When installing a package, i get following error
Protected multilib versions: 1:systemd-libs-219-78.el7.cloudlinux.i686 != 1:systemd-libs-219-78.el7_9.2.cloudlinux.x86_64
To fix, remove the conflicting package with
rpm -e --nodeps --justdb systemd-libs
RedHat, parent company of CentOS Linux announce it will stop supporting CentOS 8, the latest version of CentOS. CentOS is build from the source code RHEL, making a free version of stable and well-tested enterprise ready RHEL Linux. CentOS 7 will keep getting security updates until it reaches End Of Life June 30th, 2024. For Red Hat, maintaining CentOS wont help with their business. Now they don’t need to maintain CentOS, this will force many users to pay for Red Hat Enterprise Linux (RHEL).
The new version of CentOS known as CentOS Stream is a rolling release. It will be used as a staging version of RHEL. Red Hat expect CentOS Stream to be stable and allow community participation as users will be able to contribute to CentOS Steam. With CentOS, community contribution was limited because it was a copy of RHEL.
CentOS is populary used in web hosting servers as cpanel only supposed RHEL based Linux. With death of CentOS 8, cpanel have announced they will accelerate investment in development efforts to support additional operating systems. cPanel will suport Ubuntu LTS and expect to deliver a production-ready version in late 2021. After Ubuntu LTS, they will look into supporting Debian. Ubuntu is very popular with Cloud Servers as it come with latest software compared to CentOS. With many developers already using Ubuntu on their Desktop, supporting Ubuntu is wise decision by cpanel.
With CentOS 8 unexpected demise, many users will be looking for alternative OS. This opens up market for next CentOS clone.
CentOS co-founder, Gregory Kurtzer announced he will be releasing his own Red Hat Enterprise Linux (RHEL) replacement Rocky Linux. No ETA on release date yet.
You can join discussion on their reddit.com/r/RockyLinux/
Igor Seletskiy, CloudLinux CEO and founder said they will make their own RHEL patch to patch compatible Open Source Linux – Project Lenix.
CloudLinux is a CentOS based commerical Linux, that is popular amoung web hosting providers as it allow resource limit per user and user isolation with CageFS. They also have support for kernel update with out reboot.
CloudLinux will be investing more than a million dollar into Project Lenix. CentOS 8 users will be able to convert into Project Lenix or CloudLinux easily with out reboot. In the announcement Igor Seletskiy said “Red Hat’s announcement has left users looking for an alternative with all that CentOS provides and without the disruption of having to move to alternative distributions. We promise to dedicate the resources required to Project Lenix that will ensure impartiality and a not-for-profit community initiative. CloudLinux already has the assets, infrastructure, and experience to carry out the mission, and we promise to be open about the process of developing Project Lenix”.
See CentOS
When i run yum update on a CentOS 6 server, i get error “Invalid release/repo/arch combination/”.
This error is due to CentOS reaching its End Of Life and no longer supported.
What you need to do is upgrade your server to the latest supported CentOS versions like CentOS 7 or CentOS 8. Converting to Oracle Linux 6 is another option, it is binary compatible with CentOS/RHEL 6, offers extended support until Jun 2024 and Indefinite Sustaining Support. If you want to convert CentOS 6 to Oracle Linux, see How to Migrate CentOS to Oracle Linux.
If you just need to fix the error, you need to go through each .repo file in the folder
/etc/yum.repos.d/
Comment out lines like
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra
Replace it with centos 6 vault repo URL
baseurl=https://vault.centos.org/centos/$releasever/os/$basearch/
You can find modified yum repository files at
https://github.com/serverok/centos6-repo
You can replace your existing repository files inside /etc/yum.repos.d folder with files in the above git repository with following commands.
cd /etc mv yum.repos.d yum.repos.d-old git clone https://github.com/serverok/centos6-repo.git yum.repos.d
If you get git not found error, you may need to manually download files from the repo and place in the directory /etc/yum.repos.d/.
After this, you will be able to update your system. If you have any other repo installed, you can copy it from yum.repos.d-old folder to make it active again.
Here is the updated CentOS-Base.repo file
https://raw.githubusercontent.com/serverok/centos6-repo/main/CentOS-Base.repo
# CentOS-Base.repo # # The mirror system uses the connecting IP address of the client and the # update status of each mirror to pick mirrors that are updated to and # geographically close to the client. You should use this for CentOS updates # unless you are manually picking other mirrors. # # If the mirrorlist= does not work for you, as a fall back you can try the # remarked out baseurl= line instead. # # [base] name=CentOS-$releasever - Base baseurl=https://vault.centos.org/centos/$releasever/os/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #released updates [updates] name=CentOS-$releasever - Updates baseurl=https://vault.centos.org/centos/$releasever/updates/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #additional packages that may be useful [extras] name=CentOS-$releasever - Extras baseurl=https://vault.centos.org/centos/$releasever/extras/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #additional packages that extend functionality of existing packages [centosplus] name=CentOS-$releasever - Plus baseurl=https://vault.centos.org/centos/$releasever/centosplus/$basearch/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #contrib - packages by Centos Users [contrib] name=CentOS-$releasever - Contrib baseurl=https://vault.centos.org/centos/$releasever/contrib/$basearch/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
After updating yum repo, run
yum clean all yum makecache
Xfce is a lightweight linux desktop environment. You can install Xfce on a remote server or virtual machine, connect to it using VNC to use it as a desktop.
