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CoreDNS

CoreDNS is the DNS server running in every Kubernetes cluster, resolving Service names and forwarding external queries upstream.

Unlike most charts in this repo, this is not a wrapper around an upstream chart — it deploys no CoreDNS of its own. It is a small KubeAid-authored chart that manages the coredns-custom ConfigMap, the extension point that managed CoreDNS deployments (notably Azure AKS) import for custom server blocks.

Why it's in KubeAid​

On AKS the CoreDNS deployment is managed by the platform and cannot be edited directly; custom DNS forwarding has to go through the coredns-custom ConfigMap. This chart lets you declare those conditional forwarders in Git and roll them out via Argo CD like everything else, instead of hand-editing a ConfigMap — the typical use case being private/internal zones that must resolve through specific resolvers (e.g. an Azure DNS Private Resolver).

Key values / KubeAid-specific configuration​

Everything lives under the customDNS key (disabled by default):

customDNS:
  enabled: true
  cache: 30              # optional: cache duration in seconds
  dnsServers: >-         # ordered, one per line — the forward targets
    1.1.1.1
    8.8.8.8
  domainList:            # zones whose queries go to the servers above
    - example.com
    - example.io

For each domain in domainList, the chart renders a CoreDNS server block using the forward plugin (with errors, log, and optional cache) into the coredns-custom ConfigMap in the release namespace.

Operational notes​

  • The ConfigMap only takes effect on CoreDNS setups that import coredns-custom (AKS does this out of the box). On self-managed clusters this chart renders the ConfigMap but nothing consumes it unless you wire that up.