This commit adds a new option for activating profiling based on pprof
in etcd process.
- -enable-pprof: boolean type option which activates profiling
For example, if a client URL is http://localhost:12379, users and
developers access heap profiler with this URL:
http://localhost:12379/debug/pprof/heap
Basic support for lease operations like create and revoke.
We still need to:
1. attach keys to leases in KV implmentation if lease field is set
2. leader periodically removes expired leases
3. leader serves keepAlive requests and follower forwards keepAlive
requests to leader.
go HTTP library uses type assertion to determine if a connection
is a TLS connection. If we wrapper TLS Listener with any customized
Listener that can create customized Conn, HTTPs will be broken.
This commit fixes the issue.
etcd might generate incomplete proxy config file after a power failure.
It is because we use ioutil.WriteFile. And iotuile.WriteFile does
not call Sync before closing the file.
We should wrap the blocking function with a closure. And first
creates a go routine to execute the function. Or the inner function
blocks before creating the go routine.
This moves the code to create listener and roundTripper for raft communication
to the same place, and use explicit functions to build them. This prevents
possible development errors in the future.
rafthttp has different requirements for connections created by the
transport for different usage, and this is hard to achieve when giving
one http.RoundTripper. Pass into pkg the data needed to build transport
now, and let rafthttp build its own transports.
Before this PR, the log is
```
2015/09/1 13:18:31 etcdmain: client: etcd cluster is unavailable or
misconfigured
```
It is quite hard for people to understand what happens.
Now we print out the exact reason for the failure, and explains the way
to handle it.
Current membership changing functionality of etcd seems to have a
problem which can cause deadlock.
How to produce:
1. construct N node cluster
2. add N new nodes with etcdctl member add, without starting the new members
What happens:
After finishing add N nodes, a total number of the cluster becomes 2 *
N and a quorum number of the cluster becomes N + 1. It means
membership change requires at least N + 1 nodes because Raft treats
membership information in its log like other ordinal log append
requests.
Assume the peer URLs of the added nodes are wrong because of miss
operation or bugs in wrapping program which launch etcd. In such a
case, both of adding and removing members are impossible because the
quorum isn't preserved. Of course ordinal requests cannot be
served. The cluster would seem to be deadlock.
Of course, the best practice of adding new nodes is adding one node
and let the node start one by one. However, the effect of this problem
is so serious. I think preventing the problem forcibly would be
valuable.
Solution:
This patch lets etcd forbid adding a new node if the operation changes
quorum and the number of changed quorum is larger than a number of
running nodes. If etcd is launched with a newly added option
-strict-reconfig-check, the checking logic is activated. If the option
isn't passed, default behavior of reconfig is kept.
Fixes https://github.com/coreos/etcd/issues/3477
