Comment 11 for bug 1780348

Reviewed: https://review.openstack.org/639985
Committed: https://git.openstack.org/cgit/openstack/charm-neutron-gateway/commit/?id=53b58388d37a3b2b2674989e09c216ae7ce76c9e
Submitter: Zuul
Branch: master

commit 53b58388d37a3b2b2674989e09c216ae7ce76c9e
Author: Pete Vander Giessen <email address hidden>
Date: Wed Feb 27 16:04:27 2019 +0100

    Added gc_threshold overrides to sysctl.conf

    When clouds have a large number of hosts, the default size of the ARP
    cache is too small. The cache can overflow, which means that the
    system has no way to reach some ip addresses.

    Setting the threshold limits higher addresses the situation, in a
    reasonably safe way (the maximum impact is 5MB or so of additional RAM
    used). Docs on ARP at http://man7.org/linux/man-pages/man7/arp.7.html,
    and more discussion of the issue in the bug.

    Change-Id: I701141784224f5f870f6da73a24bed8015694409
    Closes-Bug: 1780348