On Mon, Dec 16, 2024 at 2:19 AM Akhil Singh ***@***.***> wrote: You’ve discovered that using a rewrite rule in CoreDNS to map your external FQDNs to Kubernetes service hostnames works well. The challenge now is that you want to replicate this pattern for multiple developers, each with their own namespace, but still use only one CoreDNS instance for the entire cluster. Key Points: 1. Problem Setup: • Originally, you had a rewrite rule like: rewrite stop name regex (.*).dev.mycompany.com. caddy.default.svc.cluster.local This takes any query ending in .dev.mycompany.com and rewrites it to caddy.default.svc.cluster.local. • Now you want each developer to have their own namespace, e.g. mynamespace. The target should become: rewrite stop name regex (.*).dev.mycompany.com. caddy.mynamespace.svc.cluster.local • Doing this for every developer namespace individually doesn’t scale, and you only have one CoreDNS instance for the cluster. CoreDNS’s rewrite plugin supports using capture groups from the regex in the replacement string. Let’s assume each developer’s namespace is represented by the subdomain. For example: • alice.dev.mycompany.com should map to caddy.alice.svc.cluster.local • bob.dev.mycompany.com should map to caddy.bob.svc.cluster.local You can achieve this with: rewrite stop name regex ([^.] ).dev.mycompany.com. caddy.{1}.svc.cluster.local Explanation of the regex: • ([^.] ) matches one or more characters that are not a dot. This captures the subdomain part before .dev.mycompany.com. • .dev.mycompany.com. matches the literal .dev.mycompany.com. suffix. The {1} in the replacement string refers to the first capturing group (the subdomain), allowing CoreDNS to rewrite the query dynamically based on the captured text. For example, if the query is bob.dev.mycompany.com., then {1} = bob, resulting in caddy.bob.svc.cluster.local. With this single rewrite directive, you can handle all developers’ namespaces. Any xxxxx.dev.mycompany.com. query is automatically rewritten to caddy.xxxxx.svc.cluster.local, where xxxxx corresponds to the namespace name. There’s no need to run multiple CoreDNS instances or maintain separate rewrite rules for each developer. In Summary: By using a capture group and referencing it in the rewritten name, you can keep a single, cluster-wide CoreDNS configuration that dynamically maps the requested subdomain to a corresponding namespace’s caddy service address. — Reply to this email directly, view it on GitHub <#6919 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AKE5LWW2VV5FARVDQDT5ODL2F2SKNAVCNFSM6AAAAABPVTZ2NSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKNBVGE3TGMJZGE> . You are receiving this because you authored the thread.Message ID: ***@***.***>