Consul 1.15 Practice Exam 3 — 20 Questions

Question 1

Which of these are required fields for a TCP health check definition? (Select THREE)

Accepted Answer

name. TCP checks require tcp, interval, and name fields.

Answer

timeout

Answer

http

Question 2

You are configuring a Consul Watch to trigger a script whenever a specific KV key changes. Which type of watch should you define in your configuration file?

Accepted Answer

key. The 'key' watch type is specifically designed to monitor changes to a single KV entry.

Answer

event

Answer

service

Answer

nodes

Question 3

You want to delete a key and all its children in the KV store using the CLI. Which flag should you use?

Accepted Answer

-recurse. The -recurse flag in the CLI allows the delete operation to act on the key and all nested keys.

Answer

-force

Answer

--all

Answer

--cascade

Question 4

You want to perform a blocking query on a KV key to watch for updates. Which parameter must you provide in your request based on the last observed index?

Accepted Answer

index. The index parameter is used in the query string to inform Consul that you want to wait until the current state index is greater than the provided value.

Answer

consistency

Answer

wait

Answer

timeout

Question 5

Which TWO of the following are true about the 'cas' parameter in KV writes?

Accepted Answer

It stands for Check-And-Set. The 'cas' parameter stands for Check-And-Set and requires the index to be provided to ensure atomicity.

Answer

It is only available in the CLI

Answer

It only works for new keys

Answer

It is mandatory for all writes

Question 6

You want to ensure that specific services in a remote datacenter are only accessible to certain local services. How can you achieve this?

Accepted Answer

Use Consul Intentions.. Intentions are the native Consul mechanism to control service-to-service communication, and they work across datacenters when correctly configured.

Answer

Use firewall rules on all nodes.

Answer

Modify DNS resolution.

Answer

Use ACL tokens.

Question 7

What is the function of the 'retry_join_wan' configuration?

Accepted Answer

To enable persistent WAN connections.. The 'retry_join_wan' configuration allows the agent to repeatedly attempt to join the WAN gossip pool at startup if the initial attempt fails, improving robustness.

Answer

To sync secondary data.

Answer

To force a specific leader.

Answer

To rotate the encryption key.

Question 8

When providing a session TTL, what is the minimum duration allowed?

Accepted Answer

10 seconds. The minimum session TTL allowed is 10 seconds.

Answer

30 seconds

Answer

5 seconds

Answer

1 second

Question 9

Which TWO of the following are true regarding Consul KV watches?

Accepted Answer

Watches use blocking queries internally. Watches can be configured via agent configuration or the API, and they use blocking queries internally.

Answer

Watches can only monitor keys that exist

Answer

Watches automatically restart after a script failure

Answer

Watches are only available in the Enterprise edition

Question 10

When configuring ACL replication, where must the 'acl_replication_token' be defined?

Accepted Answer

In the secondary datacenter's server agents.. The replication token is configured on the secondary datacenter's Consul servers to allow them to read from the primary.

Answer

In the primary datacenter's client agents.

Answer

In the Consul Enterprise license file.

Answer

On all nodes in both datacenters.

Question 11

Which protocol do Consul servers use to maintain the WAN gossip pool?

Accepted Answer

Serf (SWIM). Consul uses the Serf library, which implements the SWIM-based gossip protocol for both LAN and WAN communication.

Answer

gRPC

Answer

DNS

Answer

HTTP

Question 12

When joining a new datacenter to an existing WAN pool, what is the best practice for server versions?

Accepted Answer

Versions should be consistent across all datacenters.. Running different versions of Consul is supported during upgrades, but maintaining consistent versions across the federation is recommended for stability.

Answer

The new DC must run a newer version.

Answer

The new DC must run an older version.

Answer

Version doesn't matter at all.

Question 13

Which Consul agent configuration parameter defines the KV store file location when running locally?

Accepted Answer

data_dir. While the KV store is in-memory, its persistence (if snapshots are used) is managed by the data_dir.

Answer

server_dir

Answer

kv_dir

Answer

state_dir

Question 14

You want to perform a list operation on a KV prefix to see all keys, but you don't want the values returned. Which API parameter helps reduce payload size?

Accepted Answer

keys=true. The 'keys' parameter can be used with a prefix to return only the list of key names, not their contents.

Answer

raw=true

Answer

list=true

Answer

summarize=true

Question 15

Which TWO of the following are true regarding the behavior of the Consul KV store?

Accepted Answer

Stale reads allow for reading from non-leader nodes. KV values are stored as base64 encoded strings in the API, and they are eventually consistent for stale reads.

Answer

Keys can only contain alphanumeric characters

Answer

All KV writes are synchronous across all nodes

Answer

The KV store is limited to 1GB of data

Question 16

You have enabled ACL replication between a primary and secondary datacenter. What is the effect of changing an ACL policy in the primary datacenter?

Accepted Answer

The changes are asynchronously replicated to all secondary datacenters.. ACL replication automatically propagates changes from the primary to secondary datacenters to maintain consistency.

Answer

The changes only propagate if the secondary is in maintenance mode.

Answer

The changes require a manual trigger on secondary servers.

Answer

The changes are ignored by secondary datacenters.

Question 17

Which TWO of the following are common use cases for the Consul KV store?

Accepted Answer

Distributed locking. KV is primarily used for configuration management and distributed locking.

Answer

Traffic routing

Answer

Service discovery

Answer

Running custom scripts

Question 18

Which TWO statements are true regarding Consul Mesh Gateways?

Accepted Answer

They are required when direct WAN gossip is not possible between datacenters.. Mesh gateways function at Layer 7 and are essential for connectivity between isolated datacenters.

Answer

They replace the need for Consul servers in the secondary datacenter.

Answer

They increase the latency of LAN gossip.

Answer

They require a separate Consul Enterprise license.

Question 19

Which TWO of the following are valid ways to troubleshoot inter-datacenter communication issues?

Accepted Answer

Inspect server logs for RPC errors between datacenters.. Verifying WAN gossip members and checking server logs for RPC errors are standard troubleshooting steps.

Answer

Change the datacenter name in the config.

Answer

Restart all clients in the datacenter.

Answer

Use 'consul kv export' to sync data.

Question 20

Which THREE of the following are true about Consul KV keys?

Accepted Answer

Keys support storing binary data. Keys are organized in a hierarchy, they are case-sensitive, and they can store arbitrary data.

Answer

Keys must start with a slash

Answer

Keys cannot contain spaces