Unable to log in to Plesk on CentOS 7: Failed to initialize NSS library

Symptoms

• Unable to log into Plesk with the following error in browser screen:

  Internal error: Unable to read components configuration from the service node: error: Failed to initialize NSS library Fatal error: plesk::InternalRpmError(Internal RPM error: Failed to initialize NSS library

• Any operation with rpm or yum shows error like below: 

  error: Failed to initialize NSS library
  There was a problem importing one of the Python modules
  required to run yum. The error leading to this problem was:
  cannot import name ts
  Please install a package which provides this module, or
  verify that the module is installed correctly.

• Files from packages nss or nss-util are outdated:

  # rpm -ql nss | grep lib
  /usr/lib64/libnss3.so
  /usr/lib64/libnssckbi.so
  /usr/lib64/libsmime3.so
  /usr/lib64/libssl3.so
  /usr/lib64/nss/libnssckbi.so
  # ls -l /usr/lib64/libssl3.so
  -rwxr-xr-x 1 root root 341024 Feb 16 22:20 /usr/lib64/libssl3.so

  
  

  # rpm -ql nss-util
  /usr/lib64/libnssutil3.so
  # ls -l /usr/lib64/libnssutil3.so
  -rwxr-xr-x 1 root root 194944 Feb 16 06:48 /usr/lib64/libnssutil3.so

  
  

  # ls -l /usr/lib64/libnspr4.so
  -rwxr-xr-x 1 root root 251832 May 16 16:46 /usr/lib64/libnspr4.so

Cause

This behavior is caused by a bug with ID 1477308 in CentOS.

Resolution

1. Connect to the server via SSH.

2. Download packages for the necessary OS version (as an example resolution for CentOS 7.5 is given):

   # wget http://fr2.rpmfind.net/linux/centos/7.5.1804/os/x86_64/Packages/nss-3.34.0-4.el7.x86_64.rpm
   # wget http://fr2.rpmfind.net/linux/centos/7.5.1804/os/x86_64/Packages/nss-util-3.34.0-2.el7.x86_64.rpm

3. Unpack packages:

   # rpm2cpio nss-3.34.0-4.el7.x86_64.rpm | cpio -idmv
   # rpm2cpio nss-util-3.34.0-2.el7.x86_64.rpm | cpio -idmv

4. Create backups of libraries:

   # mkdir /root/pleskbackup/
   # cp /usr/lib64/libnss3.so /root/pleskback/
   # cp /usr/lib64/libsmime3.so /root/pleskback/
   # cp /usr/lib64/libssl3.so /root/pleskback/
   # cp /usr/lib64/nss/libnssckbi.so /root/pleskback/
   # cp /usr/lib64/libnssutil3.so /root/pleskback

5. Replace libraries:

   # cp /root/plesktest/usr/lib64/libnss3.so /usr/lib64/libnss3.so
   # cp /root/plesktest/usr/lib64/libsmime3.so /usr/lib64/libsmime3.so
   # cp /root/plesktest/usr/lib64/libssl3.so /usr/lib64/libssl3.so
   # cp /root/plesktest/usr/lib64/nss/libnssckbi.so /usr/lib64/nss/libnssckbi.so
   # cp /root/plesktest/usr/lib64/libnssutil3.so /usr/lib64/libnssutil3.so

6. Restart services:

   # service sw-engine restart
   # service sw-cp-server restart
   # service httpd restart
   # service nginx restart