title: Migrating from CentOS to Ubuntu link: https://onemoretech.wordpress.com/2008/12/13/migrating-from-centos-to-ubuntu/ author: lembobro description: post_id: 419 created: 2008/12/13 04:10:02 created_gmt: 2008/12/13 04:10:02 comment_status: open post_name: migrating-from-centos-to-ubuntu status: publish post_type: post

Migrating from CentOS to Ubuntu

It’s been a long time coming, but the day has finally arrived. Tonight I begin migrating my home environment from CentOS over to Ubuntu. The first target will be my own workstation, that also serves up DNS and hosts a half-dozen VMware Server virtual machines used in testing operating systems and application software. Right now I’m doing some research to decide whether to go with the latest version, 8.10, or it’s Long Term Support counterpart, 8.04 LTS. I’ve also got to decide whether to use the x86_64 or i386 platform version. While my Dell 5150e motherboard doesn’t really support full 64-bit operations (at least no memory mapping, even with 64-bit CentOS I only see 3 or 4 Gb RAM), running x86_64 on at least one machine has given me valuable experience.

A few resources I’ve come across so far.

Switching to Ubuntu from RedHat. This is a terrific howto that provides a concise but thorough orientation to Ubuntu for experienced Red Hat admins. It is mostly in tabular format, providing the Ubuntu equivalents for critical Red Hat commands. One thing it gets wrong (or incomplete) is the equivalent to the oft-used rpm -qa | grep [package name]. The article says to use dpkg --list, but this will give you a list of all packages, even those not installed on the system. The correct command would be dpkg --get-selections | grep -v deinstall | grep [package name].

SSHHowto, provides guidance in installing and configuring an ssh server on your box (by default, Ubuntu Desktop only provied an ssh client).

Bind9ServerHowto, sets out how to install and set up the latest BIND for providing naming services.

Because I’m setting up a static IP for my machine, I’m going to disable NetworkManager and use the old-fashioned manual way to set up my network interfaces (the primary for my host, another as a virtual for the DNS name server).

sudo apt-get remove --purge network-manager

Once I’ve done this, it will be time to make sure /etc/hosts and resolv.conf are configured correctly. The interface definition itself resides at /etc/network/interfaces. My main source of knowledge about all that is in this article.

P.S. Decided to go with 8.04 LTS on my home workstation after all, mostly for stability. When it comes time to convert the home laptop I’ll consider whether 8.10 offers anything more in terms of hardware support (especially power management, always a dicey affair with Linux).

Also will continue to run x86_64 on my 64-bit crippled hardware (more proof that Dell’s reputation as a visionary company is no longer deserved, if it ever was). There are challenges to the latter, like web browsing with standard 3rd party plugins. We all know that nspluginwrapper really doesn’t work, but just won’t admit it.

Because some stuff is only available in 32-bit, compatibility libraries are needed. The following packages are a must:

`

ia32-libs
lib32asound2
lib32asound2-plugins
util-linux
libc6

`

I’ve installed the latest Firefox 3 tarball in /opt/firefox32 and done a symlink from /usr/lib/mozilla/plugins to /opt/firefox32/plugins. I’ve also linked /opt/firefox32/firefox to /usr/bin/firefox32 and created a custom firefox32.desktop menu item for it. This seems to work pretty well. I did have to go into about:config and change network.dns.disableIPv6 from “false” to “true” in order to use it. There’s a howto called AMD64FirefoxAndPlugins that covers this for Ubuntu versions down to Gutsy (7.10).

P.P.S. Ubuntu installs with full IPv6 support out of the box. Which really sucks, because most of us have routers at home that won’t route IPv6, or at least not in their default config, and have home DNS servers that aren’t configured to do IPv6 name resolution.. To disable IPv6 I wrote a file, /etc/modprobe.d/disable_ipv6, that contained the lines:

alias net-pf-10 off alias net-pf-10 ipv6 off alias-ipv6 off blacklist ipv6

and rebooted.

Look for other IPv6 stuff under /etc, like one of the configs under /etc/bind9, and be sure to comment them out. Did I mention that IPv6 support sucks? (Right now my little brother the PhD. is laughing because he gets Internet2 access through the university he works for).

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