k8s-coredns-troubleshooting SKILL.md skillA
k8s-coredns-troubleshooting from k8s-servant/k8s-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add k8s-servant/k8s-skills/k8s-coredns-troubleshooting@git:20261025.6531d71Pins git:20261025.6531d71 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- k8s-servant/k8s-skills
- Path
skills/k8s-coredns-troubleshooting/SKILL.md- Versions recorded
- 1
- Latest version
- git:20261025.6531d71, committed Oct 25, 2026
- Size
- 12,056 bytes
- Repository stars
- 35
- License
- Apache-2.0
Use when cluster DNS itself misbehaves on Kubernetes: CoreDNS pods in CrashLoopBackOff ("Error during parsing: Unknown directive", "plugin/loop: Loop ... detected"), "reload failed" after a Corefile edit, external names failing while Service names resolve (";; connection timed out; no servers could be reached", SERVFAIL, "plugin/errors: 2 ... i/o timeout"), one domain or stub domain failing, rewrite or hosts entries that do not work, "Plugins not ready: \"kubernetes\"", REFUSED or…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# CoreDNS troubleshooting
Find out why CoreDNS does not answer a name the way it should, and propose a fix. **Read
first, ask before changing.** Run the investigation commands freely. Run a command under
an "Ask first" line only after the user approves that exact command; if your credentials
do not allow it, give it to the user to run. Never run a "Proposed fix"; hand it to the
user.
CoreDNS runs in `kube-system` as the Deployment `coredns` (label `k8s-app=kube-dns`),
behind the Service `kube-dns`, and reads its configuration, the **Corefile**, from the
ConfigMap `coredns`. Each server block (`.:53 { ... }`, or `example.com:53 { ... }` for
one domain) lists plugins: `kubernetes` answers names under `cluster.local`, `forward`
sends everything else upstream (by default to the node's `/etc/resolv.conf`), `cache`,
`rewrite` and `hosts` change answers, `errors` logs failures, `loop` stops CoreDNS when
it would query itself, and `reload` reads an edited Corefile about 30 seconds after the
ConfigMap reaches the pod. The default Corefile has no `log` plugin, so successful
queries and NXDOMAIN answers are not logged.
…Read the whole file at its exact version.
How to install
mdr add k8s-servant/k8s-skills/k8s-coredns-troubleshooting@sha256:bdb75e487620036fThe line at the top of this page pins the label git:20261025.6531d71, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_vxu4qpion4sbla7e)
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Versions
The registry has recorded 1 version of this file, committed on Oct 25, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (12056 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
k8s-servant/k8s-skills · 35 stars · license Apache-2.0 · pushed 2026-10-31 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_vxu4qpion4sbla7e GET https://markdownregistry.com/api/v1/resolve?ref=k8s-servant/k8s-skills/k8s-coredns-troubleshooting GET https://markdownregistry.com/api/v1/blob/bdb75e487620036f3d6391120a1dd52bccc74200ddce8d285e03925efcc1002e
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.