Troubleshooting and Error Messages Tips for Platform and OpenLava

Troubleshooting and Error Messages Tips for Platform. But it can be used for OpenLava. Do take a look and digest.

Troubleshooting and Error Messages

udev: renamed network interface eth0 to eth2

I was encountering this error when I start the network

# dmesg |grep eth0 
udev: renamed network interface eth0 to eth2

This occurs when you clone or change the NIC hardware and the OS still retain the old interface information in /etc/udev/rules.d/70-persistent-net.rules.

Just delete /etc/udev/rules.d/70-persisitent-net.rules and reboot the system so the Linux can rebuild the /etc/udev/rules.d/70-persistent-net.rules that match the replaced NIC hardware.

# rm  /etc/udev/rules.d/70-persistent-net.rules
# reboot

Failed to conect to FastX Server

Do take a look at Failed to start a secure connection to the server

Basically, to fix this issue, run the command from your linux machine:

# killall fastx_server 

Relaunch the FastX Client

No irq handler for vector on CentOS 6

If you are getting error messages on the /var/log/messages on your CentOS 6. You may want to see Redhat Bugzilla "No irq handler for vector" error, sluggish system"

Aug 20 11:22:58 node1 kernel: do_IRQ: 2.135 No irq handler for vector (irq -1)

Step 1: Edit Grub Bootloader. Add the pci=nomsi,noaer to the end of the kernel options

# vim /boot/grub.menu.1st

default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS 6 (2.6.32-504.el6.x86_64)
        root (hd0,0)
        kernel /vmlinuz-2.6.32-504.el6.x86_64 ro root=/dev/mapper/vg_cherry-lv_root rd_NO_LUKS  KEYBOARDTYPE=pc KEYTABLE=us LANG=en_US.UTF-8 rd_NO_MD rd_LVM_LV=vg_cherry/lv_root SYSFONT=latarcyrheb-sun16 crashkernel=128M rd_LVM_LV=vg_cherry/lv_swap rd_NO_DM rhgb quiet pci=nomsi,noaer
        initrd /initramfs-2.6.32-504.el6.x86_64.img

Step 2: Disable irqbalance daemon

# service irqbalance stop
# chkconfig --levels 2345 irqbalance off

Step 3: Reboot the System

# reboot 

References:

1.  Red Hat Bugzilla – Bug 225399
2.  No irq handler for vector

Using Python 2 on JupyterHub

If you are installing and configuring JupyterHub, do take a look

1. Basic Setup and Configuration of JupyterHub with Python-3.4.3 

By default, JupyterHub uses Python 3.3. However you may want to use Python-2 on JuypterHub. You may want to take a look at Basic Setup and Configuration of JupyterHub with Python-3.4.3

Step 1: Install latest version of Python-2
You may want to see Installing and Compiling Python 2.7.8 on CentOS 5. You can apply this for CentOS 6

Step 2: Remember to install iPython2 and iPython[notebook] on Python-2
Do take a look at Installing scipy and other scientific packages using pip3 for Python 3.4.1 for some similar ideas

 Step 3: Install Python KernelSpec for Python 2

# /usr/local/python-2.7.10/bin/python2 -m IPython kernelspec install-self
# /usr/local/python-3.4.3/bin/python3 -m IPython kernelspec install-self

Step 4: Restart JupytHub

# juypterHub