* proto: add RaftLeadershipTransfer RPC for forced leader change
Add new gRPC RPC and messages for leadership transfer:
- RaftLeadershipTransferRequest: optional target_id and target_address
- RaftLeadershipTransferResponse: previous_leader and new_leader
This enables graceful leadership transfer before master maintenance,
reducing errors in filers during planned maintenance windows.
Ref: https://github.com/seaweedfs/seaweedfs/issues/7527
* proto: regenerate Go files for RaftLeadershipTransfer
Generated from master.proto changes.
* master: implement RaftLeadershipTransfer gRPC handler
Add gRPC handler for leadership transfer with support for:
- Transfer to any eligible follower (when target_id is empty)
- Transfer to a specific server (when target_id and target_address are provided)
Uses hashicorp/raft LeadershipTransfer() and LeadershipTransferToServer() APIs.
Returns the previous and new leader in the response.
* shell: add cluster.raft.leader.transfer command
Add weed shell command for graceful leadership transfer:
- Displays current cluster status before transfer
- Supports auto-selection of target (any eligible follower)
- Supports targeted transfer with -id and -address flags
- Provides clear feedback on success/failure with troubleshooting tips
Usage:
cluster.raft.leader.transfer
cluster.raft.leader.transfer -id <server_id> -address <grpc_address>
* master: add unit tests for raft gRPC handlers
Add tests covering:
- RaftLeadershipTransfer with no raft initialized
- RaftLeadershipTransfer with target_id but no address
- RaftListClusterServers with no raft initialized
- RaftAddServer with no raft initialized
- RaftRemoveServer with no raft initialized
These tests verify error handling when raft is not configured.
* shell: add tests for cluster.raft.leader.transfer command
Add tests covering:
- Command name and help text validation
- HasTag returns false for ResourceHeavy
- Validation of -id without -address
- Argument parsing with unknown flags
* master: clarify that leadership transfer requires -raftHashicorp
The default raft implementation (seaweedfs/raft, a goraft fork) does not
support graceful leadership transfer. This feature is only available when
using hashicorp raft (-raftHashicorp=true).
Update error messages and help text to make this requirement clear:
- gRPC handler returns specific error for goraft users
- Shell command help text notes the requirement
- Added test for goraft case
* test: use strings.Contains instead of custom helper
Replace custom contains/containsHelper functions with the standard
library strings.Contains for better maintainability.
* shell: return flag parsing errors instead of swallowing them
- Return the error from flag.Parse() instead of returning nil
- Update test to explicitly assert error for unknown flags
* test: document integration test scenarios for Raft leadership transfer
Add comments explaining:
- Why these unit tests only cover 'Raft not initialized' scenarios
- What integration tests should cover (with multi-master cluster)
- hashicorp/raft uses concrete types that cannot be easily mocked
* fix: address reviewer feedback on tests and leader routing
- Remove misleading tests that couldn't properly validate their
documented behavior without a real Raft cluster:
- TestRaftLeadershipTransfer_GoraftNotSupported
- TestRaftLeadershipTransfer_ValidationTargetIdWithoutAddress
- Change WithClient(false) to WithClient(true) for RaftLeadershipTransfer
RPC to ensure the request is routed to the current leader
* Improve cluster.raft.transferLeader command
- Rename command from cluster.raft.leader.transfer to cluster.raft.transferLeader
- Add symmetric validation: -id and -address must be specified together
- Handle case where same leader is re-elected after transfer
- Add test for -address without -id validation
- Add docker compose file for 5-master raft cluster testing
Chris Lu
Konstantin Lebedev
Patrick Schmidt
chrislu