Consul 1.15 Practice Test 6 — 10 Questions

Question 1

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 2

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 3

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 4

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 5

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 6

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 7

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 8

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 9

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 10

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