Java 8 installation on Fedora 14

1. Download Java SDK/JRE from Oracle: http://www.oracle.com/technetwork/java/javase/downloads/server-jre8-downloads-2133154.html. (I selected the server version).
2. Extract the files into /usr/local/java. (I created the java directory).
3. Use the alternatives program to create the necessary links:
• [root@Fedora-test ~]# alternatives --install /usr/bin/java java /usr/local/java/jdk1.8.0_20/bin/java 20000
• Run the alternatives config command:

[root@Fedora-test ~]# alternatives --config java

Select the option for Java 8

• Test it:

[root@Fedora-test ~]# java -version
java version "1.8.0_20"
Java(TM) SE Runtime Environment (build 1.8.0_20-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.20-b23, mixed mode)

The following link was useful: http://www.dafoot.co.uk/index.php/menuitemcomputing/linux/101-fedora-12-alternatives-program-to-manage-java-runtimes-jdkjre

systemd-analyze - Analyze system boot-up performance

systemd-analyze may be used to determine system boot-up performance of the current boot.

systemd-analyze blame prints a list of all running units, ordered by the time they took to initialize.

SysVinit to Systemd Cheatsheet

http://fedoraproject.org/wiki/SysVinit_to_Systemd_Cheatsheet

Fedora Full List of Kernel Options

The full list of kernel options is in the file /usr/share/doc/kernel-doc-<version>/Documentation/kernel-parameters.txt, which is installed with the kernel-doc package.

Taken from:
https://fedoraproject.org/wiki/Common_kernel_problems#Getting_the_Full_List_of_Kernel_Options

Fedora 19 sytemctl

systemctl works with not only services but all other unit types, and is a valuable tool when monitoring or troubleshooting a system. It can list all known units, limit the results to a single unit type, show only failed units, or examine unit relationships. The table below shows some useful systemctl features and should help system administrators replace their old workflow in sysVinit.

systemctl command reference

sysVinit command	systemd command	Notes
service sshd start	systemctl start sshd.service	Used to start a service (not reboot persistent)
service sshd stop	systemctl stop sshd.service	Used to stop a service. (not reboot persistent)
service sshd restart	systemctl restart sshd.service	Used to start and stop a service.
service sshd reload	systemctl reload sshd.service	When supported, reloads the config file without interrupting pending operations.
service sshd condrestart	systemctl condrestart sshd.service	Restarts if the service is already running.
service sshd status	systemctl status sshd.service	Tells whether a service is currently running.
ls /etc/rc.d/init.d/	systemctl list-unit-files --type=service	Lists all available services.
chkconfig sshd on	systemctl enable sshd.service	Always run the service at this target (runlevel.)
chkconfig sshd off	systemctl disable sshd.service	Do not automatically run the service at this target (runlevel.)
chkconfig --list	systemctl list-units -t service --all	Print a table of available services and their status.
chkconfig sshd --list	ls /etc/systemd/system/*.wants/sshd.service	Lists the targets that will include the service.
chkconfig sshd --add	systemctl daemon-reload	Used when you create a service file or modify any configuration.
telinit 3	systemctl isolate multi-user.target	Move system into another target (change runlevels.)
[no comparable command]	systemctl show -p "Wants" multi-user.target	Lists units pulled in by a given target.
[no comparable command]	systemctl show -p "After" sshd.service	Shows dependent services and other targets.
[no comparable command]	systemd --test --system --unit=multi-user.target	Simulates booting the system to a given target
[no comparable command]	systemd-analyze plot > boot.svg	Generates a diagnostically useful graphical representation of the boot process.
ps xawf -eo pid,user,cgroup,args	systemd-cgls	Display control group process tree.

Network interfaces in Fedora 14

http://docs.fedoraproject.org/en-US/Fedora/14/html/Deployment_Guide/ch-Network_Interfaces.html

Configuring static network routes in Fedora 14

http://docs.fedoraproject.org/en-US/Fedora/14/html/Deployment_Guide/s1-networkscripts-static-routes.html

Show ports and the applications bound to them

#!/bin/bash

netstat -lntup \

| awk '/^(tcp|udp)/ {print substr($4, match($4, ":[^:]+$") + 1) "/" $1, substr($NF, 1, index($NF, "/") - 1)}' \

| while read PORT PID

do

        BIN=$(readlink /proc/$PID/exe)

        echo $PORT $PID $BIN

done

Show hardware info in Fedora

dmidecode -q
less /proc/cpuinfo
lspci
lsusb

Delete route in Fedora

route del -net 172.16.9.0 netmask 255.255.255.0 eth3

Yum groups and repositories

Yum supports the group commands

• grouplist
• groupinfo
• groupinstall
• groupremove
• groupupdate

Groups are read from the "group" xml metadata that is optionally available from each repository. If yum has no repositories which support groups then none of the group operations will work.

• grouplist

  yum grouplist [hidden]
  

This will list the installed and available groups for your system in two separate lists. If you pass the optional 'hidden' argument then all of the groups which are set to 'no' in the group xml tag.

• groupinfo

  yum groupinfo groupname
  

This will give you detailed information for each group including: description, mandatory, default and optional packages.

• groupinstall, groupupdate

  yum groupinstall groupname
       yum groupupdate groupname
  

Despite their differing names both of these commands perform the same function. They will attempt to install/update all of the packages in the group that are of the types 'default' or 'mandatory' (by default). (To change this types of packages edit the value of the group_package_types option in yum.conf.) And they will install any additional dependencies needed by any of the installing/updating packages.

• groupremove

  yum groupremove groupname
  

This will remove all packages, of any type, in the named group. It will also remove any package that depends on any of these packages.

Static routes after restart/reboot in Fedora/RedHat/CentOS

Static routing is the term used to refer to the manual method used to set up routing. An administrator enters routes into the router using configuration commands. This method has the advantage of being predictable, and simple to set up. It is easy to manage in small networks but does not scale well.

Question: How can I save static routes I set up in my Fedora/RedHat/CentOS Linux after I reboot server?

Answer: In Fedora Linux (or RedHat, CentOS) you can set up static routes for certain network interface (for example eth1) by editing file /etc/sysconfig/network-scripts/route-eth1.

For example, you have to save static route added by the following command:

route add -net 192.168.0.0 netmask 255.255.255.0 gw 192.168.100.1 dev eth1

To do it, just add the following line to /etc/sysconfig/network-scripts/route-eth1:

ADDRESS0=192.168.0.0
NETMASK0=255.255.255.0
GATEWAY0=192.168.100.1

The alternate way of doing it is to put the routes in /etc/sysconfig/static-routes. So the above route would like this like in the static-routes file:

any net 192.168.0.0 netmask 255.255.255.0 gw 192.168.100.1

Where any is specified above you can also set specific interfaces (such as eth1).

Here is the part /etc/init.d/interfaces code:

# Add non interface-specific static-routes.
if [ -f /etc/sysconfig/static-routes ]; then
grep "^any" /etc/sysconfig/static-routes | while read ignore args ; do
/sbin/route add -$args
done
fi

Looks like any must be at the beginning of each line in /etc/sysconfig/static-routes.

/usr/share/doc/initscripts-${VERSION}/sysconfig.txt is a good place to look for these things as well