Setting Up Red Hat Virtualization with Single Server

Red Hat Virtualization is an interesting and powerful platform software, but it is rather challenging to setup with only a single host when compared to Hyper-V, VMware and VirtualBox. One may argue that RHEV is not design for single host (I guess that is why there is no single article about how to do the setup), but who really care if just want to use for a tiny scale deployment? Single host rules!

Well, I could go for RHEL + KVM, but I simply like the interface of RHEV.

Getting it up and running requires user to have experience from numerous area of expertise. This simplified guide is not for newbie.

Setting up the RHVH is not hard. I'm going to skip it. Now, in order to get the hosted-engine up and running, please make sure the following are done:

1. Change the hostname localhost.localdomain to hostname. In my case, I use robustpoc.
2. Be sure to set a fix IP in /etc/sysconfig/network-scripts/ifcfg-eth0 and reconnect using the new IP using ifdown eth0 and ifup eth0.
3. Edit /etc/hosts to resolve the host IP address to the hostname.
4. In order to make this IP change persistent, be sure to change the settings in /var/lib/vdsm/persistence/netconf/nets/ovirtmgmt

Note: If the server is in a VLAN Network, be sure to set a correct gateway otherwise it would not be able to connect to Internet or reach by others in the network.

5. Now, before proceed with executing hosted-engine --deploy, you require to add your FQDN to /etc/hosts. In my case, I use 192.168.0.26 robustpoc.com. This is critical.
6. Next, setup NFS share. Follow the guide below:

Setup NFS server: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/storage_administration_guide/nfs-serverconfig

Configuring NFS server: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/storage_administration_guide/nfs-serverconfig

7. At this point, we are ready to execute hosted-engine --deploy.

Three critical settings to take note during the process:
8. Be sure NOT to set the memory of the VM to maximum available memory of the system as per suggested by the setup. Setting to maximum will lead to no available memory to create any single Virtual Machine.
9. Be sure to use a fixed IP for the engine. Make sure gateway is correct too.
10. Be sure to answer YES when asked whether to update the /etc/hosts for both the host and engine VM. The default answer is NO. Missing out this would be a killer later.

Until this point, everything critical should have already been taken care of. Cross finger and I wish you the best luck!

Common errors that I have encountered but do not guarantee to happen:
1. Error: [Get Local VM IP] failed
2. Info: [Waiting for local VM to be up]
3. [ ERROR ] Failed to execute stage 'Closing up': Failed executing ansible-playbook; then I can access to RHEV Manager but an failed external hosted engine present in the Compute > Hosts.

Welcome to share with me your installation experience, I'm happy to listen and learn from you.

[Ubuntu] Oracle Java 7 Runtime Installation Error

First, I didn't not use manual method for the installation. Instead, I used the PPA method which discussed under here:
http://www.ubuntugeek.com/how-to-install-oracle-java-7-in-ubuntu-12-04.html

However, the installation halted in half way due to my HDD running out of space.

After cleaning up the space and re-run with:

apt-get install -f

It keeps giving me this error:

 Setting up oracle-java7-installer (7u15-0~webupd8~1) ...  
 Installing from local file /var/cache/oracle-jdk7-installer/jdk-7u15-linux-x64.tar.gz  
 Removing outdated cached downloads...  t
 mv: cannot move `jdk1.7.0_15' to `java-7-oracle/jdk1.7.0_15': Directory not empty  
 dpkg: error processing oracle-java7-installer (--configure):  
  subprocess installed post-installation script returned error exit status 1  
 Errors were encountered while processing:  
  oracle-java7-installer  

And this error has disabled Synaptic Package Manager from function properly.

