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1. IL-0159 Docker Hub rate-limited Linode's IPv6 address space with 429 Too Many Requests, breaking image pulls for LKE and LKE-E clusters

   Linode2025

   Symptoms

   From about 21:38 UTC on 5 February 2025, image pulls from Docker Hub over IPv6 failed with 429 Too Many Requests errors across several Linode regions. Both unauthenticated and authenticated pull requests were refused.

   Image pull failures

   Trigger

   Docker Hub's abuse prevention measures started rate-limiting image pulls coming from Linode's IPv6 address space.

   Root cause

   Dependency failure

   Component

   Container registry and its credentialsVPC DNS resolver

   Contributing factor

   Unknown limit

   Detection

   The rate limiting began at about 21:38 UTC. The first status post, at 22:48 UTC, said Linode was aware of an issue with Docker Hub over IPv6 causing rate limiting and was investigating, and at 01:06 UTC on 6 February the status page said the issue had been identified as rate limiting of image pull requests to Docker Hub over IPv6.

   Remediation

   • changed the DNS resolvers to return an A record instead of an AAAA record so image pulls to Docker Hub used IPv4

   Action items

   • Find long-term solutions so that Docker Hub's abuse prevention measures do not affect Linode services

   Lessons

   A registry's abuse limit that groups IPv6 addresses by their first 64 bits can block a provider's whole address range at once, and authentication does not help. Answering DNS lookups with IPv4 addresses only was the quick way to move image pulls off the blocked range.

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