As I didn’t get chance to have a play with the pre-release CentOS 7.0 builds I decided to wait until DigitalOceanexternal link lauched their imageexternal link which they did just in time for the weekend.

Check the IP Address

First thing I did was type in ifconfig and got …..

[root@server ~]# ifconfig
-bash: ifconfig: command not found

….. not a good start, have dabbled with a Fedoraexternal link when I installed OpenShiftexternal link I remembered about the ip command …..

[root@server ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
 inet 127.0.0.1/8 scope host lo
 valid_lft forever preferred_lft forever
 inet6 ::1/128 scope host 
 valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
 link/ether ff:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
 inet 123.123.123.123/24 brd 123.123.123.255 scope global eth0
 valid_lft forever preferred_lft forever
 inet6 fe80::fe80:fe80:fe80:fe80/64 scope link 
 valid_lft forever preferred_lft forever

….. I can see a lot of muscle memory having to be re-learned.

Restarting services

Next up is a change I was expecting, the introduction of systemdexternal link  …..

[root@server ~]# yum install httpd
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.awanti.com
 * extras: mirror.awanti.com
 * updates: mirror.awanti.com
Resolving Dependencies
 → Running transaction check
 — -> Package httpd.x86_64 0:2.4.6–17.el7.centos.1 will be installed
 → Finished Dependency Resolution

Dependencies Resolved

======================================================================================================
 Package Arch Version Repository Size
======================================================================================================
Installing:
 httpd x86_64 2.4.6–17.el7.centos.1 base 2.7 M

Transaction Summary
======================================================================================================
Install 1 Package

Total download size: 2.7 M
Installed size: 9.3 M
Is this ok [y/d/N]: y
Downloading packages:
httpd-2.4.6–17.el7.centos.1.x86_64.rpm | 2.7 MB 00:00:01 
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
 Installing : httpd-2.4.6–17.el7.centos.1.x86_64 1/1 
 Verifying : httpd-2.4.6–17.el7.centos.1.x86_64 1/1

Installed:
 httpd.x86_64 0:2.4.6–17.el7.centos.1

Complete!
[root@server ~]# service httpd restart
Redirecting to /bin/systemctl restart httpd.service

…. as you can see it did what I asked, but dropped some hints that I should have used systemctl restart httpd. What would systemctl status httpd give us …..

[root@server ~]# systemctl status httpd
httpd.service — The Apache HTTP Server
 Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled)
 Active: active (running) since Sun 2014–07–13 13:24:45 EDT; 4s ago
 Process: 21656 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=0/SUCCESS)
 Main PID: 21661 (httpd)
 Status: “Processing requests…”
 CGroup: /system.slice/httpd.service
 ├─21661 /usr/sbin/httpd -DFOREGROUND
 ├─21663 /usr/sbin/httpd -DFOREGROUND
 ├─21664 /usr/sbin/httpd -DFOREGROUND
 ├─21665 /usr/sbin/httpd -DFOREGROUND
 ├─21666 /usr/sbin/httpd -DFOREGROUND
 └─21667 /usr/sbin/httpd -DFOREGROUND

Jul 13 13:24:45 server.domain.com systemd[1]: Starting The Apache HTTP Server…
Jul 13 13:24:45 server.domain.com systemd[1]: Started The Apache HTTP Server.

….. now thats a lot more useful that what serivce httpd status used to give.

Other highlights & changes

Version number

The initial release of CentOS 7.0 is actually 7.0–1406 (see the numbering part of this noticeexternal link )

New Kernel

CentOS 7.0–1406 ships with 3.10.0–123, which is alot better than the previous 2.6.x kernel which shipped with CentOS 6

FirewallD

CentOS now comes with FirewallD, I can’t say I have ever used it before so more readingexternal link is neededexternal link

XFS

XFS is now the default file system when you install, though DigitalOceanexternal link have stuck with ext4

Linux Containers

Docker (which I have written about hereexternal link , hereexternal link and hereexternal link ) is now fully support out of the box with no need to install EPELexternal link , in fact, at the time of writing the CentOS repo was more up-to-date than EPEL.

[root@server ~]# yum list | grep docker
docker.x86_64 0.11.1–22.el7.centos extras 
docker-registry.noarch 0.6.8–8.el7 extras 

Other software

Some changes to later software across the board, here are the highlights ……