certmanager-dns01-gke-private-cluster

certmanager-dns01-gke-private-cluster is a skill for Claude Code, Codex from divinevideo/divine-mobile. It costs 189 tokens per session (1,856 once invoked), scanned D, original, MPL-2.0.

A troubleshooting guide for cert-manager, the Kubernetes tool that requests and renews HTTPS certificates, when DNS01 verification stays pending in private Google Kubernetes Engine clusters.

In plain words
What is it for?
Use it with Cloudflare DNS, private GKE clusters, and ACME challenges stuck on propagation checks despite successful lookups from other locations.
Why use it?
A certificate request can fail its DNS check even when the required TXT record exists, because DNS queries inside the cluster may use a path that returns the wrong result.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code; installed under .agents/ (shared by several agents).

Good fit Use it with Cloudflare DNS, private GKE clusters, and ACME challenges stuck on propagation checks despite successful lookups from other locations.

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Install with agentmods
npx agentmods add skills/divinevideo/divine-mobile/certmanager-dns01-gke-private-cluster
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add divinevideo/divine-mobile --skill certmanager-dns01-gke-private-cluster
Clone the repo
git clone --depth 1 https://github.com/divinevideo/divine-mobile

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for certmanager-dns01-gke-private-cluster

README.md
[![agentmods](https://agentmods.dev/badge/skills/divinevideo/divine-mobile/certmanager-dns01-gke-private-cluster/github.svg)](https://agentmods.dev/skills/divinevideo/divine-mobile/certmanager-dns01-gke-private-cluster)
Your own site
<a href="https://agentmods.dev/skills/divinevideo/divine-mobile/certmanager-dns01-gke-private-cluster"><img src="https://agentmods.dev/badge/skills/divinevideo/divine-mobile/certmanager-dns01-gke-private-cluster/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for certmanager-dns01-gke-private-cluster

Your own site · 80×15
<a href="https://agentmods.dev/skills/divinevideo/divine-mobile/certmanager-dns01-gke-private-cluster"><img src="https://agentmods.dev/badge/skills/divinevideo/divine-mobile/certmanager-dns01-gke-private-cluster.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 189 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,856 The whole file, excluding the scripts and references it only reads on demand.
Security scan D 3 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00189 $0.01856
Opus 5 $0.00095 $0.00928
Sonnet 5 $0.00038 $0.00371
Haiku 4.5 $0.00019 $0.00186

Measured 11d ago against content hash f14db7c55a5c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade D, and why

certmanager-dns01-gke-private-cluster scanned grade D with 3 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

chmod 600 /tmp/certbot-cf/cloudflare.ini

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

rm -rf /tmp/certbot-cf

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s https://upload.example.com/
.agents/skills/certmanager-dns01-gke-private-cluster/SKILL.md · 171 lines

How it starts

The opening of the file, as written. The whole thing — 171 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cert-Manager DNS01 Challenge Failure in GKE Private Clusters

Problem

Cert-manager DNS01 ACME challenges get stuck in "pending" state indefinitely inside GKE private clusters. The propagation check fails with "DNS record for X not yet propagated" even though the TXT records are correctly created in Cloudflare and verifiable from everywhere — including from inside the cluster using busybox pods.

Context / Trigger Conditions

  • cert-manager with Cloudflare DNS01 solver
  • GKE private cluster (private nodes, public endpoint) with Cloud NAT
  • Challenges show presented: true but state: pending for hours
  • cert-manager logs show: "propagation check failed" err="DNS record for \"example.com\" not yet propagated"
  • dig TXT _acme-challenge.example.com from outside returns correct value
  • busybox nslookup from inside cluster also returns correct value
  • Certificate resource shows Ready: False with reason: RequestChanged

Root Causes Discovered

1. Google Cloud intercepts DNS to 8.8.8.8

Inside GKE VPCs, DNS queries to 8.8.8.8 are intercepted by Google Cloud infrastructure. For Cloudflare-managed domains, this can return NXDOMAIN even when the record exists. This is because Google routes 8.8.8.8 through their internal DNS infrastructure which may have different resolution behavior than the public Google DNS service.

Verification:

# From inside cluster - returns NXDOMAIN
kubectl run dns-test --image=busybox:1.36 --rm -i --restart=Never -- \
  nslookup -type=TXT _acme-challenge.example.com 8.8.8.8

# From inside cluster - returns correct result
kubectl run dns-test --image=busybox:1.36 --rm -i --restart=Never -- \
  nslookup -type=TXT _acme-challenge.example.com 1.1.1.1

2. Cert-manager propagation check still fails with correct resolvers

Even after configuring --dns01-recursive-nameservers=1.1.1.1:53,1.0.0.1:53 and --dns01-recursive-nameservers-only=true, cert-manager's propagation check may still fail. The Go DNS library used by cert-manager (miekg/dns) behaves differently from busybox's nslookup. The exact cause is unclear but may relate to:

  • DNS response parsing differences between miekg/dns and system resolvers
  • TCP vs UDP DNS query differences
  • Internal cert-manager caching or timing issues
  • Cloud NAT interaction with DNS traffic patterns

Read the full file on GitHub · 171 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 171 lines · 189 tokens per session scan D f14db7c55a5c

Subscribe to this mod's changes

certmanager-dns01-gke-private-cluster is a skill published in the GitHub repository divinevideo/divine-mobile (265 stars, last pushed today), licensed MPL-2.0. It adds 189 tokens to every session and 1,856 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it D with 3 findings (asks for root, recursive force delete, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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