The monmap msgr2 branch is is getting close to merge: https://github.com/ceph/ceph/pull/25360 This has a placeholder protocol in place for now (Ricardo's actual msgr2 implementation will follow shortly after), but it changes around the rest of the ceph code to deal with the dual implementations. The main visible difference is that entity_addr_t will now render with either a v1: or v2: prefix, and most places where you used to see a single addr will now have an entity_addrvec_t. For example, $ ceph mon dump dumped monmap epoch 1 epoch 1 fsid 91e4f964-d1f4-4900-835f-de4e3e36c7c7 last_changed 2018-12-05 12:55:58.578101 created 2018-12-05 12:55:58.578101 0: [v2:127.0.0.1:40376/0,v1:127.0.0.1:40377/0] mon.a Same goes for the osdmap, fsmap, mgrmap, etc. The parse() method(s) are similarly changed: they understand the v1 and v2 prefixes, and if no prefix is specified, they (generally) parse a v2 address. (There are exceptions here with the mon addresses, see below.) There are a few new config options, both true by default: ms bind msgr1 = true ms bind msgr2 = true There's also ms bind ipv4 = true ms bind ipv6 = false # by default Notably, this means daemons can now do dual-stack IPv4 and IPv6 (or will be able to with some minor fiddling with the client-side code that chooses which addr to connect to). Teuthology's ceph task has a few new options, both true by default, but set to false for upgrade tasks that start by installing old versions. These control what addr types the cluster's initial monmap gets: overrides: ceph: mon_bind_addrvec: true mon_bind_msgr2: true The MonMap::build_initial() method, which is used for creating the initial monmap during mkfs (if/when the mons are based on mon_host, as they are with ceph-deploy, but not with teuthology or vstart), will infer whether an address is v1 or v2 if the port is specified as 6789 or 3300 respectively. If the port is unspecified, both the v1 and v2 ports are tried during the MonClient probe stage (once we connect to someone and get the real monmap then we know for sure). Anyway, please think about any fallout that we might see as a result of the new rendering or parsing for IP addresses, or anything else that might be affected by this change! Thanks- sage
