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22 troubleshooting ssh delays – HP Insight Control Software for Linux User Manual

Page 252

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Corrective actions

Cause/Symptom

Set the SSH credentials for the target system using the HP
SIM Options

Credentials tool. Specify Global or

System

credentials as appropriate. For more information,

see

“Setting SSH credentials on managed systems”

(page 197)

and the HP Systems Insight Manager online

help.

Unable To Get SSH Credentials: SSH Credentials For
the Specified Server Were Not Set Or Are Missing

The credentials for the SSH protocol settings are missing.

Set the SSH credentials for the target system using the HP
SIM Options

Credentials tool. Specify Global or

System

credentials as appropriate. For more information,

see

“Setting SSH credentials on managed systems”

(page 197)

and the HP Systems Insight Manager online

help.

SSH Authentication Failed

The user name, password, or both for the SSH credentials
of a target system are incorrect, causing SSH to fail.

23.22 Troubleshooting SSH Delays

Cause/Symptom:

SSH delays on SLES managed systems on networks without name resolution

You might encounter extended delays when trying to use SSH to access a SLES managed system
on a network that does not have DNS name resolution configured or does not have a well
populated /etc/hosts file.

Such a configuration might exist if your managed nodes are on an internal private network,
which is typical for many high performance computing applications.

Corrective action:

The following actions fix this issue:

Configure a DNS resolver on the network in question.

On the managed system, modify the /etc/hosts file to include both the CMS and the
managed system. The entry for each must contain a fully qualified name and a short alias.
It is not necessary that the name is a real registered domain name because the network has
no name resolution.

For example, if the CMS is at IP address 192.0.2.1 and the managed node is at IP address
192.0.2.10, add two lines that look like this:

192.0.2.1 saturn.example.com saturn
192.0.2.10 terra.example.com terra

Edit the /etc/ssh/sshd_config file to modify the configuration of the sshd server to
turn off name resolution, as follows:

UseDNS no

Turning off name resolution on the sshd server fixes only the SSH connection delay; it does
not fix the hostname -s delay.

Automatic fix for Insight Control for Linux installations

To eliminate this delay whenever you

use HP Insight Control for Linux to install a Linux OS on a server, do the following:

1.

Create a master /etc/hosts file for your private network that contains all servers on your
internal network as described previously in this section.

2.

Store the master /etc/hosts file in the Insight Control for Linux repository and use /opt/
repository/hosts.txt

as the file name.

3.

Modify the AutoYaST file you will be using for the installation by adding a line similar to
the following after the line with the %%agentinstall%% statement:

wget 192.0.2.1:60000/hosts.txt -O /etc/hosts

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Troubleshooting