To install Xfce, enable EPEL repo
yum install -y epel-release
Install Xfce
yum groupinstall Xfce
You can see other groups available with command “yum grouplist”.
Insall vnc server
yum install -y tigervnc-server
We need to create a normal linux user to use with Xfce. Using it as root is not recommended.
To create user, run
useradd -m --shell /bin/bash serverok
Replace “serverok” with whatever username you want to use.
Change to the user we created before
su - serverok
To create initial vnc config files and set password, run
vncserver -fg
We used -fg option to keep vncserver in forground. vcnserver will ask you to set password, this will be used to connect to VNC server.
When i run “vncserver -fg” on CentOS, it exited with error. If it keep running, press CTRL+C to stop vnc server.
If you run with out -fg option, you can stop vnc server with command
vncserver -kill :1
Edit file
vi /home/serverok/.vnc/xstartup
Replace contents of this file with following
#!/bin/sh unset SESSION_MANAGER unset DBUS_SESSION_BUS_ADDRESS /etc/X11/xinit/xinitrc /bin/startxfce4
Now you can start vncserver manually with command
vncserver -fg
You will be able to connect to VNC server with YOUR_SERVER_IP:1
Following need to be done as user root.
Edit file
vi /usr/lib/systemd/system/[email protected]
Find
ExecStart=/usr/bin/vncserver_wrapper%i
Replaced with
ExecStart=/usr/bin/vncserver_wrapper serverok %i
reload systemctl
systemctl daemon-reload
Enable vncserver to start on boot
systemctl enable vncserver@:1.service
Start vncserver
systemctl start vncserver@:1.service
You need to open VNC port in firewall. vnc ports start at 5900, for :1, it will be 5901.
[root@centos7 ~]# netstat -lntp | grep vnc tcp 0 0 0.0.0.0:5901 0.0.0.0:* LISTEN 1951/Xvnc tcp 0 0 0.0.0.0:6001 0.0.0.0:* LISTEN 1951/Xvnc tcp6 0 0 :::5901 :::* LISTEN 1951/Xvnc tcp6 0 0 :::6001 :::* LISTEN 1951/Xvnc [root@centos7 ~]#
If you are using firewalld, you can open port 5901 with
firewall-cmd --zone=public --add-port=5901/tcp firewall-cmd --zone=public --add-port=5901/tcp --permanent
firewall-cmd command is run 2 times as first command only make changes in current session. second command with –permanent option make changes permanent, but that only happens after you reload firewalld or reboot server. Running command 2 times make the changes permanent and apply changes to current session.
See VNC, Remote Desktop
To disable SELinux
sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config setenforce 0
edit file
vi /etc/selinux/config
Find
SELINUX=enforcing
Replace with
SELINUX=disabled
Reboot the server with
reboot
You can disable selinux for current session by running command
setenforce 0
See SELinux
To install the latest MariaDB on the CentOS server, go to
https://mariadb.org/download/?t=repo-config
On this page, select CentOS, then select your CentOS version and MariaDB version you need.
Below you will see instructions for your specific version of CentOS.
CentOS 7 by default provide MariaDB 5.5. To install MariaDB 10.5
Create file
vi /etc/yum.repos.d/MariaDB.repo
Add
# MariaDB 10.5 CentOS repository list - created 2020-11-05 08:27 UTC # http://downloads.mariadb.org/mariadb/repositories/ [mariadb] name = MariaDB baseurl = http://yum.mariadb.org/10.5/centos7-amd64 gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB gpgcheck=1
Now you can install MariDB with command
yum install MariaDB-server MariaDB-client
To start MariaDB, run
systemctl start mariadb
You can replace start with stop/restart/status. To auto start MariaDB on boot, run
systemctl enable mariadb
See MySQL
Create init file.
