{"action":"created","issue":{"url":"https://api.github.com/repos/appc/cni/issues/84","labels_url":"https://api.github.com/repos/appc/cni/issues/84/labels{/name}","comments_url":"https://api.github.com/repos/appc/cni/issues/84/comments","events_url":"https://api.github.com/repos/appc/cni/issues/84/events","html_url":"https://github.com/appc/cni/issues/84","id":119924105,"number":84,"title":"macvlan: neighbours are not aware of ARP changes","user":{"login":"steveeJ","id":1181362,"avatar_url":"https://avatars.githubusercontent.com/u/1181362?v=3","gravatar_id":"","url":"https://api.github.com/users/steveeJ","html_url":"https://github.com/steveeJ","followers_url":"https://api.github.com/users/steveeJ/followers","following_url":"https://api.github.com/users/steveeJ/following{/other_user}","gists_url":"https://api.github.com/users/steveeJ/gists{/gist_id}","starred_url":"https://api.github.com/users/steveeJ/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/steveeJ/subscriptions","organizations_url":"https://api.github.com/users/steveeJ/orgs","repos_url":"https://api.github.com/users/steveeJ/repos","events_url":"https://api.github.com/users/steveeJ/events{/privacy}","received_events_url":"https://api.github.com/users/steveeJ/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/appc/cni/labels/component/plugins","name":"component/plugins","color":"d4c5f9"},{"url":"https://api.github.com/repos/appc/cni/labels/kind/bug","name":"kind/bug","color":"ff0000"},{"url":"https://api.github.com/repos/appc/cni/labels/priority/P1","name":"priority/P1","color":"eb6420"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-12-02T11:40:39Z","updated_at":"2015-12-02T18:08:28Z","closed_at":null,"body":"I would expect for the kernel to take care of this, but somehow it doesn't seem to work if IPs are reused. This issue stems from https://github.com/coreos/rkt/issues/1765."},"comment":{"url":"https://api.github.com/repos/appc/cni/issues/comments/161385032","html_url":"https://github.com/appc/cni/issues/84#issuecomment-161385032","issue_url":"https://api.github.com/repos/appc/cni/issues/84","id":161385032,"user":{"login":"eyakubovich","id":3586053,"avatar_url":"https://avatars.githubusercontent.com/u/3586053?v=3","gravatar_id":"","url":"https://api.github.com/users/eyakubovich","html_url":"https://github.com/eyakubovich","followers_url":"https://api.github.com/users/eyakubovich/followers","following_url":"https://api.github.com/users/eyakubovich/following{/other_user}","gists_url":"https://api.github.com/users/eyakubovich/gists{/gist_id}","starred_url":"https://api.github.com/users/eyakubovich/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/eyakubovich/subscriptions","organizations_url":"https://api.github.com/users/eyakubovich/orgs","repos_url":"https://api.github.com/users/eyakubovich/repos","events_url":"https://api.github.com/users/eyakubovich/events{/privacy}","received_events_url":"https://api.github.com/users/eyakubovich/received_events","type":"User","site_admin":false},"created_at":"2015-12-02T18:08:28Z","updated_at":"2015-12-02T18:08:28Z","body":"Since containers tend to be much more short lived than machines, ARP caching should be much less aggressive in the system. This is easier said than done, of course. For Linux based neighbors, setting `net.ipv4.neigh.default.gc_thresh1=0` should help (see https://groups.google.com/forum/#!searchin/coreos-user/arp/coreos-user/FG5B0PxP7Wc/4Y-JwRSOFAAJ).\r\n\r\nAn obvious improvement suggested by @steveeJ is to add an unsolicited ARP broadcast into `macvlan` plugin. Maybe even send 3 in a row (with something like 100ms delay) to reduce the chance of it getting dropped."}}