If any of this initialization fails, something very bad has happened,
and we should not continue as-is (this has previously manifested in
strange bugs)
etcd checks that the data dir is writable by writing and removing an
empty file to the data dir during startup and exits non-zero if that
fails.
fixes#876
This is a simple solution to having the proxy keep up to date with the
state of the cluster. Basically, it uses the cluster configuration
provided at start up (i.e. with `-initial-cluster-state`) to determine
where to reach peer(s) in the cluster, and then it will periodically hit
the `/members` endpoint of those peer(s) (using the same mechanism that
`-cluster-state=existing` does to initialise) to update the set of valid
client URLs to proxy to.
This does not address discovery (#1376), and it would probably be better
to update the set of proxyURLs dynamically whenever we fetch the new
state of the cluster; but it needs a bit more thinking to have this done
in a clean way with the proxy interface.
Example in Procfile works again.
Removes the notion of name being anything more than advisory or
command-line grouping, and adds checks for bootstrapping the command
line. IDs are consistent if the URLs are consistent.
We use nodeID as the default dir previously. It works fine before we do dynamic nodeID
generation (introducing time). After the change the dynamic nodeID will change every
time we restart the etcd process. If the user does not provide the data dir, the default
dir will change every time. It is not the desired behavior.
In this commit, we change the default data dir to node name. If the user changes the node
name and does provide the data dir, etcd still cannot recover from previous state. But it
is much better than using nodeID. And it is actually a doucmentation issue.
Conflicts:
main.go
In preperation for adding the ability to join a machine to an existing
cluster force the user to specify whether they expect this to me a new
cluster or an active one.
The error for not specifying the initial-cluster-state is:
```
etcd: initial cluster state unset and no wal found
```
