{"action":"created","issue":{"url":"https://api.github.com/repos/openshift/origin/issues/6597","labels_url":"https://api.github.com/repos/openshift/origin/issues/6597/labels{/name}","comments_url":"https://api.github.com/repos/openshift/origin/issues/6597/comments","events_url":"https://api.github.com/repos/openshift/origin/issues/6597/events","html_url":"https://github.com/openshift/origin/pull/6597","id":125669916,"number":6597,"title":"Change default ClusterNetworkCIDR and HostSubnetLength","user":{"login":"danwinship","id":96040,"avatar_url":"https://avatars.githubusercontent.com/u/96040?v=3","gravatar_id":"","url":"https://api.github.com/users/danwinship","html_url":"https://github.com/danwinship","followers_url":"https://api.github.com/users/danwinship/followers","following_url":"https://api.github.com/users/danwinship/following{/other_user}","gists_url":"https://api.github.com/users/danwinship/gists{/gist_id}","starred_url":"https://api.github.com/users/danwinship/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/danwinship/subscriptions","organizations_url":"https://api.github.com/users/danwinship/orgs","repos_url":"https://api.github.com/users/danwinship/repos","events_url":"https://api.github.com/users/danwinship/events{/privacy}","received_events_url":"https://api.github.com/users/danwinship/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":5,"created_at":"2016-01-08T18:51:34Z","updated_at":"2016-01-18T22:58:52Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/openshift/origin/pulls/6597","html_url":"https://github.com/openshift/origin/pull/6597","diff_url":"https://github.com/openshift/origin/pull/6597.diff","patch_url":"https://github.com/openshift/origin/pull/6597.patch"},"body":"From https://trello.com/c/bCmIOTeJ/ (\"SDN out of box configuration and scale\"). This patch changes the SDN defaults in two ways:\r\n\r\n1. Change the default cluster network range from `10.1.0.0/16` to `10.128.0.0/16`. With #6349 it is now possible to expand a deployed cluster to a larger CIDR range, as long as the new network overlaps the old one. But with the default value of `10.1.0.0/16`, any expansion would have to also cover `10.0.0.0/16`, which is the section of `10.0.0.0/8` most likely to already be used by some other network (which is presumably why we currently default to `10.1.0.0/16` not `10.0.0.0/16`). So change the default to `10.128.0.0/16`, so that expanding it would use other high-numbered subnets.\r\n2. Change HostSubnetLength to 7. The old default of 8, with a /16 network, allows for 256 nodes with 254 pods each. But we don't expect nodes to work well with [more than 100 containers](http://lists.openshift.redhat.com/openshift-archives/dev/2016-January/msg00001.html), so it makes\r\nsense to default to fewer pods and more nodes (512 nodes / 126 pods). (We could drop it further, but we don't currently support changing HostSubnetLength in a deployed cluster, so expanding ClusterNetworkCIDR can only increase the number of nodes, not the number of pods per node, so I figured it was better to err on the side of too high a default value.)\r\n\r\nThis is just a proposal; we might want to change only one of those two things, or neither, for backward-compatibility/documentation reasons... Thoughts?\r\n\r\n@openshift/networking "},"comment":{"url":"https://api.github.com/repos/openshift/origin/issues/comments/172676015","html_url":"https://github.com/openshift/origin/pull/6597#issuecomment-172676015","issue_url":"https://api.github.com/repos/openshift/origin/issues/6597","id":172676015,"user":{"login":"pravisankar","id":1258630,"avatar_url":"https://avatars.githubusercontent.com/u/1258630?v=3","gravatar_id":"","url":"https://api.github.com/users/pravisankar","html_url":"https://github.com/pravisankar","followers_url":"https://api.github.com/users/pravisankar/followers","following_url":"https://api.github.com/users/pravisankar/following{/other_user}","gists_url":"https://api.github.com/users/pravisankar/gists{/gist_id}","starred_url":"https://api.github.com/users/pravisankar/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/pravisankar/subscriptions","organizations_url":"https://api.github.com/users/pravisankar/orgs","repos_url":"https://api.github.com/users/pravisankar/repos","events_url":"https://api.github.com/users/pravisankar/events{/privacy}","received_events_url":"https://api.github.com/users/pravisankar/received_events","type":"User","site_admin":false},"created_at":"2016-01-18T22:58:52Z","updated_at":"2016-01-18T22:58:52Z","body":"These default values seems reasonable to me.\r\nCan we also allow expanding service network similar to cluster network?"}}