Install the Dependencies (by Compiling and Installing the Source Code)

Before using the source code for compilation, install GCC/G++, devtoolset-gcc, Autoconf, and CMake on each node. Table 1 lists the versions.

LLVM must be compiled on CentOS 7.6 so that it can run properly on both OSs. You need to install devtoolset-gcc on CentOS 7.6.
jemalloc compilation has no restrictions on the environment. If jemalloc is compiled on openEuler, GCC/G++ must be installed on openEuler 20.03 LTS SP1.

**Table 1** Software required for source code compilation
Item	Required Version
GCC/G++	7.3.0
devtoolset-gcc	7
Autoconf	2.69
CMake	3.13.4

Installing LLVM

The following operations must be performed on the management node and all compute nodes.

Download https://github.com/llvm/llvm-project/archive/refs/tags/llvmorg-12.0.1.tar.gz, create an /opt/omni-operator directory on the management node and compute nodes as the root directory for deploying OmniOperator, go to the directory, and upload the package to /opt/omni-operator.
```
mkdir /opt/omni-operator
cd /opt/omni-operator
tar zxvf llvm-project-llvmorg-12.0.1.tar.gz
mv llvm-project-llvmorg-12.0.1 llvm
cd llvm
mkdir build
```

Go to the build directory, and compile and install LLVM.

cd ./build
cmake -DCMAKE_INSTALL_PREFIX=/opt/llvm -DCMAKE_BUILD_TYPE=Release -DLLVM_BUILD_LLVM_DYLIB=true -DLLVM_ENABLE_PROJECTS="clang;libcxx;libcxxabi" -G "Unix Makefiles" ../llvm
make -j4
make install

Create a lib directory in /opt/omni-operator and copy /opt/omni-operator/llvm/lib/libLLVM-12.so to /opt/omni-operator/lib.
```
mkdir /opt/omni-operator/lib
cp /opt/omni-operator/llvm/lib/libLLVM-12.so /opt/omni-operator/lib/
```

The /opt/omni-operator, /opt/omni-operator/llvm, and /opt/omni-operator/lib directories can be customized.

Installing jemalloc

The following operations must be performed on the management node and all compute nodes.

Download https://github.com/jemalloc/jemalloc/archive/refs/tags/5.2.1.tar.gz and upload it to the /opt/omni-operator directory of the management node and compute nodes.
```
cd /opt/omni-operator/
tar zxvf jemalloc-5.2.1.tar.gz
mv jemalloc-5.2.1 jemalloc
```
Go to the jemalloc directory, run the script, and install the generated file.
```
cd jemalloc
./autogen.sh --disable-initial-exec-tls
make –j2
```
Copy /opt/omni-operator/jemalloc/lib/libjemalloc.so.2 to the /opt/omni-operator/lib directory.
```
cp /opt/omni-operator/jemalloc/lib/libjemalloc.so.2 /opt/omni-operator/lib/
```

The /opt/omni-operator/jemalloc directory can be customized.

Parent topic: Installing Dependencies