With #19140 we started persisting the node ID across node restarts. Now that we have a "stable" anchor, we can use it to generate a stable default node name and make it easier to track nodes over a restarts. Sadly, this means we will not have those random fun Marvel characters but we feel this is the right tradeoff.
On the implementation side, this requires a bit of juggling because we now need to read the node id from disk before we can log as the node node is part of each log message. The PR move the initialization of NodeEnvironment as high up in the starting sequence as possible, with only one logging message before it to indicate we are initializing. Things look now like this:
```
[2016-07-15 19:38:39,742][INFO ][node ] [_unset_] initializing ...
[2016-07-15 19:38:39,826][INFO ][node ] [aAmiW40] node name set to [aAmiW40] by default. set the [node.name] settings to change it
[2016-07-15 19:38:39,829][INFO ][env ] [aAmiW40] using [1] data paths, mounts [[ /(/dev/disk1)]], net usable_space [5.5gb], net total_space [232.6gb], spins? [unknown], types [hfs]
[2016-07-15 19:38:39,830][INFO ][env ] [aAmiW40] heap size [1.9gb], compressed ordinary object pointers [true]
[2016-07-15 19:38:39,837][INFO ][node ] [aAmiW40] version[5.0.0-alpha5-SNAPSHOT], pid[46048], build[473d3c0/2016-07-15T17:38:06.771Z], OS[Mac OS X/10.11.5/x86_64], JVM[Oracle Corporation/Java HotSpot(TM) 64-Bit Server VM/1.8.0_51/25.51-b03]
[2016-07-15 19:38:40,980][INFO ][plugins ] [aAmiW40] modules [percolator, lang-mustache, lang-painless, reindex, aggs-matrix-stats, lang-expression, ingest-common, lang-groovy, transport-netty], plugins []
[2016-07-15 19:38:43,218][INFO ][node ] [aAmiW40] initialized
```
Needless to say, settings `node.name` explicitly still works as before.
The commit also contains some clean ups to the relationship between Environment, Settings and Plugins. The previous code suggested the path related settings could be changed after the initial Environment was changed. This did not have any effect as the security manager already locked things down.
The setting bootstrap.mlockall is useful on both POSIX-like systems
(POSIX mlockall) and Windows (Win32 VirtualLock). But mlockall is really
a POSIX only thing so the name should not be tied POSIX. This commit
renames the setting to "bootstrap.memory_lock".
Relates #18669
Pascal Borreli
Boaz Leskes
Jason Tedor
Clinton Gormley