<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<font size="-1">To add some Linux traffic to the list...<br>
<br>
Centos 7 has recently come out, and I am fiddling my way through
it. There are a number of things that surprised me. <br>
<br>
MariaDB replaces mysql. MariaDB is a fork of mysql with some of
the original developers. Oracle is doing some things in a
not-so-friendly to open-source way with mysql, so a number of
distros are making this leap. MariaDB is supposed to be entirely
compatible with mysql, but will have some additional options that
mysql does not have.<br>
<br>
systemd has replaced init / upstart scripts. So all the startup
scripts are quite different than they were before; living in
different directories and not using bash scripts to handle
things. systemd also does logging, so some distros will no longer
have their main logging go to /var/log and be textfiles. For
people who have made their own daemons in the past, there are some
things systemd assumes which may require you to make changes to
your programs.<br>
<br>
Centos used to use Lokkit, and are switching to firewalld. That
is a fairly substantial change. It is still iptables based, but
it has some odd ramifications for how things are done. Firewalld
lets you make changes to your firewall that are persistent or
temporary. Usually configuration is done by making changes to
config files instead of having them done programatically.<br>
<br>
NetworkManager got put in the mainstream of Centos6, but is even
more-so in Centos 7. NetworkManager is supposed to do a better
job in dealing with mobility; when you change location, it adjusts
the IP configuration to match. This is great for laptops, but is
a little awkward for servers. Anyway, most of the network configuration
is now done with the "nmcli" command.<br>
<br>
Which leads me to the depressing news that Centos has finally done
away with ifconfig, arp, netstat, mii-diag, route and a number of
the other "standard" network tools. You can still install the
net-tools package, but those commands have mainly been replaced by
"ip." This is a bit of a break because most of those other tools
come default on Windows computers (though with slightly different
names) I always looked really awesome when, as a Linux techie, I
could sit at a command-prompt of a Windows machine and determine
what was going on with their network faster than they could from
the GUI. Now I will need to resurrect my non-linux command-set to
look so smart. Drat.<br>
<br>
Centos also uses xfs by default. I have not run into anything
with that, but I know there are a number of things I used to take
for granted with the ext[2,3,4] filesystem that I will need to
revisit.<br>
<br>
They have also jumped kernels to the 3.x series instead of the
2.4/2.6 kernels. I have not yet begun to look into what the difference
in the kernel is.<br>
<br>
I have really enjoyed how chrony keeps my VMs time to be correct.
I have no idea how well that will scale. ntp creates a lot of
network traffic, and suddenly having a lot of boxes checking ntp
on a much more regular basis may cause a lot of the ntp servers to
go away. But it is a very nice service to have running on my
Virtual Machine!<br>
<br>
Anyway. It will be interesting to see how Centos 7 pans out. For
myself, I will need to update all sorts of training materials that
we have built to incorporate all this new stuff.<br>
<br>
- Tim Young<br>
<br>
</font>
</body>
</html>