The "Restore any snapshots as required" step is a trap: it's somewhere between
tricky and impossible to restore multiple clusters into a single one.
Also add a note about configuring discovery during a rolling upgrade to
proscribe any rare cases where you might accidentally autobootstrap during the
upgrade.
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>
This commit addresses a few more frequently-asked questions:
* clarifies that bootstrapping doesn't happen even after a full cluster
restart.
* removes the example that uses IP addresses, to try and further encourage the
use of node names for bootstrapping.
* clarifies that auto-bootstrapping might form different clusters on different
hosts, and gives a process for starting again if this wasn't what you wanted.
* adds the "do not stop half-or-more of the master-eligible nodes" slogan that
was notably absent.
* reformats one of the console examples to a narrower width
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.
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
David Turner
Yannick Welsch
Lisa Cawley