On-disk formats, or even data structure formats, may be changed during an upgrade. Services wishing to do so, may so do it via the PaxosService::upgrade_format() call path. There is no formalized, unified format versioning; the PaxosService class keeps track of its format_version through a key in the store, assumed an unsigned int, but it will be the service’s responsibility to give meaning to those versions.
versions are represented with a single unsigned int. By default, the value zero represents the absence of a formal upgraded format. The first format version was introduced in Dumpling; clusters upgrading to Dumpling saw their format version being increased from zero to one.:
0 to 1 - introduced in v0.65, dev release for v0.67 dumpling 1 to 2 - introduced in v12.0.2, dev release for luminous 2 to 3 - introduced in mimic 0 - all clusters pre-dumpling 1 - all clusters dumpling+ and pre-luminous 2 - all clusters luminous+ and pre-mimic 3 - all clusters mimic+ version 1: introduces new-style monitor caps (i.e., profiles) version 2: introduces mgr caps and bootstrap-mgr key version 3: creates all bootstrap and admin keys if they don't yet exist
format_version set on PaxosService::refresh()::
- initially called from Monitor::refresh_from_paxos - initially called from Monitor::init_paxos() - initially called from Monitor::preinit()
AuthMonitor::upgrade_format() called by PaxosService::_active()::
- called from C_Committed callback, from PaxosService::propose_pending() - called from C_Active callback, from PaxosService::_active() - called from PaxosService::election_finished() - on a freshly deployed cluster, upgrade_format() will be first called *after* create_initial(). - on an existing cluster, upgrade_format() will be called after the first election. - upgrade_format() is irrelevant on a freshly deployed cluster, as there is no format to upgrade at this point.
if format_version >= current_version then format is uptodate, return.
if features doesn’t contain LUMINOUS then current_version = 1
else if features doesn’t contain MIMIC then current_version = 2
else current_version = 3
if format_version == 0::
- upgrade to format version 1 - move to new-style monitor caps (i.e., profiles): - set daemon profiles for existing entities - set profile for existing bootstrap keys
if format_version == 1::
- upgrade to format version 2 - for existing entities: - add new cap for mgr - for existing 'mgr' entities, fix 'mon' caps due to bug from kraken setting 'allow \*', and set 'allow profile mgr' instead. - add bootstrap-mgr key.
if format_version == 2::
- upgrade to format version 3 - create all bootstrap keys if they don't currently exist