MkWikiEnSysOp: Updated LXC

2020-05-31T15:25:03Z

Updated LXC

← Older revision		Revision as of 15:25, 31 May 2020
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	systemctl restart vnstat		systemctl restart vnstat

	=== Installing LXC ===		=== LXC ===

			==== Installing LXC ====

	Linux containers can be used when installing these packages:		Linux containers can be used when installing these packages:
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	There is a [http://e-syslog.blogspot.de/2014/12/lxc-container-libvirt-on-centos-7.html how to] that explains how LXC can be installed on CentOS when using libvirt and friends.		There is a [http://e-syslog.blogspot.de/2014/12/lxc-container-libvirt-on-centos-7.html how to] that explains how LXC can be installed on CentOS when using libvirt and friends.

			==== Creating a CentOS container ====

			lxc-create -t download -n centos8c1 -- -d centos -r 8 -a amd64

	=== Installing recent kernel ===		=== Installing recent kernel ===

MkWikiEnSysOp: +CentOS 8

2020-05-31T15:20:59Z

+CentOS 8

← Older revision		Revision as of 15:20, 31 May 2020
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	cat /proc/net/dev		cat /proc/net/dev

			The network configuration is saved in /etc/sysconfig/network-scripts: each network interface has got a file ifcfg-'''name''', for example "ifcfg-enp0s3" for an ethernet adapter. In such a file, "ONBOOT=yes" can be set, so the interface will be brought up at boot. See also: [https://www.centos.org/docs/5/html/5.1/Deployment_Guide/s1-networkscripts-files.html Network Configuration Files]

			==== CentOS 7 ====

	After that, install some basic network utilities:		After that, install some basic network utilities:
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	systemctl start ntpd		systemctl start ntpd

	The network configuration is saved in /etc/sysconfig/network-scripts: each network interface has got a file ifcfg-'''name''', for example "ifcfg-enp0s3" for an ethernet adapter. In such a file, "ONBOOT=~~yes" can be~~ set~~, so the interface will be brought up at boot. See also: [https://www.centos.org/docs/5/html/5.~~1~~/Deployment_Guide/s1-networkscripts-files~~.~~html Network Configuration Files]~~		==== CentOS 8 ====

			timedatectl set-ntp 1

			This activates time synchronisation.

	== Software ==		== Software ==

MkWikiEnSysOp: 13 revisions imported

2018-06-28T17:19:37Z

13 revisions imported

New page

== Introduction ==

CentOS is a GNU/Linux operating system with long term support (10 years after release). It is a rebuild of Red Hat Enterprise Linux. Some packages in the distribution are already 1 to 2 years old when a new CentOS release is made. That means you don't get the most current software, but the software you get is quite mature. You can assume that most of the bugs in every software in CentOS have been found and fixed already. Anyway, there's sometimes a route to newer software, for example, very new kernels can be installed.

Just one comparison:
* '''Linux kernel:''' When CentOS 7 was released on 2014-07-07, it was shipped with Linux 3.10. At this time, this kernel was already one year old (released by the end of June, 2013). Ubuntu 14.04, which was released in April, 2014, already contained Linux 3.13.

[http://distrowatch.com/table.php?distribution=centos CentOS@Distrowatch]

== Setting up ==

=== Setting up network and network tools ===

If there is no network connectivity, the network might be unconfigured. Get an IP address by issuing

dhclient ''enp0s3''

Adjust ''enp0s3'' to your needs!

If you don't know the names of your network interfaces, this command will tell them to you:

cat /proc/net/dev

After that, install some basic network utilities:

yum install ntp ntpdate ntp-doc net-tools

The "net-tools" package includes "netstat" and "ifconfig".

These commands enable and start the network time daemon:

systemctl enable ntpd
systemctl start ntpd

The network configuration is saved in /etc/sysconfig/network-scripts: each network interface has got a file ifcfg-'''name''', for example "ifcfg-enp0s3" for an ethernet adapter. In such a file, "ONBOOT=yes" can be set, so the interface will be brought up at boot. See also: [https://www.centos.org/docs/5/html/5.1/Deployment_Guide/s1-networkscripts-files.html Network Configuration Files]

== Software ==

CentOS uses the <code>yum</code> command to manage its packages. The most important commands are:

yum install ''package''
yum remove ''package''
yum list
yum provides ''command''
yum search ''package''

Many more options can be seen in its man page.

Comparing to "apt" in Debian/Ubuntu, yum is slightly slower than apt, because at every start it outputs something like

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
base: artfiles.org
elrepo: nl.mirror.babylon.network
epel: nl.mirror.babylon.network
extras: ftp.plusline.de
updates: mirror.dataone.nl

However, I would not perceive that as a problem. Until now, yum never made troubles and did a fantastic job.

=== Install EPEL ===

To do some advanced things, like vnstat or lxc, install '''epel-release''':

yum install epel-release

=== Enabling automatic updates ===

yum -y install yum-cron
systemctl enable yum-cron
systemctl start yum-cron

It is recommended to review the settings using

nano /etc/yum/yum-cron.conf

=== Installing and configuring vnstat ===

yum install vnstat
systemctl enable vnstat
systemctl start vnstat

Then, for every interface that <code>ifconfig | grep "RUNNING"</code> reports, create the database by using

sudo -u vnstat vnstat -i -u ''iface''

It is important to run this as user "vnstat" so the database files in /var/lib/vnstat/ have the right permissions (rw-r--r-- or 644) and owner (vnstat.vnstat). The daemon that updates the database files runs as user "vnstat" and if the files are not writeable by this user, the daemon cannot do its job.

After every interface added, the daemon must be restarted so it is notified about that change:

systemctl restart vnstat

=== Installing LXC ===

Linux containers can be used when installing these packages:

yum install lxc lxc-templates debootstrap perl libvirt lxc-extra
systemctl enable lxc
systemctl start lxc
systemctl start libvirtd

[http://www.tecmint.com/install-create-run-lxc-linux-containers-on-centos/ Credits]

'''debootstrap''' is for installing Debian and operating systems based on it (like Ubuntu). '''lxc-extra''' contains the lxc-ls command (which is actually just a python script).

There is a [http://e-syslog.blogspot.de/2014/12/lxc-container-libvirt-on-centos-7.html how to] that explains how LXC can be installed on CentOS when using libvirt and friends.

=== Installing recent kernel ===

rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm
yum --enablerepo=elrepo-kernel install kernel-ml

[https://www.ostechnix.com/install-linux-kernel-4-4-5-centos-ubuntu/ Credits]

[[Category:Linux]]

CentOS - Revision history

MkWikiEnSysOp: Updated LXC

MkWikiEnSysOp: +CentOS 8

MkWikiEnSysOp: 13 revisions imported