Tips and Tricks
Table of contents
‘vi’ and 'vim' text editors
Notes:
- When typing text, press <ESC> once finished. In case you’re blocked, press also <ESC> before executing commands described below
- both editors use case sensitive commands
| Request | Command |
|---|---|
To quit without saving | Press ‘:’ then enter ‘q!’ |
To quit with saving | Press ‘:’ then enter ‘x’ or ‘wq’ |
Go to top of file | Press ‘:’ then enter ‘0’ |
Go to last line | Press ‘G’ |
Search pattern | Press ‘/’ then enter your search text. Press then ‘n’ for next (forward) or ‘N’ for backward |
Remove current character | Press ‘x’ |
Insert text | Press ‘i’ (press ESC once text completed) |
Insert line | Press ‘o’ for a line below cursor, ‘O’ for a line above cursor (press ESC once text completed) |
Delete a line | Press ‘dd’ |
'vim' has also a graphical version named 'gvim'. If not installed, you can run: # yum -y install gvim
‘gedit’ graphical editor
‘gedit’ is a graphical text editor, users familiar with Windows notepad should not encounter difficulties to use it.
| Request | Command |
|---|---|
To quit | close the window by clicking on the cross top right corner |
Save file | Press <CTRL-S> |
‘nano’ text editor
‘nano’ is a basic text editor, very simple to use and displaying available commands at the bottom of the screen. For example, to leave ‘nano’ , use ^X (press CTRL + X)
How to setup ‘ssh’ trusts between Linux and HP-UX
Notes
- The prompts will tell you where to execute the commands, "
HPUX#" (root user) or "Linux#" (root user) - Remember Linux/Unix is case sensitive
- If hosts are not known by each other, fill the
/etc/hostsfile for example (usingvifor example) - linuxhost represents the name of your Charon server (can be any name you want)
- hpuxhost represents the hostname of your HP-UX virtual machine
On the HP-UX system, enter the following commands if the folder does not already exist:
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On the Linux server, enter:
→ Do not specify any passphrase.
→ Enter the password for the copy operation to complete |
On the HP-UX system, add the Linux server key to the authorized keys:
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Perform a simple test on the Linux server:
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If trying to execute a remote command on the HP-UX system, a message telling "no matching cipher found" is displayed, the cipher has to be setup on the Linux server side in the /root/.ssh/config file:
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How to install 'rsh' on RHEL 8
To setup 'rsh' on RHEL8, use the following commands:
# dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm# ARCH=$( /bin/arch )# subscription-manager repos --enable "codeready-builder-for-rhel-8-${ARCH}-rpms"# dnf -y install rsh |
More information in this article: rsh and rsh-server packages missing in RHEL 8
How to setup ‘rsh’ trusts between Linux and HP-UX
Notes
- The prompts will tell you where to execute the commands, "
HPUX#" (root user) or "Linux#" (root user) - Remember Linux/Unix is case sensitive
- If hosts are not known by each other, fill the
/etc/hostsfile for example (usingvifor example) - linuxhost represents the name of your Charon server (can be any name you want)
- hpuxhost represents the hostname of your HP-UX virtual machine
Introduction
RSH executes commands on a remote host. It can be used to issue a shutdown on the Charon Tru64 virtual machine.
Pre-requisites
The RSH method requires the 'rsh' package. It can be installed using the following command:
Linux# yum install rsh |
Notes
On the HP-UX system issuing the shutdown, create a proxy between the root user of the Charon server and the user.
Example:
HPUX# echo "linuxhost root" >>~/.rhosts |
If the Charon server name is not known to the TCPIP database, edit the /etc/hosts file and add the server ip address and its name.
Ensure manual commands can be passed to the HP-UX system from the Charon server.
Example:
Linux# rsh linuxhost date |
If a "poll: protocol failure in circuit setup" is returned, the firewall settings have to be set to open ports 1011 to 1023.
Please always refer to your network administrator when changing the firewall rules, commands below are given as example only.
Example:
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Shutdown guests with Expect tool
Introduction
In case SSH nor RSH can not be used to perform clean shutdown of the guests, the "expect" tool can be used to connect to the console, perform the login operation and execute the shutdown command depending on the console status.
The operations performed during the "expect" script execution are detailed in the VM management - Create/Edit guest stop script chapter.
In this case the password is sent without encryption.
To facilitate use of "expect" for shutdown, an example is provided in the "guest_shutdown.exp" script located in the /opt/charon/utils folder. If you plan to customize the script, you'll have to create a copy and not use it directly as it will be overwritten in case of Toolkit upgrade.
'telnet' and 'expect' packages must be installed in order to use this feature.
The following error message can be returned when stopping the virtual machine when trying to use the expect script example:
- if expect package is not installed: "
Stop script returned error code 126". - if telnet is not installed: "
%EXPECT-F-NOSRM, Cannot continue, 'telnet' is not installed" then "Stop script returned error code 4"
Caution: the virtual machine process will be however killed by service management process
Console locked:
Any active session to the console must be killed before the "expect" script is executed.
For example, if you are connected via "telnet" on the localhost/port (the kill is not done inside the expect script). Using the "/opt/charon/utils/charon_gstart_expect" script file the necessary operations will be performed.
If the console is locked from another host (if you use putty for example), you will have to cancel the connection by yourself otherwise the shutdown will not be performed cleanly.
Script usage
Usage:
# path/script <port> <user> <password> <prompt> <opsys>
Parameters:
| Parameter | Description |
|---|---|
| <port> | telnet port number (example: 30001) |
| <user> | username for login (must be able to perform shutdown) |
| <password> | password |
| <prompt> | shell prompt (including end space) or last characters of the prompt |
| <opsys> | HPUX or MPEIX (case sensitive) |
Example for HP-UX:
# /opt/charon/utils/guest_shutdown.exp 30001 root 12345 "# " HPUX |
Example for MPEIX:
# /opt/charon/utils/guest_shutdown.exp 30001 X X X MPEIX |
How to restart CHARON-PAR on Linux automatically on failure
Automatic restart on failure is managed by systemd at Linux level, please refer to systemd man pages.
For example, edit the service configuration file and add the following parameters:
| Parameter | Type | Description |
|---|---|---|
Restart | text | Configures whether the service shall be restarted when the service process exits, is killed, or a timeout is reached |
RestartSec | numeric | Configures the time to sleep before restarting a service (as configured with Restart=). Takes a unit-less value in seconds, or a time span value such as "5min 20s". Defaults to 100ms. |
StartLimitInterval | numeric | Configure service start rate limiting. By default, services which are started more than 5 times within 10 seconds are not permitted to start any more times until the 10 second interval ends. With these two options, this rate limiting may be modified. Use StartLimitInterval= to configure the checking interval (defaults to DefaultStartLimitInterval= in manager configuration file, set to 0 to disable any kind of rate limiting). Use StartLimitBurst= to configure how many starts per interval are allowed (defaults to DefaultStartLimitBurst= in manager configuration file). |
StartLimitBurst | numeric |
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