cloud engineer
Here’s the installation instructions for OpenJDK 8.
For Fedora, Redhat and Oracle Linux.
yum install java-1.8.0-openjdk |
yum install java-1.8.0-openjdk
For Debian and Ubuntu.
apt-get install openjdk-8-jre |
apt-get install openjdk-8-jre
To see if the packages (symbolic links) are there, they can be found in /etc/alternatives/, at least in Redhat 7.
ls -l /etc/alternatives/ |
ls -l /etc/alternatives/
Here are the commands to start, stop, enable and get the status of Apache on RHEL and CentOS.
systemctl enable httpd # enable on bootup systemctl status httpd # get status systemctl start httpd # start systemctl stop httpd # stop systemctl restart httpd # restart |
systemctl enable httpd # enable on bootup systemctl status httpd # get status systemctl start httpd # start systemctl stop httpd # stop systemctl restart httpd # restart
Here’s how to upgrade to OpenSSL 1.1 on Redhat/Centos.
# check openssl version yum info openssl # download and install cd /usr/local/src wget https://www.openssl.org/source/openssl-1.0.2-latest.tar.gz tar -zxf openssl-1.0.2-latest.tar.gz # compile cd openssl-1.0.2a ./config make make test make install # update softlink mv /usr/bin/openssl /root/ ln -s /usr/local/ssl/bin/openssl /usr/bin/openssl # verify new version openssl version |
# check openssl version yum info openssl # download and install cd /usr/local/src wget https://www.openssl.org/source/openssl-1.0.2-latest.tar.gz tar -zxf openssl-1.0.2-latest.tar.gz # compile cd openssl-1.0.2a ./config make make test make install # update softlink mv /usr/bin/openssl /root/ ln -s /usr/local/ssl/bin/openssl /usr/bin/openssl # verify new version openssl version
Here’s how to disable plugin in Yum repos.
# check which plugins are enabled yum repolist # disable plugins yum update --disableplugin=product-id,subscription-manager # check agin yum repolist |
# check which plugins are enabled yum repolist # disable plugins yum update --disableplugin=product-id,subscription-manager # check agin yum repolist
If that doesn’t work, check the individual config files of each plugin.
cd /etc/yum/pluginconf.d/ vim product-id.conf vim subscription-manager.conf |
cd /etc/yum/pluginconf.d/ vim product-id.conf vim subscription-manager.conf
Disable it.
[main] enable=0 |
[main] enable=0
To see which disk is available for swap disk use.
lsblk blkid df -Th |
lsblk blkid df -Th
Format the disk.
fdisk /dev/xvda |
fdisk /dev/xvda
Create a swap disk.
sudo mkswap -f /dev/xvda sudo swapon -s /dev/xvda # or sudo swapon /dev/xvda |
sudo mkswap -f /dev/xvda sudo swapon -s /dev/xvda # or sudo swapon /dev/xvda
Check if swap disk is available.
lsblk free -h cat /proc/swaps cat /proc/meminfo swapon -s top vmstat vmstat 1 5 |
lsblk free -h cat /proc/swaps cat /proc/meminfo swapon -s top vmstat vmstat 1 5