While it appears that etcd is not vulnerable to CVE-2021-3121,
it is a good idea to update to the new generator so that new
vulnerable code isn't generated in any future APIs. Also, this
lays the issue to rest of whether there is any issue with
etcd and CVE-2021-3121.
This commit removes the `XXX_NoUnkeyedLiteral`, `XXX_unrecognized`, and
`XXX_sizecache` auto-generated fields from generated protobuf structs in
the raft package. This was done for all of the same reasons CockroachDB
removed the generation of these fields in https://github.com/cockroachdb/cockroach/pull/38404.
They come with very limited advantages but moderate disadvantages.
`XXX_NoUnkeyedLiteral` and `XXX_sizecache` were only enabled recently in
cc7b4fa, and this appears to have been unintentional. Meanwhile,
`XXX_unrecognized` has been around for longer and has arguably more
reason to stay because it can assist with forwards compatibility.
However, any real mixed-version upgrade story for this package is mostly
untold at this point, and keeping this field seems just as likely to
cause unexpected bugs (e.g. a field was propagated but not updated
correctly when passed through an old version) as it seems to fix real
issues, so it also doesn't warrant its cost.
This reduces the in-memory representation size of all Raft protos.
Notably, it reduces the memory size of an `Entry` proto from *80 bytes*
to *48 bytes* and the memory size of a `Message` proto from *392 bytes*
to *264 bytes*. Both of these structs are used frequently, and often in
slices, where this wasted space really starts to add up.
This was motivated by a regression in microbenchmarks in CockroachDB due
to cc7b4fa, which was caught in https://github.com/cockroachdb/cockroach/issues/62212.
The Entry struct has misaligned fields that are accessed atomically. The
misalignment is caused by the EntryType enum which the Protocol Buffers
spec forces to be a 32bit int.
Moving the order of the fields without renumbering them in the .proto file
seems to align the go structure without changing the wire format.
Using Go-style import paths in protos is not idiomatic. Normally, this
detail would be internal to etcd, but the path from which gogoproto
is imported affects downstream consumers (e.g. cockroachdb).
In cockroach, we want to avoid including `$GOPATH/src` in our protoc
include path for various reasons. This patch puts etcd on the same
convention, which allows this for cockroach.
More information: https://github.com/cockroachdb/cockroach/pull/2339#discussion_r38663417
This commit also regenerates all the protos, which seem to have
drifted a tiny bit.
raft relies on the link layer to report the status of the sent snapshot.
If the snapshot is still sending, the replication to that remote peer will
be paused. If the snapshot finish sending, the replication will begin
optimistically after electionTimeout. If the snapshot fails, raft will
try to resend it.
Now that heartbeats are distinct from MsgApp{,Resp}, the retries
currently performed in stepLeader's MsgAppResp section are only
performed on an actual MsgAppResp (or a new MsgProp). This means
that it may take a long time to recover from a dropped MsgAppResp
in a quiet cluster.
This commit adds a dedicated heartbeat response message. This message
does not convey the follower's current log position because the
MsgHeartbeat does not include the leaders term and index. Upon receipt
of a heartbeat response, the leader may retry the latest MsgApp if it
believes the follower to be behind.
Compaction is now treated as an implementation detail of Storage
implementations; Node.Compact() and related functionality have been
removed. Ready.Snapshot is now used only for incoming snapshots.
A return value has been added to ApplyConfChange to allow applications
to track the node information that must be stored in the snapshot.
raftpb.Snapshot has been split into Snapshot and SnapshotMetadata, to
allow the full snapshot data to be read from disk only when needed.
raft.Storage has new methods Snapshot, ApplySnapshot, HardState, and
SetHardState. The Snapshot and HardState parameters have been removed
from RestartNode() and will now be loaded from Storage instead.
The only remaining difference between StartNode and RestartNode is that
the former bootstraps an initial list of Peers.
Users might want to update the peerurl of the etcd member in several cases.
For example, if the IP address of the physical machine etcd running on is
changed, user need to update the adversite-pee-rurl accordingly.
This commit makes etcd support updating the advertise-peer-url of its members.
