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*: address comments

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This commit is contained in:
Jingyi Hu 2019-05-16 14:55:33 -07:00
parent 6bf609b96d
commit 23511d21ec
2 changed files with 9 additions and 3 deletions
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3
Documentation/op-guide/runtime-configuration.md
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@ -132,8 +132,6 @@ and to reduce cluster downtime when the new member is added, it is recommended t
as a learner until it catches up. This can be described as a three step process:
* Add the new member as learner via [gRPC members API][member-api-grpc] or the `etcdctl member add --learner` command.
Note that v2 [HTTP member API][member-api] does not support this feature. (If user wants to use HTTP,
etcd provides a JSON [gRPC gateway][grpc-gateway], which serves a RESTful proxy that translates HTTP/JSON requests into gRPC messages.)
* Start the new member with the new cluster configuration, including a list of the updated members (existing members + the new member).
This step is exactly the same as before.
@ -244,5 +242,4 @@ It is enabled by default.
[member migration]: ../v2/admin_guide.md#member-migration
[remove member]: #remove-a-member
[runtime-reconf]: runtime-reconf-design.md
[grpc-gateway]: https://github.com/grpc-ecosystem/grpc-gateway
[error cases when promoting a member]: #error-cases-when-promoting-a-learner-member

9
etcdserver/server.go
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@ -1635,6 +1635,9 @@ func (s *EtcdServer) RemoveMember(ctx context.Context, id uint64) ([]*membership
// PromoteMember promotes a learner node to a voting node.
func (s *EtcdServer) PromoteMember(ctx context.Context, id uint64) ([]*membership.Member, error) {
// only raft leader has information on whether the to-be-promoted learner node is ready. If promoteMember call
// fails with ErrNotLeader, forward the request to leader node via HTTP. If promoteMember call fails with error
// other than ErrNotLeader, return the error.
resp, err := s.promoteMember(ctx, id)
if err != ErrNotLeader {
return resp, err
@ -1666,6 +1669,12 @@ func (s *EtcdServer) PromoteMember(ctx context.Context, id uint64) ([]*membershi
return nil, ErrCanceled
}
// promoteMember checks whether the to-be-promoted learner node is ready before sending the promote
// request to raft.
// The function returns ErrNotLeader if the local node is not raft leader (therefore does not have
// enough information to determine if the learner node is ready), returns ErrLearnerNotReady if the
// local node is leader (therefore has enough information) but decided the learner node is not ready
// to be promoted.
func (s *EtcdServer) promoteMember(ctx context.Context, id uint64) ([]*membership.Member, error) {
if err := s.checkMembershipOperationPermission(ctx); err != nil {
return nil, err