Tried a few solutions but to no avail:

• apt-get purge

  - cannot be run

• apt-get autoremove

  - cannot be run

• dpkg --remove --force-remove-reinstreq oracle-java7-installer

• http://www.khattam.info/solved-subprocess-pre-removal-script-returned-error-exit-status-2-error-2009-08-04.html - This is a great article suggesting a few solutions, big thanks to the author. It may help you to solve Java7 installation problem, give it a try. Especially the step 6, it has successfully remove the oracle-java7-installer and get apt-get work again, but that does not install Java 7 which is our initial intention. Read on...
• Remove the installer file located in /var/cache/oracle-jdk7-installer, then re-download & run the installer... cannot resolve the problem as well

And what did the magic is... delete the directory 'jdk1.7.0 15' located inside the 'java-7-oracle', then re-run the installer apt-get install -f. Voila! The installation should complete without any more hassle.

What happened?

The 'jdk1.7.0 15' & 'java-7-oracle/jdk1.7.0 15' are actually located in /var/cache, but for some reason the 'jdk1.7.0 15' is already exist in 'java-7-oracle' folder. When the installer try to copy it into the parent folder, it cannot overwrite it, suggested by the error message 'Directory not empty'.

Somehow, this cannot be solved by changing the directory write permission, so delete the directory has become the immediate working method.

[Ubuntu] DraftSight installation

DraftSight installation is not as simple as it seems to be even though it comes with .deb file. The dependencies are not fully resolved, leaving out a few modules required by DraftSight missing. The error message that appeared is:

Failed to load modules

If this happened, simply install the following:

1. Install this first alone:

   sudo apt-get install ia32-libs

2. Then install:

   sudo apt-get install libdirectfb-extra libxcb-render-util0

If the above do not solve DraftSight start up issue, then try the method discussed in this helpful article:

http://linuxaideddesign.blogspot.com/2012/03/draftsight-and-ubuntu-1204-lts-64bit.html

How to Fix Multi-boot - Lost of any OS installed before Ubuntu

Big thanks to Ryugamine Mikado from General Linux Discussion Malaysia for sharing such a nice option to fix the multi-boot!

@Tecsun Yeep hi there oh it actually scans the entire disk for all OS and it has been PROVEN to recover any type of OS (i myself used it once to recover my arch when I accidentally fuk'd up my grub.conf) plus many more options such as recovering partition tables , bootsectors and such but i think it only works with GRUB/GRUB2 ,so if you're using another type of bootloader such as LILO you would have to resort to something else

The GUI method of fixing the multi-boot - lost of any OS installed before Ubuntu is well documented here: https://help.ubuntu.com/community/Boot-Repair

Here's a screenshot of it:

How to Fix Multi-boot, Fedora Gone after Install Ubuntu

Updated 30 Jan 2013 11.25pm:
A much more user-friendly method with GUI. Click here to see how.

---

I was installing multi boot environment on my laptop, it will be consist of:

1. Windows 7 Pro
2. Fedora 18
3. Ubuntu 12.10

Fedora & Ubuntu both use Grub2 to multi boot, installing Fedora after Windows work fine, but once Ubuntu was installed only Windows 7 can be seen from the list, Fedora was gone. How do we fix that inside Ubuntu?

There are various fix on internet which can be concluded below:

1. update-grub: you might have to install grub first before you able to run this command
2. grub-customizer: this is very handy GUI to manipulate the Grub. It supports Grub2 and it is real intuitive to add new OS onto the Grub menu list.
3. manual configuration by typing entries: intermediate/advanced user might appreciate this but definitely not for novice user. There are too many things to learn before one can eventually get it run correctly.

The first two methods are the most straightforward method, but it might not work as expected sometimes. My version of getting this solve is pretty simple, despite it required to work with method no. 3.

* To edit grub.conf user is required to open Nautilus with sudo privilege. Make sure you have run sudo nautilus & in terminal to be able to open and edit the configuration file in text editor.

1. First thing you have to know where the Grub configuration file is stored. It is located under /boot/grub/grub.conf. Open it with a text editor.
2. Then you have to know where is your Fedora /boot located. We don't need terminal as we love GUI. Go to Dash Home > Disks.
3. If you follow Fedora installation guide you can easily identify the /boot, which is 25x MB in size. There are two in my Disks Manager, but the already mounted one is for Ubuntu. So the other one is Fedora for sure.
   
