Files
zrepl/replication/logic/pdu/pdu.proto
Christian Schwarz 58c08c855f new features: {resumable,encrypted,hold-protected} send-recv, last-received-hold
- **Resumable Send & Recv Support**
  No knobs required, automatically used where supported.
- **Hold-Protected Send & Recv**
  Automatic ZFS holds to ensure that we can always resume a replication step.
- **Encrypted Send & Recv Support** for OpenZFS native encryption.
  Configurable at the job level, i.e., for all filesystems a job is responsible for.
- **Receive-side hold on last received dataset**
  The counterpart to the replication cursor bookmark on the send-side.
  Ensures that incremental replication will always be possible between a sender and receiver.

Design Doc
----------

`replication/design.md` doc describes how we use ZFS holds and bookmarks to ensure that a single replication step is always resumable.

The replication algorithm described in the design doc introduces the notion of job IDs (please read the details on this design doc).
We reuse the job names for job IDs and use `JobID` type to ensure that a job name can be embedded into hold tags, bookmark names, etc.
This might BREAK CONFIG on upgrade.

Protocol Version Bump
---------------------

This commit makes backwards-incompatible changes to the replication/pdu protobufs.
Thus, bump the version number used in the protocol handshake.

Replication Cursor Format Change
--------------------------------

The new replication cursor bookmark format is: `#zrepl_CURSOR_G_${this.GUID}_J_${jobid}`
Including the GUID enables transaction-safe moving-forward of the cursor.
Including the job id enables that multiple sending jobs can send the same filesystem without interfering.
The `zrepl migrate replication-cursor:v1-v2` subcommand can be used to safely destroy old-format cursors once zrepl has created new-format cursors.

Changes in This Commit
----------------------

- package zfs
  - infrastructure for holds
  - infrastructure for resume token decoding
  - implement a variant of OpenZFS's `entity_namecheck` and use it for validation in new code
  - ZFSSendArgs to specify a ZFS send operation
    - validation code protects against malicious resume tokens by checking that the token encodes the same send parameters that the send-side would use if no resume token were available (i.e. same filesystem, `fromguid`, `toguid`)
  - RecvOptions support for `recv -s` flag
  - convert a bunch of ZFS operations to be idempotent
    - achieved through more differentiated error message scraping / additional pre-/post-checks

- package replication/pdu
  - add field for encryption to send request messages
  - add fields for resume handling to send & recv request messages
  - receive requests now contain `FilesystemVersion To` in addition to the filesystem into which the stream should be `recv`d into
    - can use `zfs recv $root_fs/$client_id/path/to/dataset@${To.Name}`, which enables additional validation after recv (i.e. whether `To.Guid` matched what we received in the stream)
    - used to set `last-received-hold`
- package replication/logic
  - introduce `PlannerPolicy` struct, currently only used to configure whether encrypted sends should be requested from the sender
  - integrate encryption and resume token support into `Step` struct

- package endpoint
  - move the concepts that endpoint builds on top of ZFS to a single file `endpoint/endpoint_zfs.go`
    - step-holds + step-bookmarks
    - last-received-hold
    - new replication cursor + old replication cursor compat code
  - adjust `endpoint/endpoint.go` handlers for
    - encryption
    - resumability
    - new replication cursor
    - last-received-hold

- client subcommand `zrepl holds list`: list all holds and hold-like bookmarks that zrepl thinks belong to it
- client subcommand `zrepl migrate replication-cursor:v1-v2`
2020-02-14 22:00:13 +01:00

134 lines
3.4 KiB
Protocol Buffer

syntax = "proto3";
option go_package = "pdu";
service Replication {
rpc Ping(PingReq) returns (PingRes);
rpc ListFilesystems(ListFilesystemReq) returns (ListFilesystemRes);
rpc ListFilesystemVersions(ListFilesystemVersionsReq)
returns (ListFilesystemVersionsRes);
rpc DestroySnapshots(DestroySnapshotsReq) returns (DestroySnapshotsRes);
rpc ReplicationCursor(ReplicationCursorReq) returns (ReplicationCursorRes);
rpc SendCompleted(SendCompletedReq) returns (SendCompletedRes);
rpc HintMostRecentCommonAncestor(HintMostRecentCommonAncestorReq) returns (HintMostRecentCommonAncestorRes);
// for Send and Recv, see package rpc
}
message ListFilesystemReq {}
message ListFilesystemRes { repeated Filesystem Filesystems = 1; }
message Filesystem {
string Path = 1;
string ResumeToken = 2;
bool IsPlaceholder = 3;
bool IsEncrypted = 4;
}
message ListFilesystemVersionsReq { string Filesystem = 1; }
message ListFilesystemVersionsRes { repeated FilesystemVersion Versions = 1; }
message FilesystemVersion {
enum VersionType {
Snapshot = 0;
Bookmark = 1;
}
VersionType Type = 1;
string Name = 2;
uint64 Guid = 3;
uint64 CreateTXG = 4;
string Creation = 5; // RFC 3339
}
enum Tri {
DontCare = 0;
False = 1;
True = 2;
}
message SendReq {
string Filesystem = 1;
// May be empty / null to request a full transfer of To
FilesystemVersion From = 2;
FilesystemVersion To = 3;
// If ResumeToken is not empty, the resume token that CAN be used for 'zfs
// send' by the sender. The sender MUST indicate use of ResumeToken in the
// reply message SendRes.UsedResumeToken If it does not work, the sender
// SHOULD clear the resume token on their side and use From and To instead If
// ResumeToken is not empty, the GUIDs of From and To MUST correspond to those
// encoded in the ResumeToken. Otherwise, the Sender MUST return an error.
string ResumeToken = 4;
Tri Encrypted = 5;
bool DryRun = 6;
}
message Property {
string Name = 1;
string Value = 2;
}
message SendRes {
// Whether the resume token provided in the request has been used or not.
// If the SendReq.ResumeToken == "", this field has no meaning.
bool UsedResumeToken = 2;
// Expected stream size determined by dry run, not exact.
// 0 indicates that for the given SendReq, no size estimate could be made.
int64 ExpectedSize = 3;
repeated Property Properties = 4;
}
message SendCompletedReq {
SendReq OriginalReq = 2;
}
message SendCompletedRes {}
message ReceiveReq {
string Filesystem = 1;
FilesystemVersion To = 2;
// If true, the receiver should clear the resume token before perfoming the
// zfs recv of the stream in the request
bool ClearResumeToken = 3;
}
message ReceiveRes {}
message DestroySnapshotsReq {
string Filesystem = 1;
// Path to filesystem, snapshot or bookmark to be destroyed
repeated FilesystemVersion Snapshots = 2;
}
message DestroySnapshotRes {
FilesystemVersion Snapshot = 1;
string Error = 2;
}
message DestroySnapshotsRes { repeated DestroySnapshotRes Results = 1; }
message ReplicationCursorReq { string Filesystem = 1; }
message ReplicationCursorRes {
oneof Result {
uint64 Guid = 1;
bool Notexist = 2;
}
}
message PingReq { string Message = 1; }
message PingRes {
// Echo must be PingReq.Message
string Echo = 1;
}
message HintMostRecentCommonAncestorReq {
string Filesystem = 1;
FilesystemVersion SenderVersion = 2;
}
message HintMostRecentCommonAncestorRes {}