Here are some notes for installing and configuring Oracle Linux.
None of them are particularly clever, I just often forget the exact commands.
Installation
Disable Predictive Network Interface Names
The WSC-ME does not support Predictable Network Interface Names.
To disable it, during installation, upon the initial install screen, press TAB, and add the following parameter to the boot parameters:
net.ifnames=0
Example:
Minimum Install
For Oracle products, always go with the minimum install (default).
Remember to:
- Set the host name
- Configure each network interface to "Automatically connect to this network when it is available"
- Set the timezone and enable Network Time
- Select the installation drive
- Set root password
Network Installation
For Oracle 7: http://public-yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/
For Oracle 8: http://yum.oracle.com/repo/OracleLinux/OL8/baseos/latest/x86_64
Oracle YUM Server
Certain applications (like Docker) require authentication.
docker login container-registry.oracle.com
Screen Blanking
Screen blanking (on VMs) really annoys me. To turn of screen blanking from the console (not ssh):
setterm -powersave off -blank 0
Common User Modifications
The simplest way to give a user 'sudo' privileges is to add them to the 'wheel' group.
usermod -aG wheel <user>
Entering passwords every time I use 'sudo' annoys me.
Type 'visudo' to edit the 'sudoers' file. Comment out the regular line and uncomment the NOPASSWD line.
## Allows people in group wheel to run all commands
#%wheel ALL=(ALL) ALL
## Same thing without a password
%wheel ALL=(ALL) NOPASSWD: ALL
Typing a password when using SSH also annoys me. From your workstation, run the command:
ssh-copy-id <user>@<hostname>
If you like, you can disable passwords (in favor of security keys) by editing /etc/ssh/sshd_config.
Change PermitRootLogin and PasswordAuthentication.
Here's a quick command to do it:
sudo sed -i --follow-symlinks 's/#PermitRootLogin yes/PermitRootLogin no/g' /etc/ssh/sshd_config
sudo sed -i --follow-symlinks 's/^PasswordAuthentication yes$/PasswordAuthentication no/g' /etc/ssh/sshd_config
YUM
Before using 'yum', always run an update:
sudo yum -y update
Oracle comes with some interesting repositories. Take a look at "/etc/yum.repos.d" for a list of repositories.
To enable them, type:
sudo yum -y install yum-utils
sudo yum-config-manager --enable <repository>
Open VM Tools
If needed, install Open VM Tools.
sudo yum -y install open-vm-tools
SELinux
It must have a purpose, but I find it annoying. It can be disabled like this:
sudo setenforce 0
sudo sed -i --follow-symlinks 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/sysconfig/selinux
Firewall
I also find the built-in firewall annoying.
To disable it:
sudo systemctl stop firewalld
sudo systemctl disable firewalld
However, if you would like to use it properly, here are some examples to give you ideas:
sudo firewall-cmd --add-port=1521/tcp --permanent
sudo firewall-cmd --add-port=5060/udp --permanent
sudo firewall-cmd --zone=public --permanent --add-service=http
sudo firewall-cmd --zone=public --permanent --add-service=https
sudo systemctl restart firewalld
Random Numbers
Headless servers have a hard time producing random numbers. This will slow WebLogic and other applications.
To check your entropy:
cat /proc/sys/kernel/random/entropy_avail
If the number is less than 1000, install 'haveged':
sudo yum-config-manager --add-repo https://yum.oracle.com/repo/OracleLinux/OL8/developer/EPEL/x86_64
sudo yum -y install haveged
sudo systemctl enable haveged.service
sudo systemctl start haveged
Kernel Parameter Tuning
Here's a quick way to tune kernel parameters:
yum -y install oracle-database-preinstall-19c
Wireshark
Getting this error?
Install drivers:
sudo dnf install -y mesa-dri-drivers
Getting this error?
Create an environment variable, like so: