Using environment variables in readonlyrest.yml (Elasticsearch on Systemd)

#1

Hi there
I’m wanting to use environment variables (CentOS) in my readonlyrest.yml.
It seems that this has been supported in various ways in the past although I can’t get it working at the moment. I am using version 7.16.2.

I have tried the following syntaxes, found in previous support threads:

“${MY_ENV_VAR}”
“${ENV:MY_ENV_VAR}”
“@{env:MY_ENV_VAR}”

But each time it results in an error, e.g.:
“Cannot resolve ENV Variable ‘MY_ENV_VAR’”

Is this still supported and if so what syntax should I use?

Many thanks

#3

Hey there, sorry to bump, but just wondering whether environment variables are currently expected to work as per documentation or are there issues with it?
I thought maybe upgrading to 8.2.2/1.40 would solve the problem but using an environment variable such as ${LDAP_PASS} causes an exception:

uncaught exception in thread [main]
java.lang.IllegalStateException:failed to load plugin class [tech.beshu.ror.es.ReadonlyRestPlugin]
Likely root cause: org.elasticsearch.ElasticsearchException: Invalid ROR SSL configuration. Cannot resolve ENV variable ‘LDAP_PASS’.

Not a big issue, just curious because I’ve been unable to get it to work.

Edit:
Just to confirm (as that would be the obvious next question!), I have created the environment variable:

export LDAP_PASS=myldappass

printenv
> LDAP_PASS=myldappass
#4

Please take a look at the documentation. Here is an example in our tests.

If it doesn’t work, it probably means that JVM process doesn’t see the env (probably sth wrong with exporting)

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#5

For info, in case anyone else has the same problem and comes across this post (this isn’t a ROR problem, but you might find yourself looking here)…

The issue is that if you are running elasticsearch as a service, it doesn’t have access to system environment variables.

To get around this, look in the elasticsearch system service file, something like this (I am running CentOS):
/usr/lib/systemd/system/elasticsearch.service

You will see the line:
EnvironmentFile=/etc/sysconfig/elasticsearch

You can set environment variables for elasticsearch inside that file, i.e. append:
LDAP_PASS=myldappass

Then:

systemctl daemon-reload

Then restart elasticsearch, and the environment variable should be picked up.

2 Likes
#6

Great point @joemo2023, very useful note. Thanks for taking the time to write this for the future googler’s benefit. :+1:

1 Like