Github user mfenes commented on the issue:
https://github.com/apache/zookeeper/pull/451
Re-resolving at StaticHostProvider level may not be sufficient as
InetAddress.getAllByName(String host) itself uses a Java-level cache inside
InetAddress and turns to name service (e.g. DNS) only if the host could not be
found in the Java-level cache.
Unfortunately, when Java resolves a new host using the name service, it
puts the host and its addresses in the cache with TTL cache FOREVER.
This means, once a host gets resolved by Java, it will never again turn to
the name service to re-resolve it. If a host's addresses get updated in DNS,
the address cache in Java will still contain the old entry forever.
So re-resolving at StaticHostProvider won't help in this case, as
InetAddress.getAllByName(String host) will still return the old address(es) I
think.
Check the getCachedAddresses method inside InetAddress, the get() method of
static final class Cache inside InetAddress and
sun.net.InetAddressCachePolicy.get() which returns cachePolicy with default
value -1 (FOREVER) if it is not overridden by Security properties
"networkaddress.cache.ttl" and "networkaddress.cache.negative.ttl".
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