dns: New resolver backend "miekgdns2" with reliability improvements #660
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Create a new version of the `dns/miekgdns` package with changes to improve the reliability of queries since they are typically used for service discovery. The notable changes: * Search domains are not supported. We don't use them, when they are used they put more load on DNS servers, and they make the behavior of resolution harder to understand. * Always use TCP for queries, don't start with UDP. We're using DNS for service discovery and the result size is usually large enough that TCP must be used anyway. Instead of starting with UDP and needing to wait N seconds to know if the packet was dropped - just start with TCP. * Pool connections to DNS servers. Instead of creating new UDP and TCP sockets for every query, we keep TCP connections to DNS servers open and reuse them if possible. * Use the "attempts" option from /etc/resolv.conf. Instead of failing the query immediately due to network issues, we retry based on the "attempts" setting which is 2 by default. This change also makes the resolver backend used by the Memcached client configurable so that we can test the new backend before making it the default implementation. Signed-off-by: Nick Pillitteri <[email protected]>
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What this PR does:
Create a new version of the
dns/miekgdnspackage with changes to improve the reliability of queries since they are typically used for service discovery.The notable changes:
This change also makes the resolver backend used by the Memcached client configurable so that we can test the new backend before making it the default implementation.
Which issue(s) this PR fixes:
N/A
Checklist
CHANGELOG.mdupdated - the order of entries should be[CHANGE],[FEATURE],[ENHANCEMENT],[BUGFIX]