A client's /etc/chrony.conf contains the line `pool 2.pool.ntp.org iburst maxsources 4`. Which TWO statements about that line are correct? (Choose two.)
LPIC-1 Exam 102-500, objective 108. Essential system services medium
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The options
Choose 2.
Correct The name is expected to resolve to several addresses, and chronyd uses a number of them as independent time sources.
Correct. That is the point of the pool directive: one hostname, several servers, so the loss of any single volunteer server does not leave the host unsynchronised.
Correct maxsources caps how many sources chronyd takes from this pool, here at four.
Correct. maxsources is an option of the pool directive limiting the number of addresses actually used, whatever the name resolves to.
Not correct pool is only a spelling variant of server, so the line yields exactly one time source.
Wrong. server names a single NTP server and creates one source. pool is a distinct directive precisely because it expands to several.
Not correct iburst delays the first request by a random interval so that clients do not hit the pool simultaneously.
Wrong, and close to the inverse. iburst sends a rapid burst of requests at start-up so the first measurement arrives within seconds rather than after several normal poll intervals.
Not correct The line configures chronyd to serve time to clients in the 2.pool.ntp.org zone.
Wrong. Serving time to others is configured with allow (and optionally local); pool and server describe where this host gets time from.
Why
The distinction to carry away is that server binds one source, pool binds many from one name, and both accept the same per-source options such as iburst and minpoll. The numbered prefixes 0. through 3. of pool.ntp.org exist so that a host can list several pool lines and be given different sets of servers. In /etc/ntp.conf the reference implementation offers the same pair of directives with the same meaning.
Where this comes from
- Cited
- manual page chrony.conf(5)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 108 and space the ones you get wrong.
More questions on this objective
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