an existing stale ARP entry for IP1 with MAC1 should exist Ģ. Though I don't have easy steps to reproduce, I will try to explain the state in which the system is stuck with broken ARP entries, the following should happen:ġ. How reproducible: I couldn't come up with a script that would show the issue isolated from OpenStack and its test suite, but see steps below. Version-Release number of selected component (if applicable): 3.10.0-514.22.1.el7 Besides missing patches, it would need some refinement to accommodate for KABI stability requirements set for RHEL kernels. pcap) that after 5 seconds of not being able to reach the lladdr, kernel correctly issues a ARP probe, updates lladdr in ARP table with the new MAC address, and successfully establishes connections to the IP address.Īn attempt to backport (most of) those patches from the series that is proved to work can be found at: (note it doesn't include sctp and the last cleanup patch since I didn't think that could affect my testing, and indeed it did not). With patches applied, I see (in captured. With (most of) those patches applied to RHEL7 kernel, I was able to pass OpenStack scenario test runs. #BOOXTER FILE EXTENSION UPDATE#So seemingly unrelated traffic actually "confirms" entries, which explains why not a single ARP probe to update the affected ARP entries is sent during failing test runs. The patch series tackles the problem where confirmations happen on dst_entry structure that can be reused for multiple ARP entries. This is because till 4.11, the following patch series was not included: Month-long investigation uncovered that in particular situations, ARP table entries may cycle through STALE-DELAY-REACHABLE states without issuing a single ARP probe even when no matching upper layer protocol traffic arrives from the entry lladdr. Description of problem: in downstream OpenStack CI, we experience random connectivity issues:
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