Closes#43990. Describe how to change the default GC settings without changing
the default `jvm.options`. Give examples using `jvm.options.d`, and
`ES_JAVA_OPTS` with Docker.
The introductory sections of the reference manual contains some simplified
instructions for adding a node to the cluster. Unfortunately they are a little
too simplified and only really work for clusters running on `localhost`. If you
try and follow these instructions for a distributed cluster then the new node
will, confusingly, auto-bootstrap itself into a distinct one-node cluster.
Multiple nodes running on localhost is a valid config, of course, but we should
spell out that these instructions are really only for experimentation and that
it takes a bit more work to add nodes to a distributed cluster. This commit
does so.
Also, the "important config" instructions for discovery say that you MUST set
`discovery.seed_hosts` whereas in fact it is fine to ignore this setting and
use a dynamic discovery mechanism instead. This commit weakens this statement
and links to the docs for dynamic discovery mechanisms.
Finally, this section is also overloaded with some technical details that are
not important for this context and are adequately covered elsewhere, and
completely fails to note that the default discovery port is 9300. This commit
addresses this.
This commit introduces the ability to override JVM options by adding
custom JVM options files to a jvm.options.d directory. This simplifies
administration of Elasticsearch by not requiring administrators to keep
the root jvm.options file in sync with changes that we make to the root
jvm.options file. Instead, they are not expected to modify this file but
instead supply their own in jvm.options.d. In Docker installations, this
means they can bind mount this directory in. In future versions of
Elasticsearch, we can consider removing the root jvm.options file
(instead, providing all options there as system JVM options).
Clarifies not to set `cluster.initial_master_nodes` on nodes that are joining
an existing cluster.
Co-Authored-By: James Rodewig <james.rodewig@elastic.co>
Removes the suggestion to use IP addresses for `cluster.initial_master_nodes`
in the "important settings" discovery docs, leaving only the suggestion to use
node names.
Relates #41179, #41569
This commit slightly reworks the recommendations in the docs about setting the
heap size:
* the "rules of thumb" are actually instructions that should be followed
* the reason for setting `Xmx` to 50% of the heap size is more subtle than just
leaving space for the filesystem cache
* it is normal to see Elasticsearch using more memory than `Xmx`
* replace `cutoff` and `limit` with `threshold` since all three terms are used
interchangeably
* since we recommend setting `Xmx` equal to `Xms`, avoid talking about setting
`Xmx` in isolation
Relates #41954
In cases where node names and transport addresses can be muddled, it is unclear
that `cluster.initial_master_nodes: master-a:9300` means to look for a node
called `master-a:9300` rather than a node called `master-a` with transport port
`9300`. This commit adds docs to that effect.
The following phrase causes confusion:
> Alternatively the IP addresses or hostnames (if node name defaults to the
> host name) can be used.
This change clarifies the conditions under which you can use a hostname, and
adds an anchor to the note introduced in (#41137) so we can link directly to it
in conversations with users.
This commit changes the note in docs about required java version to note
the existence of the bundled jdk and how to bring your own java. It also
reorganizes the zip/targz docs as zip is no longer suitable on
Linux/MacOS.
In #38333 and #38350 we moved away from the `discovery.zen` settings namespace
since these settings have an effect even though Zen Discovery itself is being
phased out. This change aligns the documentation and the names of related
classes and methods with the newly-introduced naming conventions.
Renames the following settings to remove the mention of `zen` in their names:
- `discovery.zen.hosts_provider` -> `discovery.seed_providers`
- `discovery.zen.ping.unicast.concurrent_connects` -> `discovery.seed_resolver.max_concurrent_resolvers`
- `discovery.zen.ping.unicast.hosts.resolve_timeout` -> `discovery.seed_resolver.timeout`
- `discovery.zen.ping.unicast.hosts` -> `discovery.seed_addresses`
This commit overhauls the documentation of discovery and cluster coordination,
removing mention of the Zen Discovery module and replacing it with docs for the
new cluster coordination mechanism introduced in 7.0.
Relates #32006
This is related to #36652. In 7.0 we plan to deprecate a number of
settings that make reference to the concept of a tcp transport. We
mostly just have a single transport type now (based on tcp). Settings
should only reference tcp if they are referring to socket options. This
commit updates the settings in the docs. And removes string usages of
the old settings. Additionally it adds a missing remote compress setting
to the docs.
Changes the default of the `node.name` setting to the hostname of the
machine on which Elasticsearch is running. Previously it was the first 8
characters of the node id. This had the advantage of producing a unique
name even when the node name isn't configured but the disadvantage of
being unrecognizable and not being available until fairly late in the
startup process. Of particular interest is that it isn't available until
after logging is configured. This forces us to use a volatile read
whenever we add the node name to the log.
Using the hostname is available immediately on startup and is generally
recognizable but has the disadvantage of not being unique when run on
machines that don't set their hostname or when multiple elasticsearch
processes are run on the same host. I believe that, taken together, it
is better to default to the hostname.
1. Running multiple copies of Elasticsearch on the same node is a fairly
advanced feature. We do it all the as part of the elasticsearch build
for testing but we make sure to set the node name then.
2. That the node.name defaults to some flavor of "localhost" on an
unconfigured box feels like it isn't going to come up too much in
production. I expect most production deployments to at least set the
hostname.
As a bonus, production deployments need no longer set the node name in
most cases. At least in my experience most folks set it to the hostname
anyway.
The docs here incorrectly state that it is okay for a heap dump file to
exist when heap dump path is configured to a fixed filename. This is
incorrect, the JVM will fail to write the heap dump if a heap dump file
already exists at the specified location (see the DumpWriter constructor
DumpWriter::DumpWriter(const char* path) in the JVM source).
On some Linux distributions tmpfiles.d cleans files and
directories under /tmp if they haven't been accessed for
10 days.
This can cause problems for ML as ML is currently the only
component that uses the temp directory more than a few
seconds after startup. If you didn't open an ML job for
10 days and then tried to open one then the temp directory
would have been deleted.
This commit prevents the problem occurring in the case of
Elasticsearch being managed by systemd, as systemd private
temp directories are not subject to periodic cleanup (by
default).
Additionally there are now some docs to warn people about
the risk and suggest a manual mitigation for .tar.gz users.
This is a follow up to a previous change which set the error file path
for the package distributions. The observation here is that we always
set the working directory of Elasticsearch to the root of the
installation (i.e., Elasticsearch home). Therefore, we can specify the
error file path relative to this directory and default it to the logs
directory, similar to the package distributions.
This is a follow up to a previous change which set the heap dump path
for the package distributions. The observation here is that we always
set the working directory of Elasticsearch to to the root of
installation (i.e., Elasticsearch home). Therefore, we can specify the
heap dump path relative to this directory and default it to the data
directory, similar to the package distributions.
This commit reorganizes some of the content in the configuring
Elasticsearch section of the docs. The changes are:
- move JVM options out of system configuration into configuring
Elasticsearch
- move JVM options to its own page of the docs
- move configuring the heap to important Elasticsearch settings
- move configuring the heap to its own page of the docs
- move all important settings to individual pages in the docs
- remove bootstrap.memory_lock from important settings, this is covered
in the swap section of system configuration
Relates #27755
James Rodewig
Rory Hunter
David Turner
Jason Tedor
David Turner
Ryan Ernst
Luca Cavanna
Lisa Cawley
Tim Brooks
Nik Everett
datosh
David Roberts
simonzheng
Andrew Banchich