gs_sshexkey

Background

During the MogDB installation, you need to perform operations such as running commands and transferring files between hosts in MogDB. Establish mutual trust among the hosts before the installation. gs_sshexkey, provided by MogDB, is used to establish such relationships.

NOTICE:

The mutual trust between users root may incur security risks. You are advised to delete the mutual trust between users root after the installation is complete.

For security purposes, this tool will be automatically deleted after the preinstallation is complete in enterprise-edition installation mode.

After the mutual trust relationship is established using gs_sshexkey, the gaussdb_tmp directory is generated in the user directory. This directory is used to store the ssh-agent process file gauss_socket_tmp and the passphrase file for encrypting the private key (a 32-bit passphrase is randomly generated and encrypted using the encrypt tool). At the same time, two ssh-agent processes are started. These processes are used to mount the private key and automatically enter the corresponding passphrase. After the processes are started, the environment variables of the source user are required for the mutual trust function to take effect.

Prerequisites

The SSH service has been enabled.
You have verified that SSH ports will not be disabled by firewalls.
Each host name and IP address have been correctly configured in the XML file.
Communication among all the hosts is normal.
If the mutual trust is to be established for common users, the same user needs to be created and password set on each host.
Before running commands, check whether all cluster nodes support the expect command. If not, download the expect tool. The expect version 5.45 is recommended.
If the SELinux service is installed and has been started on each host, ensure that the security context of the /root directory is set to the default value system_u:object_r:home_root_t:s0 and that of the /home directory is set to the default value system_u:object_r:admin_home_t:s0, or disable the SELinux service.

To check the SELinux status, run the getenforce command. If the command output is Enforcing, SELinux is installed and has been enabled.

To check the security contexts of the directories, run the following commands:
```
ls -ldZ  /root | awk '{print $4}'
```
```
ls -ldZ  /home | awk '{print $4}'
```
To restore the security contexts of the directories, run the following commands:
```
restorecon -r -vv /home/
```
```
restorecon -r -vv /root/
```

Syntax

Establish mutual trust.

gs_sshexkey -f HOSTFILE  [...] [--skip-hostname-set] [-l LOGFILE]

Display help information.
```
gs_sshexkey -? | --help
```
Display version information.
```
gs_sshexkey -V | --version
```

Parameter Description

-f

Lists the IP addresses of all the hosts among which mutual trust relationships need to be established.

NOTE: You need to ensure that only IP addresses (one in each row) are configured in the hostfile file.
-l

Specifies the path for saving log files.

Value range: existing, accessible absolute paths
--skip-hostname-set

Specifies whether to write the mapping relationship between the host name and IP address of the -f parameter file to the /etc/hosts file. By default, the relationship is written to the file. If this parameter is specified, the relationship is not written to the file.
-?, --help

Displays help information.
-V, --version

Displays version information.

Example

The following examples describe how to establish mutual trust relationships for user root. Passwords can be entered only in interactive mode.

In interactive mode, if the user passwords are the same, run the following commands to establish mutual trust:

gs_sshexkey -f /opt/software/hostfile
Please enter password for current user[root].
Password:
Checking network information.
All nodes in the network are Normal.
Successfully checked network information.
Creating SSH trust.
Creating the local key file.
Appending local ID to authorized_keys.
Successfully appended local ID to authorized_keys.
Updating the known_hosts file.
Successfully updated the known_hosts file.
Appending authorized_key on the remote node.
Successfully appended authorized_key on all remote node.
Checking common authentication file content.
Successfully checked common authentication content.
Distributing SSH trust file to all node.
Successfully distributed SSH trust file to all node.
Verifying SSH trust on all hosts.
Successfully verified SSH trust on all hosts.
Successfully created SSH trust.

Issue