 14

avoid causing a potential availability outage affecting the consensus protocol