Motivation:
- ServerConfig is part of 'embed' public API, while etcdserver is more 'internal'
- EtcdServer is already too big and config is pretty wide-spread leaf
if we were to split etcdserver (e.g. into pre & post-apply part).
The flag protects etcd memory from being swapped out to disk.
This can happen in memory constrained systems where mmaped bbolt
area is natural condidate for swapping out.
This flag should provide better tail latency on the cost of higher RSS
ram usage. If the experiment is successful, the logic should get moved
into bbolt layer, where we can protect specific bbolt instances
(e.g. avoid protecting both during defragmentation).
When we have an external component that checks /health periodically, the
etcd server logs can be quite verbose (e.g., DDOS-ing against insure
etcd health check can lead to disk space full due to large log files).
This change was introduced in #11704.
While we keep the warning logs for etcd health check failures, the
success (or OK) log level should be set to DEBUG.
Fixes#12676
Example:
https://travis-ci.com/github/etcd-io/etcd/jobs/470404938
```
% (cd server && go vet ./...)
stderr: # go.etcd.io/etcd/server/v3/etcdserver/api/v2store
stderr: etcdserver/api/v2store/node_extern_test.go:107:9: possible misuse of reflect.SliceHeader
stderr: etcdserver/api/v2store/node_extern_test.go:107:16: possible misuse of reflect.SliceHeader
```
In these unit tests, goroutines may leak if certain branches are chosen. This commit edits channel operations and buffer sizes, so no matter what branch is chosen, the test will end correctly. This commit doesn't change the semantics of unit tests.
Before this patch, a client which cancels the context for a watch results in the
server generating a `rpctypes.ErrGRPCNoLeader` error that leads the recording of
a gRPC `Unavailable` metric in association with the client watch cancellation.
The metric looks like this:
grpc_server_handled_total{grpc_code="Unavailable",grpc_method="Watch",grpc_service="etcdserverpb.Watch",grpc_type="bidi_stream"}
So, the watch server has misidentified the error as a server error and then
propagates the mistake to metrics, leading to a false indicator that the leader
has been lost. This false signal then leads to false alerting.
The commit 9c103dd0dedfc723cd4f33b6a5e81343d8a6bae7 introduced an interceptor which wraps
watch streams requiring a leader, causing those streams to be actively canceled
when leader loss is detected.
However, the error handling code assumes all stream context cancellations are
from the interceptor. This assumption is broken when the context was canceled
because of a client stream cancelation.
The core challenge is lack of information conveyed via `context.Context` which
is shared by both the send and receive sides of the stream handling and is
subject to cancellation by all paths (including the gRPC library itself). If any
piece of the system cancels the shared context, there's no way for a context
consumer to understand who cancelled the context or why.
To solve the ambiguity of the stream interceptor code specifically, this patch
introduces a custom context struct which the interceptor uses to expose a custom
error through the context when the interceptor decides to actively cancel a
stream. Now the consuming side can more safely assume a generic context
cancellation can be propagated as a cancellation, and the server generated
leader error is preserved and propagated normally without any special inference.
When a client cancels the stream, there remains a race in the error handling
code between the send and receive goroutines whereby the underlying gRPC error
is lost in the case where the send path returns and is handled first, but this
issue can be taken separately as no matter which paths wins, we can detect a
generic cancellation.
This is a replacement of https://github.com/etcd-io/etcd/pull/11375.
Fixes#10289, #9725, #9576, #9166
* Turn off checking of format of commit message.
* scripts/fix.sh: Fix fixing whitespaces in *.sh scripts
Aparently there is a difference between:
find ./ -print0 -name *.sh and
find ./ -name *.sh -print0
* etcdserver unit tests: Do not call .Fatalf(...) from not test's goroutine.
Fixes following test failures:
https://travis-ci.com/github/etcd-io/etcd/jobs/425920416
```
% (cd server && go vet ./...)
stderr: # go.etcd.io/etcd/server/v3/etcdserver
stderr: etcdserver/server_test.go:1002:4: call to (*T).Fatalf from a non-test goroutine
stderr: etcdserver/server_test.go:1166:4: call to (*T).Fatalf from a non-test goroutine
FAIL: (code:2):
% (cd server && go vet ./...)
FAIL: 'run go vet ./...' checking failed (!=0 return code)
FAIL: 'govet' failed at Tue Nov 3 04:07:47 UTC 2020
```
