This post will guide you how to use yum-cron to update system under CentOS/RHEL Linux. How do I configure yum automatic updates with yum-cron tool in Linux. How to set yum updates with yum-cron.
What is Yum-cron?
The yum-cron is an optional package starting from RHEL 6/CentOS 6 and it is a yum plugin.
yum-cron is a simple way to call yum commands from cron. It provides configuration to keep repository metadata up to date, and to check for, download, and apply updates.
Install yum-cron
If you want to setup automatic yum updates with yum-cron, you need to install the yum-cron package firstly. Type the following command:
# yum install yum-cron
Outputs:
[root@devops ~]# yum install yum-cron Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: centos.ustc.edu.cn * extras: mirrors.huaweicloud.com * updates: mirrors.aliyun.com Resolving Dependencies --> Running transaction check ---> Package yum-cron.noarch 0:3.4.3-158.el7.centos will be installed --> Finished Dependency Resolution Dependencies Resolved ================================================================================ Package Arch Version Repository Size ================================================================================ Installing: yum-cron noarch 3.4.3-158.el7.centos base 63 k Transaction Summary ================================================================================ Install 1 Package Total download size: 63 k Installed size: 51 k Is this ok [y/d/N]: y Downloading packages: yum-cron-3.4.3-158.el7.centos.noarch.rpm | 63 kB 00:00 Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : yum-cron-3.4.3-158.el7.centos.noarch 1/1 Verifying : yum-cron-3.4.3-158.el7.centos.noarch 1/1 Installed: yum-cron.noarch 0:3.4.3-158.el7.centos Complete!
Start Yum-cron Service
After installed yum-cron package, you need to start the yum-cron service.
For CentOS 7/RHEL 7 Linux:
# systemctl start yum-cron.service
Outputs:
[root@devops ~]# systemctl start yum-cron [root@devops ~]# systemctl status yum-cron yum-cron.service - Run automatic yum updates as a cron job Loaded: loaded (/usr/lib/systemd/system/yum-cron.service; enabled; vendor preset: disabled) Active: active (exited) since Sun 2018-09-16 11:14:36 EDT; 2s ago Process: 3579 ExecStart=/bin/touch /var/lock/subsys/yum-cron (code=exited, status=0/SUCCESS) Main PID: 3579 (code=exited, status=0/SUCCESS) Sep 16 11:14:36 devops systemd[1]: Starting Run automatic yum updates as a ..... Sep 16 11:14:36 devops systemd[1]: Started Run automatic yum updates as a c...b. Hint: Some lines were ellipsized, use -l to show in full.
For CentOS 6/RHEL 6 Linux:
Type the following command:
# service yum-cron start
Configure Yum-cron
You need to edit the configuration file of yum-cron, and it is located in /etc/yum/yum-cron.conf.
For CentOS 6/RHEL 6 Linux:
Adding the below line into the file:
MAILTO=osetc@gmail.com YUM_PARAMETER=kernel* http*
Note: The YUM_PARAMETER variable is used to exclude packages using yum-cron to update the system. So it won’t update the kernel and http packages.
For CentOS 7/RHEL 7 Linux:
Adding the below line into the file: MAILTO=osetc@gmail.com exclude=kernel* http*
Then save and close the file.
You still need to restart the yum-cron service.
Type the following command:
# systemctl restart yum-cron
Or
# service yum-cron restart
By default, the yum-cron tool will be run daily based on the yum-daily.cron job. Let’s see this cron job.
[root@devops ~]# cat /etc/cron.daily/0yum-daily.cron #!/bin/bash # Only run if this flag is set. The flag is created by the yum-cron init # script when the service is started -- this allows one to use chkconfig and # the standard "service stop|start" commands to enable or disable yum-cron. if [[ ! -f /var/lock/subsys/yum-cron ]]; then exit 0 fi # Action! exec /usr/sbin/yum-cron
If you want to get more information about the yum-cron, just see the man page of yum-cron.
# man yum-cron