The request can still time out because we have set dial timeout and
read/write timeout. It increases timeout expectation from 1s to 5s,
but it makes it workable in globally-deployer cluster.
Before this PR, the timeout caused by leader election returns:
```
14:45:37 etcd2 | 2015-08-12 14:45:37.786349 E | etcdhttp: got unexpected
response error (etcdserver: request timed out)
```
After this PR:
```
15:52:54 etcd1 | 2015-08-12 15:52:54.389523 E | etcdhttp: etcdserver:
request timed out, possibly due to leader down
```
It uses heartbeat interval and election timeout to estimate the
expected request timeout.
This PR helps etcd survive under high roundtrip-time environment,
e.g., globally-deployed cluster.
It uses heartbeat interval and election timeout to estimate the
commit timeout for internal requests.
This PR helps etcd survive under high roundtrip-time environment,
e.g., globally-deployed cluster.
Follow the simple rule in the atomic package:
"On both ARM and x86-32, it is the caller's responsibility to arrange
for 64-bit alignment of 64-bit words accessed atomically. The first word
in a global variable or in an allocated struct or slice can be relied
upon to be 64-bit aligned."
Tested on a system with /proc/cpuinfo reporting:
processor : 0
model name : ARMv7 Processor rev 1 (v7l)
Features : swp half thumb fastmult vfp edsp thumbee neon vfpv3
tls vfpv4 idiva idivt vfpd32 lpae evtstrm
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xc0d
CPU revision : 1
The behavior accelarates the happen of the first-time leader election,
so the cluster could elect its leader fast. Technically, it could
help to reduce `electionMs - heartbeatMs` wait time for the first leader election.
Main usage:
1. Quick start for the local cluster when setting a little longer
election timeout
2. Quick start for the global cluster, which sets election timeout to
its maximum 50s.
PUT on the endpoint sets the GlobalDebugLevel to json level value.
The action overwrites the origianl log level setting from
users. We need to write doc to warn this.
