Cpanel DNSONLY tailwatchd failed

July 12th, 2011

My Cpanel DNSONLY (secondary DNS) server started to send errors by email few days ago.

tailwatchd failed @ Tue Jul 12 09:35:01 2011. A restart was attempted automagically.

It turns out that I needed to install MySQL for tailwatchd to work properly again (whatever that daemon does).

What I need to do :

  1. Remove /etc/mysqldisable
  2. /scripts/mysqlup –force
  3. /scripts/checkperlmodules
  4. /etc/init.d/cpanel restart
After that, you may check /usr/local/cpanel/logs/tailwatchd_log to be sure that there is no error message.

Setting up NTP on RHEL/Centos

October 4th, 2009

I may have missed something obvious, but it seems that the default ntp.conf shipped with RHEL 5 is not working…

I just want to configure my servers to sync time with a public NTP server. Using the default configuration (/etc/ntp.conf), ntpd starts correctly but never writes anything to /var/log/messages besides the first lines at startup.

What I have found is that the “restrict” lines in the default ntp.conf file do not seem to allow ntpd to connect to the servers that are listed there (*.centos.pool.ntp.org by default). Adding the following lines fix the problem :

restrict 0.centos.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery
restrict 1.centos.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery
restrict 2.centos.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery
# the following is in the default ntp.conf file
server 0.centos.pool.ntp.org
server 1.centos.pool.ntp.org
server 2.centos.pool.ntp.org

Also (as an alternate fix) I had success with the following servers :

server ntp.isc.org
server clock.redhat.com

I’m not sure why, I suspect that’s because in the DNS they resolve to a single IP address, but I don’t really understand what would cause this.

Anyway, with these changes my NTP now sync properly, and I can see the “synchronized to 206.248.171.198, stratum 1″ lines in the /var/log/messages file.

server ntp.isc.org
server clock.redhat.com

Plone 3 : Changing the title for custom Zope 3 views

September 14th, 2008

Recently I needed to change the title for a custom Zope 3 view. The title is displayed in the “Display” menu, when you add the view as one of the “Available view methods” of the content type. The text shown by default is the view name (usually something like viewname_view), which is not very user-friendly. Read the rest of this entry »

Copying a partition table to another disk

September 5th, 2008

This week I added a new hard drive to a server, meant as a spare drive for the RAID 1 array (linux software RAID). To activate the partitions as spares, I needed to recreate exactly the same partitions as the other disks (same size).

I first tried doing that manually with GNU parted, but that turned out to be hard to do, it seems I could never get the partitions to have exactly the same size…

So I searched a bit on Google, and found a way to make a backup of the partition table of one disk, and copy it to another disk very easily. As usual, the dd command is always a great tool for that kind of job. Read the rest of this entry »

How to make a safe kernel upgrade by SSH

February 15th, 2008

There’s been a local root exploit discovered in the Linux kernel recently, which obliged me to manually compile new kernels on some of my servers. The problem with that : I rarely compile new kernels for these servers, so I’m not sure it will boot at all. Moreover, the servers are located in a datacenter I can’t access easily, so manually choosing the kernel in the grub boot menu is not an option. Fortunately, grub provides a feature to help with that. Read the rest of this entry »