   
4. Mount the Fedora /boot by select the partition and press the play button. 
5. Open the /boot/grub2/grub.conf with text editor.
6.  Locate the following and COPY the whole content except for the ###BEGIN....### & ### END....###:

7.  ### BEGIN /etc/grub.d/10_linux ###  
    menuentry 'Fedora' --class fedora --class gnu-linux --class gnu --class os
   . 
   .
   . *this dots mean there are a lot of content in the middle but being skipped
   . for ease of reading purpose
         }  
    }  
    ### END /etc/grub.d/10_linux ###  

8. After that, switch to your Ubuntu's grub.conf, and paste into ### BEGIN /etc/grub.d/40_custom ###, see screenshot below:
   
   
9. Save the Ubuntu's grub.conf and reboot.

Voila! My Fedora 18 is now shown on the Grub boot menu.

[Ubuntu] How to disable guest & remote login account in 12.10?

Having the Guest and Remote Login account enabled by default is really not my preference. Personally I think these two accounts should be disabled by default especially privacy is getting more & more important to individual nowadays where most of private files are stored digitally.

I'm not sure why Ubuntu chose to enable them, but if you just hate it like I do, you can disabled them by:

Remove guest account:

sudo /usr/lib/lightdm/lightdm-set-defaults -l false

sudo /usr/lib/lightdm/lightdm-set-defaults --allow-guest false

Remove remote login:

sudo /usr/lib/lightdm/lightdm-set-defaults -R false

sudo /usr/lib/lightdm/lightdm-set-defaults--show-remote-login false

Remove both:

sudo /usr/lib/lightdm/lightdm-set-defaults -l false -R false

sudo /usr/lib/lightdm/lightdm-set-defaults --allow-guest false --show-remote-login false

Do remember to reboot after that.

I have once cannot configure it probably with the full command "--allow-guest" and "--show-remote-login" even without typo error. If you do encounter that, simply use the "-l" and "-R".

[CentOS] Install OpenERP 6.1 on CentOS 6.3

This article is about how to install OpenERP on my newly installed CentOS 6.3:

Here's an article I found online which provide steps by steps guide:
http://intellectseed.wordpress.com/2012/11/06/how-to-install-openerp-on-centos/

[CentOS, Fedora] Yum for novice user

There are a lot to learn about Yum, for novice user below are a few very useful method to get you started with installation using Yum:

• # yum install XXXXX

This command is to install a known program. Normally a program would end with "x86_64" for 64-bit CentOS / Fedora.

• # yum search XXXXX

This is very useful when you know the name of the software, but do not know how the repo name it. Wildcard is not supported here, because no matter what you type, it will treat is a "contain", mean if I search for "fire", I could eventually get "Firefox".

• # yum list XXXXX

List is similar to search, but wildcard is not enabled by default. So if you wanna search for "Firefox", you have to type "fire*".

• # yum groupinstall XXXXX

Group install is very useful not only to resolve dependencies, but it also helps by installing other features that require by particular software. For example, Libre Office, by default installation, it would sometimes not appear in the Application Menu. By doing groupinstall all LibreOffice program will be added to the application menu automatically.

* I have not really dig into the groupinstall behaviour, so might explain wrongly here. To be precise, here's how yum.baseurl.org explained:

Despite their differing names both of these commands perform the same function. They will attempt to install/update all of the packages in the group that are of the types 'default' or 'mandatory' (by default). (To change this types of packages edit the value of the group_package_types option in yum.conf.) And they will install any additional dependencies needed by any of the installing/updating packages.

• # yum update

As the name suggest, this is use to update the system to the latest available patches. Worth to mention here, for those who use Ubuntu / Fedora / CentOS together might get confused a bit, as Ubuntu apt-get update is only to update the repository, but not to perform update to the system. Use apt-get upgrade instead.

I hope this will help many who just start playing around with Yum. Have fun!

[Fedora] How to disable C6 Media Repo

There are two methods being discussed online:

• yum --disablerepo=c6-media
• yum-config-manager --disable c6-media (this one work for me)