Improve documentation to include JNA configuration capabilities

[steghio]

Hi all,

testcontainers appears to be using JNA to perform its magic. By default, JNA writes to /tmp/jna folder and tries to execute something from there.

On some environments, /tmp folder is mounted with noexec flag, which makes the whole process fail.

Could you please add a documentation section where you specify your usage of JNA (maybe it's coming from docker-java?) and adding a note that properties jna.tmpdir and java.io.tmpdir can be used to override the default value?

A sample error that might occur during build with wrong configuration is:

ERROR o.t.d.EnvironmentAndSystemPropertyClientProviderStrategy.test - ping failed with configuration Environment variables, system properties and defaults. Resolved: 
[08:35:13][Step 2/5]     dockerHost=unix:///var/run/docker.sock
[08:35:13][Step 2/5]     apiVersion='{UNKNOWN_VERSION}'
[08:35:13][Step 2/5]     registryUrl='https://index.docker.io/v1/'
[08:35:13][Step 2/5]     registryUsername='xxx'
[08:35:13][Step 2/5]     registryPassword='null'
[08:35:13][Step 2/5]     registryEmail='null'
[08:35:13][Step 2/5]     dockerConfig='DefaultDockerClientConfig[dockerHost=unix:///var/run/docker.sock,registryUsername=xxx,registryPassword=<null>,registryEmail=<null>,registryUrl=https://index.docker.io/v1/,dockerConfigPath=/home/xxx/.docker,sslConfig=<null>,apiVersion={UNKNOWN_VERSION},dockerConfig=<null>]'
[08:35:13][Step 2/5]  due to java.lang.RuntimeException: java.lang.UnsatisfiedLinkError: /tmp/jna-100295547/jna9104525941980512569.tmp: /tmp/jna-100295547/jna9104525941980512569.tmp: failed to map segment from shared object: Operation not permitted
[08:35:13][Step 2/5] 	at org.rnorth.ducttape.timeouts.Timeouts.callFuture(Timeouts.java:68)

And I understand it is not directly your issue, but having a documentation section about it would help others in the future

Thanks and cheers

[rnorth]

Thanks @steghio, and sorry that you hit an issue. I think that a documentation update might be a good thing to do, but I think we should discuss exactly where this would fit into the docs first - we might need a new page, or it might be able to go into the system requirements section somewhere.

[steghio]

Hello,

sure thanks. I could create a PR but I would please ask for directions regarding where to place this information. It is simply a paragraph saying you use JNA and those two properties are available to configure it in the end.

Cheers

[maxotov]

@steghio Hello! I have same issue too. Can you tell me, please, how to override this parameters jna.tmpdir and java.io.tmpdir from testcontainers?
I try this, but not override default values:
export JAVA_OPTS="-Djna.tmpdir=/some-tmp -Djava.io.tmpdir=/some-tmp"

[steghio]

@maxotov

export JAVA_OPTS="-Djna.tmpdir=/some-tmp -Djava.io.tmpdir=/some-tmp"

is not guaranteed to work, it is not exactly the same as directly passing -Djna.tmpdir=/some-tmp -Djava.io.tmpdir=/some-tmp as additional parameters to whatever process you are running.

The reason for this, is that it depends on the JVM and application/processes you are running, whether they actually check for that variable and set those values. For example check this SO question

In my case I directly set those values as parameters in the command that would execute testcontainers and it works. I think you can try the same.

Cheers

[Abdul-Rafy2005]

Hi! I'd like to work on this issue. If it's still relevant, I'll prepare a documentation update covering the JNA configuration and the jna.tmpdir / java.io.tmpdir properties.