Linux

Setting runlevel at boot

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Changing runlevel on a live system is fairly simple – as root simply type init 3 (or whatever runlevel you want).However, what if you need to specify a runlevel at boot time? Imagine there is something wrong with your X configuration that is stopping you from being able to log in, how do you force […]

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Installing Redhat in various ways

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There are multiple methods and options available when installing Redhat. Here are just a few options and how to perform them.VNC Insert the installation DVD and boot the system At the installation prompt, hit [TAB] to modify the boot options At the end of the boot command, enter vnc and hit enter to start the […]

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System Configuration and Management — Produce and deliver reports on system utilization (processor, memory, disk, and network)

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sar appears to be the tool to save the day here. Installed and running by default, the sysstat package contains tools that capture system performance throughout the day, and automatically summarizes it for you. Generating utilization reports is then a simple matter of knowing the right sar command to execute. If all else fails, simply […]

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NTP — Synchronize time using other NTP peers

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The easiest way to configure NTP is to use the GUI. On the top bar, right-click the time and select Preferences Click Time Settings and the Set System Time Check the box Synchronize date and time over the network Edit the list of NTP servers and click OK Alternatively, you can execute system-config-date to go […]

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SSH — Configure key-based authentication

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One of my favorite things to do when managing Linux systems is to configure key-based authentication. This allows me to connect to multiple systems via scripts without have to re-authenticate every time. A decent walkthrough is available at http://linuxproblem.org/art_9.htmlScenario: You are user A on host A, and you want to log onto host B as […]

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DNS — Configure a caching-only name server to forward DNS queries

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I am not sure what the difference si between forwarding queries and caching queries – they both forward to another location. There is a good walkthrough of setting up a chaching nameserver at http://www.redhat.com/magazine/025nov06/features/dns/ Install the needed components yum install bind bind-utils bind-libs bind-chroot caching-nameserver copy /etc/named.conf to /var/named/chroot/etc/edit /var/named/chroot/etc/named.conf Change listen-on port from 127.0.0.1; […]

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NFS — Provide network shares suitable for group collaboration

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Restricting access to NFS shares can be done by restricting firewall access (iptables), or by configuring the /etc/exports file. The /etc/exports file can restrict access to a single machine, a wildcard, or an IP network.It all starts with installing and starting NFS yum install nfs-utils rpcbind service nfs start service rpcbind start Restricting to a […]