[filebeat] introduce dnsConfig values for the containers

[orong-pp]

Signed-off-by: Oron Gola oron.gola@perception-point.io

• Chart version not bumped (the versions are all bumped and released at the same time)
• README.md updated with any new values or changes
• Updated template tests in ${CHART}/tests/*.py
• Updated integration tests in ${CHART}/examples/*/test/goss.yaml

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[cla-checker-service]

💚 CLA has been signed

[orong-pp]

cla/check

[orong-pp]

hi
@jmlrt @Crazybus please review

[orong-pp]

some details:

the issue:
when kubernetes runs a dns query in one of its pods, it first tries to look for the record in its internal namespaces. it can take 4-5 queries that search different options before we actually get to the final answer
in case we query an external website like spot.io we get 4-5 times more queries than we actually need and this puts unwanted load on coredns pods.

the details for this are all explained here
https://dev.to/mrkaran/dns-lookups-in-kubernetes-5cm1

solution:
so to deal with this issue one can define the ndots dns configuration option
the default is 5 and it means that only urls with 5 or more dots (.) in it will be queried directly from external dns and not go through 4 redundant dns queries

to set the ndots config option lower I added this pull request and made it possible to control this value and set it lower, so that all queries are direct and no internal search is made

dnsConfig documentation:
this is how dnsConfig should be configured according to kubernetes docs
https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/

[orong-pp]

I have now signed the CLA

[jmlrt]

jenkins test this please

[botelastic]

This PR has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions. To track this PR (even if closed), please open a corresponding issue if one does not already exist.

[jmlrt]

jenkins test this please

[jmlrt]

LGTM⛴, just a suggestion about adding a commented example in values.yaml.

[orong-pp]

jenkins test this please

[orong-pp]

@jmlrt @Crazybus please review

[jmlrt]

LGTM⛴

[jmlrt]

jenkins test this please

[jmlrt]

backported to 6.8, 7.9 and 7.x branches