Everyone who has had experience with SLES 12 and RHEL 7.1 and later versions has seen that the bootloader used on Linux on POWER is now GRUB2. This was a change as compared to the mix of Yaboot and LILO used by the previous versions, namely up to SLES 11 SP4 and RHEL 7.0.
This change affects the way input parameters to the bootloader are given; for instance the location of the kernel or the initrd or initramfs, or several other inputs, that usually do not require intervention of the non-advanced user, except when launching a brand-new installation.
Users of Linux on POWER interacted with the bootloader during installation, in which they were presented with two choices: a text-based install, or a graphical install. While the former was easier to start as the default option, it was quite cumbersome to navigate and not as user-friendly as the latter.
The graphical install makes use of a VNC server and enables the access to a user-friendly GUI via IP, by which users can more easily customize the options they like for their installation. In PowerKVM, no user intervention is required if using Kimchi, because the VNC will output to the noVNC in-browser implementation; in other words, the VNC GUI will show up automatically in the browser.
In PowerVM, on the other hand, this requires the input of specific parameters on the command line, and a VNC client like TigerVNC on the the user's workstation in order to access the VNC server on the target system. While for Yaboot/LILO bootloaders this has been quite well documented, for newer versions it is not. This article describes which these parameters are.
Starting a VNC from up to SLES 11 SP4 / up to RHEL 7.0 (Yaboot/LILO bootloader):
The input parameters for starting a VNC Server install on the older Yaboot/LILO bootloaders are:
- For SLES up SLES11 SP4 : install vnc=1 vncpassword=passw0rd
- for RHEL up to RHEL 7.0: linux vnc vncpassword=passw0rd
Here is an example for SLES 11:
You will then be asked the IP parameters (address, gateway, netmask and DNS) that you want to assign to the target machine, so that you can later connect via VNC. The word "passw0rd" can be any of your choice, and it's the password you will use when connecting from your workstation to the target system's VNC Server.
Starting a VNC from SLES 12 / RHEL 7.1 and above (GRUB2):
To input parameters for starting a VNC Server install on newer GRUB2 bootloaders is a little bit more cumbersome. When starting the LPAR with the attached ISO of the Linux distribution for the first time, the user is presented first with the following menu (in this case, I am using the HMC's terminal connection on a SLES 12 machine):
This menu consists of several lines that actually implement a command, thta can be seen by highlighting the line entry and pressing "e" on the keyboard. We want to know what "Installation" implements, so we click on that, and we see the following:
In order to start a VNC install, unfortunately the SLES and RHEL documentation is not very accurate in this regard so far. So in our lab we have found that the input to be provided is the following:
- Append the following string, according to your distribution, at the end of the line starting with "linux":
- For SLES 12 and above: ifcfg=eth*=192.168.1.10/24,192.168.1.1 vnc=1 vncpassword=passw0rd
- In case you also wanted to add other information already, like name server and hostname details, here is the string to use:
ifcfg=eth0=<IP Address>/<Netmask range>,<Gateway>,<nameserver> hostname=<host name> vnc=1 vncpassword=passw0rd
- For RHEL 7.1 and above: ip=192.168.1.10 netmask=255.255.255.0 gateway=192.168.1.1 vnc vncpassword=passw0rd
Where obviously the IPs I have provided are an example, and you should use your parameters.
Here is an example of what it will look like in SLES 12 after you have provided the above parameters (of course the "\" is there because there was not enough space left on the line in the console, the user should not write it).
After that, click on CTRL+x and move on, after some time you should get a message saying that you can now connect to the VNC server with a VNC client on your workstation. TigerVNC is one of the options. Start the program, enter the address of the target server with a ":1" at the end (in this case for example 192.168.1.10:1), then enter the password (in this case passw0rd), and you can move on with the GUI installation!
One VNC client: TigerVNC
General Info: http://tigervnc.org/
Installing Linux on POWER: IBM official documentation
SLE official guide for VNC installation in SLES 12 (attention: in SLES 12 this solution won't work! use the one cited here in this article; at the time of writing, the documentation has not been updated by Novell, but we told them the solution
RHEL 6.x installation with VNC