Simplify cluster startup for scripting and deployment

[corylanou]

This PR will allow the specifying of the meta nodes with the -join argument. It will require that you specify all current nodes for restart. These arguments no longer need to change between restarts.

Example of starting a 3 node meta/data cluster:

# node 1
influxd -config ~/influx1.toml -join localhost:8191,localhost:8291,localhost8391

# node 2
influxd -config ~/influx2.toml -join localhost:8191,localhost:8291,localhost8391

# node 3
influxd -config ~/influx3.toml -join localhost:8191,localhost:8291,localhost8391

Will result in this server configuration:

> show servers
name: data_nodes
----------------
id      http_addr       tcp_addr
3       localhost:8186  localhost:8188
4       localhost:8286  localhost:8288
6       localhost:8386  localhost:8388


name: meta_nodes
----------------
id      http_addr       tcp_addr
1       localhost:8291  localhost:8288
2       localhost:8191  localhost:8188
5       localhost:8391  localhost:8388

This has also been tested with bringing up a cluster, and then having a new node join.

# node 1
influxd -config ~/influx1.toml -join localhost:8191,localhost:8291

# node 2
influxd -config ~/influx2.toml -join localhost:8191,localhost:8291

Wait for the cluster to be healthy:

> show servers
name: data_nodes
----------------
id      http_addr       tcp_addr
3       localhost:8186  localhost:8188
4       localhost:8286  localhost:8288


name: meta_nodes
----------------
id      http_addr       tcp_addr
1       localhost:8291  localhost:8288
2       localhost:8191  localhost:8188

Join new node. Notice you need to specify all nodes in the -join argument

# node 3
influxd -config ~/influx3.toml -join localhost:8191,localhost:8291,localhost8391

Also, to restart nodes 1 and 2, you now need to pass all three nodes. This is typically done via scripted automation.

[e-dard]

Not sure if this is preferable or not, but an alternative to the break/continue stuff could be:

    n, err := s.MetaClient.CreateDataNode(s.httpAPIAddr, s.tcpAddr)
    for ; err != nil; n, err = s.MetaClient.CreateDataNode(s.httpAPIAddr, s.tcpAddr) {
        log.Printf("Unable to create data node. retry in 1s: %s", err.Error())
        time.Sleep(time.Second)
    }
    s.Node.ID = n.ID

or even:

    n, err := s.MetaClient.CreateDataNode(s.httpAPIAddr, s.tcpAddr)
    for err != nil {
        log.Printf("Unable to create data node. retry in 1s: %s", err.Error())
        time.Sleep(time.Second)
        n, err = s.MetaClient.CreateDataNode(s.httpAPIAddr, s.tcpAddr)
    }
    s.Node.ID = n.ID

[jwilder]

👍 Maybe squash the WIP commit of mine though?

[e-dard]

LGTM 👍