Installing the psycopg2 Python package for PostgreSQL-backed Hue

If you are installing Runtime 7 and using PostgreSQL as a backend database for Hue, then you must install the 2.9.3 version of the psycopg2 package on all Hue hosts. The psycopg2 package is automatically installed as a dependency of Cloudera Manager Agent, but the version installed is often lower than 2.9.3.

Cloudera recommends that you install 2.9.5 version of the psycopg2 package on RHEL8 and CentOS 8.

CentOS 7
RHEL 8/CentOS 8
SLES 12
Ubuntu 18 and 20

SSH into the Hue host as a root user.
Install the psycopg2 package dependencies for CentOS 7 by running the following commands:
```
yum install -y centos-release
yum install -y centos-release-scl
yum install -y xmlsec1  xmlsec1-openssl
```
Install the rh-postgresql-postgresql-devel package corresponding to your database version by running the following command:
```
yum install -y rh-postgresql[***DB-VERSION***]-postgresql-devel
```
note
The available versions for the rh-postgresql-postgresql-devel package are rh-postgresql10-postgresql-devel, rh-postgresql12-postgresql-devel, and rh-postgresql13-postgresql-devel which you can use with the corresponding PostgreSQL database versions. If you are running PostgreSQL database of version is 9, 11, or 14, then Cloudera recommends that you use rh-postgresql10-postgresql-devel, rh-postgresql10-postgresql-devel, and rh-postgresql13-postgresql-devel packages respectively.
Add the location of the installed rh-postgresql-postgresql-devel package to the PATH environment variable by running the following command:
```
export PATH=/opt/rh/rh-postgresql[***DB-VERSION***]/root/usr/bin:$PATH
```
Verify the database version by running the following command:
```
psql -V
```
Install the psycopg2 package by running the following command:
```
pip3.8 install psycopg2==2.9.3
```

If you see an error such as ImportError: libpq.so.rh-postgresql10-5: cannot open shared object file: No such file or directory, then add the path where you installed the package to the LD_LIBRARY_PATH environment variable as shown in the following sample command:

export LD_LIBRARY_PATH=/opt/rh/rh-postgresql[***DB-VERSION***]/root/usr/lib64:$LD_LIBRARY_PATH

To install the centos7-extras repo, perform the following steps:

Obtain the release number of the operating system and input it into the OS_RELEASE_MAJOR variable by running the following commands:
```
OS_RELEASE=$(rpm -q --qf "%{VERSION}" $(rpm -q --whatprovides redhat-release))
```
```
OS_RELEASE_MAJOR=$(echo $OS_RELEASE | cut -d. -f1)
```

Download the GPG key and save it locally by running the following command:

curl -s https://www.centos.org/keys/RPM-GPG-KEY-CentOS-$OS_RELEASE_MAJOR | sudo tee /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-$OS_RELEASE_MAJOR

Create the repo file named Centos-Extras.repo in the /etc/yum.repos.d directory by running the following command:
```
vi /etc/yum.repos.d/Centos-Extras.repo
```

Add the following lines in the Centos-Extras.repo file, save the file and exit:

[extras] 
name=CentOS-$releasever - Extras baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/ 
#baseurl=http://mirror.infra.cloudera.com/repos/centos/7/extras/\$basearch/
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
priority=1

The following steps apply to RHEL 8.6 and CentOS 8.4:

SSH into the Hue host as a root user.

Install the psycopg2 package dependencies for RHEL 8/CentOS 8 by running the following commands:

dnf install -y https://download.postgresql.org/pub/repos/yum/reporpms/EL-8-x86_64/pgdg-redhat-repo-latest.noarch.rpm

yum install -y xmlsec1  xmlsec1-openssl

Install the PostgreSQL database server by running the following command:
```
dnf install -y postgresql-server
```
Install the postgresql-devel package by running the following command:
```
dnf install y postgresqlserver-devel
```
Install the psycopg2 package by running the following command:
```
pip3.8 install psycopg2-binary==2.9.5
```

SSH into the Hue host as a root user.
Install the psycopg2 package dependencies for SLES 12 by running the following commands:
```
zypper install xmlsec1
zypper install xmlsec1-devel
Zypper install xmlsec1-openssl-devel
```
Install the postgresql-devel package corresponding to your database version by running the following command:
```
zypper -n postgresql[***DB-VERSION***]-devel
```
Add the location of the installed postgresql-devel package to the PATH environment variable by running the following command:
```
export PATH=$PATH:/usr/local/bin
```
Install the psycopg2 package by running the following command:
```
pip3.8 install psycopg2==2.9.3 --ignore-installed
```

SSH into the Hue host as a root user.
Install the psycopg2 package dependencies for Ubuntu by running the following commands:
```
apt-get install -y xmlsec1
apt-get install libxmlsec1-openssl
apt-get install libpq-dev python3-pip -y
```
Install the python3-dev and libpq-dev packages by running the following command:
```
apt install python3-dev libpq-dev
```
Add the location of the installed postgresql-devel package to the PATH environment variable by running the following command:
```
export PATH=$PATH:/usr/local/bin
```
Install the psycopg2 package by running the following command:
```
pip3.8 install psycopg2==2.9.3 --ignore-installed
```