Logging In to a Non-Cluster Node Using a Cluster User in Normal Mode

Scenario

When the cluster is installed in normal mode, the component clients do not support Kerberos authentication and cannot use the kinit command. Therefore, nodes outside the cluster cannot use users in the cluster by default. This may result in a user authentication failure when one of these nodes access a component server.

The node administrator can configure a user who has the same name as that of a user for a node outside the cluster, allow the user to log in to the node using the SSH protocol, and connect to the servers of components in the cluster by using the user who logs in to the OS.

Prerequisites

• The node outside the cluster can connect to the cluster service plane.
• The KrbServer service of the cluster is running properly.
• You have obtained the password of user root of the node outside the cluster.
• A Human-machine user has been planned and added to the cluster, and you have obtained the authentication credential file. For details, see Creating a User and Exporting an Authentication Credential File.

Procedure

1. Log in to the node where a user is to be added as user root.
2. Run the following commands:

   rpm -qa | grep pam and rpm -qa| grepkrb5-client

   The following RPM packages are displayed:

   pam_krb5-32bit-2.3.1-47.12.1 
   pam-modules-32bit-11-1.22.1 
   yast2-pam-2.17.3-0.5.211 
   pam-32bit-1.1.5-0.10.17 
   pam_mount-32bit-0.47-13.16.1 
   pam-config-0.79-2.5.58 
   pam_krb5-2.3.1-47.12.1 
   pam-doc-1.1.5-0.10.17 
   pam-modules-11-1.22.1 
   pam_mount-0.47-13.16.1 
   pam_ldap-184-147.20 
   pam-1.1.5-0.10.17 
   krb5-client-1.6.3     

3. Check whether the RPM packages in the list are installed in the OS.
   • If yes, go to 5.
   • If no, go to 4.

4. Obtain the lacked RPM packages from the OS image, upload the files to the current directory, and run the following command to install the RPM packages:

   rpm -ivh *.rpm

   

   The RPM packages to be installed may bring security risks. The risks that may be brought by the installation of these RPM packages must be taken into consideration during OS hardening.

   After the RPM packages are installed, go to 5.

5. Run the following command to configure Kerberos authentication on PAM:

   pam-config --add --krb5

   

   If you need to cancel Kerberos authentication and system user login on a non-cluster node, run the pam-config --delete --krb5 command as user root.

6. Decompress the authentication credential file to obtain krb5.conf, use WinSCP to upload this configuration file to the /etc directory on the node outside the cluster, and run the following command to configure related permission to enable other users to access the file, such as permission 604:

   chmod 604 /etc/krb5.conf

7. Run the following command in the connection session as user root to add the corresponding OS user to the Human-machine user, and specify root as the primary group.

   The OS user password is the same as the initial password when the Human-machine user is created on Manager.

   useradd Username -m-d /home/admin_test -g root -s /bin/bash

   For example, if the name of the Human-machine user is admin_test, run the following command:

   useradd admin_test -m -d /home/admin_test -g root -s /bin/bash

   

   When you use the newly added OS user to log in to the node by using the SSH protocol for the first time, the system prompts that the password has expired after you enter the user password, and the system prompts that the password needs to be changed after you enter the user password again. You need to enter a new password that meets the password complexity requirements of both the node OS and the cluster.