Gamelift 5.1.1 on Linux server crash

Question

When trying to start Unreal Engine Linux server, the server crash with `libcrypto.so.3!UnknownFunction`
This happens on local and remote fleets.

Unreal Engine version 5.2.1 (source)
AWS SDK version 5.1.1
Binaries compiled successfully for Win64 and Linux - **Win64 is working**, **Linux isn't**.

Linux System I used to compile the SDK binaries and run the server:
Ubuntu 22.04.2LTS
OpenSSL 3.0.2 15 Mar 2022
`libcrypto.so.3` and `libssl.so.3` are with the server.

There are no docs on how to compile for Linux so I used this video as info: https://youtu.be/BEfow18dvCA?si=JU5t_P2enVcxkQjI
Also, the [actual docs](https://docs.aws.amazon.com/gamelift/latest/developerguide/integration-engines-setup-unreal.html) for the windows version containing errors in the code example. extra bracket in:

```
 //The Host/compute-name of the GameLift Anywhere instance.
    if (FParse::Value(FCommandLine::Get(), TEXT("-hostid="), serverParameters.m_hostId))
**]**    {
        UE_LOG(GameServerLog, Log, TEXT("HOST_ID: %s"), *serverParameters.m_hostId)
    }
```
and `GetCurrentProcessId()` will not compile for Linux, you will need to change that to `FGenericPlatformProcess::GetCurrentProcessId()`

```
//The PID of the running process
serverParameters.m_processId = FString::Printf(TEXT("%d"), GetCurrentProcessId());
```

Any help on how to get this working for Linux or ideas on what can be the problem source will be extremely valuable for us.
Thank you!

Answer

Hey YogevN,

For C++ SDK without using Unreal, you can just have the .so files with the Server executable. But with Unreal Engine you need to build the C++ SDK using the same version of OpenSSL that was used by Unreal Engine. UE5.1 uses OpenSSL1.1.n, but if you're on a different version you can double-check the version of OpenSSL by looking for the following log line from the UE packaging output window: "LogInit:  - supports SSL with OpenSSL/1.1.1n".

Then, download the same version of OpenSSL from https://www.openssl.org/source/old/1.1.1/

```
$ cd ~/openssl-1.1.1n; ./config; make
$ mkdir lib
$ cp libcrypto.so.1.1 libssl.so.1.1 lib/
$ cd ~/GameLift-Cpp-ServerSDK-5.1.0/; mkdir out
$ export OPENSSL_ROOT_DIR=/home/ec2-user/openssl-1.1.1n/
$ export OPENSSL_LIBRARIES=/home/ec2-user/openssl-1.1.1n/lib/
$ cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -S . -B ./out -DBUILD_FOR_UNREAL=1
$ cd out; make
```

Place the generated `libaws-cpp-sdk-gamelift-server.so` in `\Plugins\GameLiftServerSDK\ThirdParty\GameLiftServerSDK\Linux\x86_64-unknown-linux-gnu`. This is where Unreal links to the C++ SDK from during compilation and packaging. Detailed instructions on setting up the plugin can be found [here](https://docs.aws.amazon.com/gamelift/latest/developerguide/integration-engines-setup-unreal.html).

After packaging the game server for Linux, copy over the .so files for OpenSSL into the package bundle. Your folder structure should finally look like:

```
-
--install.sh
--.sh (This is the target .sh file that is generated by Unreal itself)
--\Plugins\GameLiftServerSDK\ThirdParty\GameLiftServerSDK\Linux\x86_64-unknown-linux-gnu\
   --libaws-cpp-sdk-gamelift-server.so
   --libcrypto.so.1.1
   --libssl.so.1.1
```

Gamelift 5.1.1 on Linux server crash

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