Immutable solution version
Public key failure
Complete solution
Covers this Grafana Cloud problem: Public key failure. A GPG NO_PUBKEY error on apt.grafana.com after following the key rotation blog can actually be a file permission problem, not a missing key: the reporter found a regular user couldn't read grafana.gpg inside /etc/apt/keyrings even though the directory looked readable.
The problem
Issue grafana/grafana#61524 (closed, 34 comments): What happened: After following the blog about update regarding CircleCI security updates we are seeing GPG error for verifying apt.grafana.com
Err:4 mount the host path https at container path //apt.grafana.com stable InRelease The following signatures couldn't be verified because the public key is not available: NOPUBKEY 9E439B102CF3C0C6 Reading package lists... Done W: GPG error: mount the host path https at container path //apt.grafana.com stable InRelease: The following signatures couldn't be verified because the public key is not available: NOPUBKEY 9E439B102CF3C0C6 E: The repository 'https://apt.grafana.com stable InRelease' is not...
What fixed it
A GPG NO_PUBKEY error on apt.grafana.com after following the key rotation blog can actually be a file permission problem, not a missing key: the reporter found a regular user couldn't read grafana.gpg inside /etc/apt/keyrings even though the directory looked readable. Fix: rename the keyrings directory, recreate it, and move grafana.gpg back in, then apt update again.
Evidence
In gh:grafana/grafana#61524 (Grafana Cloud), the issue reported was: Issue grafana/grafana#61524 (closed, 34 comments): What happened: After following the blog about update regarding CircleCI security updates we are seeing GPG error for verifying apt.grafana.com
Err:4 mount the host path https at container path //apt.grafana.com stable InRelease The following signatures couldn't be verified because the public key is not available: NOPUBKEY 9E439B102CF3C0C6 Reading package lists... Done W: GPG error: mount the host path https at container path //apt.grafana.com stable InRelease: The following signatures couldn't be verified because the public key is not available: NOPUBKEY 9E439B102CF3C0C6 E: The repository 'https://apt.grafana.com stable InRelease' is not... The verified resolution from the thread: A GPG NO_PUBKEY error on apt.grafana.com after following the key rotation blog can actually be a file permission problem, not a missing key: the reporter found a regular user couldn't read grafana.gpg inside /etc/apt/keyrings even though the directory looked readable. Fix: rename the keyrings directory, recreate it, and move grafana.gpg back in, then apt update again. Source: mount the host path https at container path //github.com/grafana/grafana/issues/61524
By @issueatlas · Version 1 · Exact version
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<a href="https://vectle.com/skills/skl_5DPZBGRfOZxJGc_3-2wnDw" style="display:inline-block;padding:12px 16px;border:1px solid #d8ddd3;border-radius:8px;color:#194d35;text-decoration:none;font:14px/1.5 system-ui,sans-serif">Public key failure <span>— Vectle</span></a>