touch /etc/rc.d/init.d/prometheus chmod 755 /etc/rc.d/init.d/prometheus vi /etc/rc.d/init.d/prometheus
Add following
#!/bin/bash
#
# /etc/rc.d/init.d/prometheus
#
# Prometheus monitoring server
#
# chkconfig: 2345 20 80 Read
# description: Prometheus monitoring server
# processname: prometheus
# Source function library.
. /etc/rc.d/init.d/functions
PROGNAME=prometheus
PROG=/usr/hostonnet/prometheus/$PROGNAME
USER=prometheus
LOGFILE=/var/log/prometheus.log
DATADIR=/usr/hostonnet/prometheus/data
LOCKFILE=/var/run/$PROGNAME.pid
CONFIG_FILE=/usr/hostonnet/prometheus/prometheus.yml
ALERT_MGR_URL=localhost:9093
start() {
echo -n "Starting $PROGNAME: "
cd /usr/hostonnet/prometheus/
#daemon --user $USER --pidfile="$LOCKFILE" "$PROG -config.file $CONFIG_FILE -storage.local.path $DATADIR -alertmanager.url $ALERT_MGR_URL &>$LOGFILE &"
daemon --user $USER --pidfile="$LOCKFILE" "$PROG -config.file $CONFIG_FILE -storage.local.path $DATADIR &>$LOGFILE &"
echo $(pidofproc $PROGNAME) >$LOCKFILE
echo
}
stop() {
echo -n "Shutting down $PROGNAME: "
killproc $PROGNAME
rm -f $LOCKFILE
echo
}
case "$1" in
start)
start
;;
stop)
stop
;;
status)
status $PROGNAME
;;
restart)
stop
start
;;
reload)
echo "Sending SIGHUP to $PROGNAME"
kill -SIGHUP $(pidofproc $PROGNAME)
;;
*)
echo "Usage: service prometheus {start|stop|status|reload|restart}"
exit 1
;;
esac
groupadd -r prometheus useradd -r -g prometheus -s /sbin/nologin -d /usr/hostonnet/prometheus/ -c "prometheus Daemons" prometheus chown -R prometheus:prometheus /usr/hostonnet/prometheus/ chown prometheus:prometheus /var/log/prometheus.log
chkconfig --add prometheus chkconfig prometheus on
Verify it is enabled
[root@backup ~]# chkconfig --list | grep prome prometheus 0:off 1:off 2:on 3:on 4:on 5:on 6:off [root@backup ~]#
“3:on” will start prometheus on run level 3, that is normal boot.
Start Prometheus
[root@backup ~]# service prometheus start Starting prometheus: [ OK ] [root@backup ~]#
To install PHP 5.6 on CentOS 7, enable EPEL repo and remi repo
yum install epel-release -y rpm -ivh https://rpms.remirepo.net/enterprise/remi-release-7.rpm
Install yum-utils and enable remi-php56 repo
yum install yum-utils yum-config-manager --enable remi-php56
Install PHP 5.6 with
yum install -y php php-bcmath php-cli php-common php-devel php-gd \
php-imap php-intl php-json php-ldap php-lz4 php-mbstring php-mysqlnd \
php-soap php-intl php-opcache php-xml php-pdo
yum install PKG_NAME
yum remove
Example for installing php and GD
yum install php php-gd
When you need to update all install software, run
yum update
List all available software
yum list available yum list available "software-name"
List all installed software
yum list installed
See yum
EPEL (Extra Packages for Enterprise Linux) provide additional software for CentOS and RHEL.
You can find more information about EPEL at
http://fedoraproject.org/wiki/EPEL
On CentOS 7/8, you can enable EPEP repo with command
yum instal epel-release
Or just download rpm package from the site and install.
RHEL/CentOS 6:
yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
RHEL/CentOS 7:
yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
RHEL/CentOS 8:
yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
To install elasticsearch, first install java
yum -y install java-1.8.0-openjdk
Import key
rpm --import https://artifacts.elastic.co/GPG-KEY-elasticsearch
Create file
vi /etc/yum.repos.d/elasticsearch.repo
Paste following
[elasticsearch] name=Elasticsearch repository for 7.x packages baseurl=https://artifacts.elastic.co/packages/7.x/yum gpgcheck=1 gpgkey=https://artifacts.elastic.co/GPG-KEY-elasticsearch enabled=0 autorefresh=1 type=rpm-md
Install elasticsearch
yum install --enablerepo=elasticsearch elasticsearch
Set elastic search to start on boot
systemctl enable elasticsearch
To start/stop/status
systemctl stop elasticsearch.service systemctl start elasticsearch.service systemctl status elasticsearch.service
To see logs
tail -f /var/log/elasticsearch/elasticsearch.log
ElasticSearch runs on port 9200
[root@server ~]# netstat -lntp | grep java tcp6 0 0 127.0.0.1:9200 :::* LISTEN 1289/java tcp6 0 0 ::1:9200 :::* LISTEN 1289/java tcp6 0 0 127.0.0.1:9300 :::* LISTEN 1289/java tcp6 0 0 ::1:9300 :::* LISTEN 1289/java [root@server ~]#
If you get error starting elasticsearch, check Elasticsearch failed to start on CentOS 7
If you have a previous installation, make sure you delete left over files before you install differnt version of elasticsearch. I removed following files/folders when i had to downgrade elasticsearch.
/etc/sysconfig/elasticsearch.rpmsave /var/lib/elasticsearch /var/log/elasticsearch
See elasticsearch