Allow disabling bootstrap checks explicitly

[giftig]

When running elasticsearch in docker, in a development environment or when running builds, I need to have elasticsearch bind to 0.0.0.0 and/or publish a container hostname. This has the undesirable side-effect of enforcing bootstrap checks.

I understand the benefit of these bootstrap checks in production, but I question the assumption that you must be in production if you're binding to a non-local address, especially given the prevalence of docker. Having to modify the host to set vm.max_map_count, for example, severely limits the portability of my test environment for no real reason. It would be useful to be able to set a configuration setting explicitly indicating I am not in production and that the bootstrap checks are therefore unnecessary, rather than binding the assumption of development vs production to the hostname to which we choose to bind.

[dadoonet]

Duplicate of #21655

[jasontedor]

We have added a new discovery type suitable for binding transport to an external interface for the purpose of testing the transport client against Elasticsearch in situations where might not have permissions to modify the configuration of the host to pass the bootstrap checks (for example, CI providers). To summarize the situation:

• we have added a new discovery type called single-node
• when a node uses the discovery type single-node it can not form a cluster with another node
• when a node uses the discovery type single-node the bootstrap checks are disabled
• for users that are running a node using discovery type single-node in production, they should enable the system property es.enable.bootstrap.checks to force the bootstrap checks to run; they are at their own risk if they do not do this

This is documented in the bootstrap checks docs.

This will be available starting with Elasticsearch 5.4.0.

Relates #23585, relates #23595, relates #23598

[ebuildy]

That mean we cannot test clustering in our laptop? not really clever, why not an explicit way to disable it?

[jasontedor]

That mean we cannot test clustering in our laptop?

Why not? You can still form a cluster with nodes that bind to localhost on your laptop.

[chitraj8]

I am trying to setup ES 5.6 with single node, but the startup process fails due to boostrap checks.
how to disable them?

[ebuildy]

@chitraj8 please read what @jaalcorn just said with the single-node (or use the forum for questions).

[DjangoFR]

@jasontedor i think what @ebuildy means is "We cannot test clustering in our docker (one container per es-node)? To be able to simulate a cluster locally in development. And there it would be nice to have a way to explicit disable boostrap checks. Or what is the best way to get it working in docker?

[C-Duv]

To make Elasticsearch API available to Docker containers while still only-binding Elasticsearch to localhost network interface (to avoid Elasticsearch enforcing bootstrap checks), I use redir:

redir \
    --laddr $(ip -4 addr show docker0 | grep "inet\b" | awk '{print $2}' | cut -d '/' -f 1) \
    --lport 9201 \
    --caddr 127.0.0.1 \
    --cport 9200

Then I can use:

docker_host_ip=$( \
    ip route get 255.255.255.254 \
    | head -n 1 \
    | sed -E 's/^[\.0-9]{7,15} via ([\.0-9]{7,15}) dev .*$/\1/' \
)
curl http://${docker_host_ip}:9201

to access Elasticsearch API from within my Docker containers.