Release 2.4.0
Fencing and failover
- The new fencing feature protects a replicaset from the presence of
multiple leaders when the network is partitioned. It forces an
isolated leader to become read-only.
- New failover parameter `failover_timout` specifies the time (in
seconds) used by membership to mark `suspect` members as `dead` which
triggers failover. The default value of `failover_timeout` increased
from 3 to 20 seconds (**important change**).
- The `rpc_*` functions now consider `suspect` members as healthy to be
in agreement with failover (**important change**).
- All these parameters, `fencing_enabled`, `fencing_pause`,
`fencing_timeout`, are available for customization via Lua and
GraphQL API, and in WebUI too.
Zones and zone distances
- Add support of replica weights and zones via a cluster-wide config new
section `zone_distances` and a server parameter `zone`.
- Update server details dialog in WebUI.
Issues and suggestions
- Fix `upstream.idle` issue tolerance to avoid unnecessary warnings
"Replication: long idle (1 > 1)".
- Indicate config checksum mismatch in the issues list.
- Indicate the change of `arvertise_uri` in the issues list.
- Show an issue if the cluster-wide config is locked on an instance.
- Show a suggestion to heal the cluster after relocating servers and
changing their `advertise_uri`.
- Don't get stuck in `ConnectingFullmesh` state when an instance is
restarted with a different `advertise_uri`. Also, keep the "Server
details" dialog in WebUI operable in this case.
- Allow applying config when an instance is in `OperationError` state.
It doesn't cause a loss of quorum anymore.
Hot-reload
- Add new feature for hot reloading roles code without restarting an
instance: `cartridge.reload_roles()`. The feature is experimental
and should be enabled explicitly:
`cartridge.cfg({roles_reload_allowed = true})`. Use it with caution.
Miscellaneous enhancements
- New `cartridge.cfg` option `swim_broadcast` to manage instances
auto-discovery on start. Default: true.
- New argparse options for tarantool 2.5+: `replication_synchro_quorum`,
`replication_synchro_timeout`, `memtx_use_mvcc_engine`.
- Stop vshard fibers when the corresponding role is disabled.
- Make `console.listen` error more clear when `console_sock` exceeds
`UNIX_PATH_MAX` limit.
- Allow removing spaces from DDL schema for the sake of `drop`
migrations.
- Make DDL schema validation stricter. Forbid redundant keys in schema
top-level and make `spaces` mandatory.
- Refresh interval and stat refresh period variables can be customized
via frontend-core `set_variable` feature or at runtime.
- Properly display errors on WebUI pages "Users" and "Code".