setup-ssh

sets up an SSH key on specified hosts

Synopsis

asadmin [asadmin-options] setup-ssh [--help]
[--sshport ssh-port] [--sshuser ssh-user]
[--sshkeyfile ssh-keyfile] [--sshpublickeyfile ssh-public-keyfile]
[--generatekey={false|true}]
host-list

Description

The setup-ssh subcommand sets up a secure shell (SSH) key on the hosts that are specified as the operand of the subcommand. This key enables \{product---name} to use public-key authentication for authentication of the user’s SSH login on remote hosts.

SSH ensures that \{product---name} clusters that span multiple hosts can be administered centrally. When a user runs a subcommand for cluster administration that acts on multiple hosts, the subcommand is propagated from the domain administration server (DAS) host to remote hosts. To propagate subcommands that act on a \{product---name} instance that is not running, or on a node where no instances are running, \{product---name} uses SSH. SSH provides confidentiality and security for data that is exchanged between the DAS and remote hosts.

Public-key authentication uses an SSH key pair that comprises the following keys:

A private key, which is stored in a secure location on the DAS host and which may be protected with a passphrase
The public key, which is stored on all the remote hosts with which the DAS communicates

The subcommand does not require any configuration information from the DAS and does not modify the configuration of the DAS.

This subcommand is supported in local mode only.

Prerequisites for Using the setup-ssh Subcommand

To use the setup-ssh subcommand, the SSH user must be able to use SSH to log in to remote hosts where SSH is to be set up. Specifically, the following prerequisites must be met:

The ssh(1) client is installed on the DAS host and is accessible through the DAS user’s path.
The sshd(1M) daemon is installed and running on all hosts where an SSH key is to be set up.
The user that the --sshuser option specifies has an SSH login on all hosts where an SSH key is to be set up.
The ssh-keygen(1) utility is installed on the DAS host either at the default location or in a location that is defined in the DAS user’s path.
On Windows systems, the SSH package for Cygwin (http://www.cygwin.com/) or an MKS Software (http://www.mkssoftware.com/) toolkit that provides SSH is installed.

Behavior of the setup-ssh Subcommand

The subcommand sets up SSH connectivity between the DAS host and remote hosts by automating the following tasks:

Generating an SSH key pair. If no SSH key pair exists, the default behavior of the subcommand is to prompt the user to generate an SSH key pair. The SSH key pair is generated without an encryption passphrase. If a passphrase-protected key pair is required, the key pair must be generated manually by using the SSH commandhttp://www.oracle.com/pls/topic/lookup?ctx=E18752&id=REFMAN1ssh-keygen-1[ssh-keygen(1)].
Distributing the public key. The subcommand appends the content of the public key file to the user-home`/.ssh/authorized_keys` file on each remote host. By default, the subcommand locates the public key file in the user-home`/.ssh` directory on the host where the subcommand is run. If the user-home`/.ssh/authorized_keys` file does not exist on a host, the subcommand creates the file. user-home is the user’s home directory on a host.
To distribute the public key, authentication of the user’s SSH login is required. If the private key is protected by a passphrase, the passphrase is also required. By default, the subcommand prompts the user for the password and, if necessary, the passphrase. To distribute the public key without being prompted, run the subcommand as follows:
- Set the --interactive option of the asadmin(1M) utility to false.
- Set the --passwordfile option of the asadmin utility to a file in which the AS_ADMIN_SSHPASSWORD entry specifies the SSH user’s password for logging in to the specified hosts.
- If a passphrase is required, ensure that the file that --passwordfile option of the asadmin utility specifies also contains an entry for AS_ADMIN_SSHKEYPASSPHRASE.
  If public key authentication is already set up on a host, the subcommand informs the user that public key authentication is already set up and does not distribute the key to the host.

Options

asadmin-options

Options for the asadmin utility. For information about these options, see the asadmin(1M) help page.

--help

-?

Displays the help text for the subcommand.

--sshport

The port to use for SSH connections to the host where SSH is being set up. The default is 22.

--sshuser

The SSH user on the remote host that is to run the process for setting up SSH on that host. The default is the user that is running this subcommand. To ensure that the DAS can read this user’s SSH private key file, specify the user that is running the DAS process.

--sshkeyfile

The absolute path to the SSH private key file for user that the --sshuser option specifies. This file is used for authentication to the sshd daemon on the host.
The user that is running this subcommand must be able to reach the path to the key file and read the key file.
The default is a key file in the user’s .ssh directory on the host where the subcommand is run. If multiple key files are found, the subcommand uses the following order of preference:

id_rsa
id_dsa
identity

--sshpublickeyfile

The absolute path to the SSH public key file for user that the --sshuser option specifies. The content of the public key file is appended to the user’s .ssh/authorized_keys file on each host where SSH is being set up. If the .ssh/authorized_keys file does not exist on a host, the subcommand creates the file.
The user that is running this subcommand must be able to reach the path to the key file and read the key file.
The default is a key file in the user’s .ssh directory on the host where the subcommand is run. If multiple key files are found, the subcommand uses the following order of preference:

id_rsa.pub
id_dsa.pub
identity.pub

--generatekey

Specifies whether the subcommand generates the SSH key files without prompting the user.
Possible values are as follows:

true

The subcommand generates the SSH key files without prompting the user.

false

The behavior of the subcommand depends on whether the SSH key files exist:

If the SSH key files exist, the subcommand does not generate the files.
If the SSH key files do not exist, the behavior of the subcommand depends on the value of the --interactive option of the asadmin utility:
- If the --interactive option is true, the subcommand prompts the user to create the files.
- If the --interactive option is false, the subcommand fails.
  This value is the default.

Operands

host-list: A space-separated list of the names of the hosts where an SSH key is to be set up.

Examples

Example 1 Setting Up an SSH Key

This example sets up an SSH key for the user gfuser on the hosts sj03 and sj04. The key file is not generated but is copied from the user’s .ssh directory on the host where the subcommand is running.

asadmin> setup-ssh sj03 sj04
Enter SSH password for gfuser@sj03>
Copied keyfile /home/gfuser/.ssh/id_rsa.pub to gfuser@sj03
Successfully connected to gfuser@sj03 using keyfile /home/gfuser/.ssh/id_rsa
Copied keyfile /home/gfuser/.ssh/id_rsa.pub to gfuser@sj04
Successfully connected to gfuser@sj04 using keyfile /home/gfuser/.ssh/id_rsa
Command setup-ssh executed successfully.

Example 2 Generating and Setting Up an SSH Key

This example generates and sets up an SSH key for the user gfuser on the hosts sua01 and sua02.

asadmin> setup-ssh --generatekey=true sua01 sua02
Enter SSH password for gfuser@sua01>
Created directory /home/gfuser/.ssh
/usr/bin/ssh-keygen successfully generated the identification /home/gfuser/.ssh/id_rsa
Copied keyfile /home/gfuser/.ssh/id_rsa.pub to gfuser@sua01
Successfully connected to gfuser@sua01 using keyfile /home/gfuser/.ssh/id_rsa
Copied keyfile /home/gfuser/.ssh/id_rsa.pub to gfuser@sua02
Successfully connected to gfuser@sua02 using keyfile /home/gfuser/.ssh/id_rsa
Command setup-ssh executed successfully.

Exit Status

0: command executed successfully
1: error in executing the command