Pods failing because of an environment variable

[pkaramol (Pantelis Karamolegkos)]

I am spinning up an ECK-based cluster. I haven't set any secureSettings but I had forgotten and set an environment variable named gcs.client.default.credentials_file

The pod fails to start with this error

"Caused by: java.lang.IllegalArgumentException: Setting [gcs.client.default.credentials_file] is a secure setting and must be stored inside the Elasticsearch keystore, but was found inside elasticsearch.yml",
"at org.elasticsearch.common.settings.SecureSetting.get(SecureSetting.java:81) ~[elasticsearch-7.16.2.jar:7.16.2]",
"at org.elasticsearch.common.settings.AbstractScopedSettings.validate(AbstractScopedSettings.java:598) ~[elasticsearch-7.16.2.jar:7.16.2]",
"at org.elasticsearch.common.settings.AbstractScopedSettings.validate(AbstractScopedSettings.java:507) ~[elasticsearch-7.16.2.jar:7.16.2]",
"at org.elasticsearch.common.settings.AbstractScopedSettings.validate(AbstractScopedSettings.java:477) ~[elasticsearch-7.16.2.jar:7.16.2]",
"at org.elasticsearch.common.settings.AbstractScopedSettings.validate(AbstractScopedSettings.java:447) ~[elasticsearch-7.16.2.jar:7.16.2]",
"at org.elasticsearch.common.settings.SettingsModule.<init>(SettingsModule.java:137) ~[elasticsearch-7.16.2.jar:7.16.2]",
"at org.elasticsearch.node.Node.<init>(Node.java:500) ~[elasticsearch-7.16.2.jar:7.16.2]",

Why is that? I have not set anything specific to elasticsearch.yml

Why the mere existence of this env var bothers it?

If I remove the env var, everything seems to work.

[legoguy1000 (Alex)]

Because the env settings are injected into the Elasticsearch.yml configuration startup.

[pkaramol (Pantelis Karamolegkos)]

So it automatically recognises any env var with that particular name?

Asking cause I could find this in the source code.

[legoguy1000 (Alex)]

I can't tell u the exact logic. Is refer y to the docs