[Backport release-1.6] fix(opensearch-operator): align DNS_BASE with the platform cluster domain - #5072

…main

The operator reads DNS_BASE and builds every in-cluster name it needs
from it: the securityconfig job target, its own OpenSearch API client
URL, the Dashboards host, and the SANs it writes into node
certificates. The vendored chart defaults that to cluster.local, so on
a cluster whose domain is cozy.local the securityconfig job never
resolves its target, the .opendistro_security index is never created,
and the OpenSearch nodes never go Ready.

The domain the platform already holds could not reach the operator
before: _cluster stops at each package's own templates and never
reaches a vendored subchart, and the wrapper's values.yaml is not
templated. Carry it in the shared values Secret under the subchart key
instead, the same way the KEDA cluster domain travels, so the vendored
chart picks it up with no patch and a package rendered without the
Secret keeps the upstream cluster.local fallback.

A global key would have worked for the operator but reaches every
release on the cluster, and the vendored smee chart in bootbox cannot
render once global is non-empty. Scoping the value to the subchart
that consumes it avoids putting every other package on that path.

The diagnosis and the first working fix came from fuad00 in an earlier
pull request.

Adapted for release-1.6: the conflict in
packages/core/platform/templates/apps.yaml is resolved by keeping only
the opensearch-operator block. The keda block it was added next to on
main does not exist on this branch and is not brought in.

Assisted-by: LLM
Signed-off-by: Aleksei Sviridkin <[email protected]>
(cherry picked from commit 857ad4a)
Signed-off-by: Myasnikov Daniil <[email protected]>