Linux - Everyday DevOps

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Topics such as installing Kubernetes tools on Linux with Homebrew, using Vim and Tmux, upgrading Ubuntu, configuring OpenSUSE for Vagrant, managing Nginx access settings, troubleshooting SELinux permissions, and setting up services like VNC, NTP, LDAP, PXE, and VMware. The focus is on practical, real-world guidance for system administrators and developers working in Linux-based environments.

Setup Kubernetes Admin on Linux with Brew

Setup Kubernetes Admin on Linux with Brew

My goal for the year was to transition from a Macbook Pro to an iPad Pro for most of my development tasks, which required migrating my kubernetes admin tools to function in the cloud. To accomplish this, I’m using several AWS EC2 instances running Ubuntu. Here, I will detail

VIM & Tmux Basics

VIM & Tmux Basics

Why? Vi (vim) is the only editor you can be guaranteed to have on a Linux machine. If you ever have to log into a server or container to see what's going on or make changes, this will be all you'll have. It will save your

Upgrading from Ubuntu 12.10 to 14.04

Upgrading from Ubuntu 12.10 to 14.04

It seems that a few of my instances in AWS were originally set up using Ubuntu 12.10. I don't know how that happened, but anyway, now that 12.10 is no longer supported, you can't just upgrade. So the solution is to use the old.

OpenSUSE 11.1 for Vagrant

OpenSUSE 11.1 for Vagrant

Seems that last week I needed an openSUSE 11.1 VM to test out some chef scripts. Vagrant Cloud which is a great place to find Vagrant VMs didn't have one, so I decided to create one. Start first by downloading and installing packer an incredible tool for

Nginx Deny IP

This is a quick way to deny an ip address accessing your nginx server. Create a new file in /etc/nginx/conf.d called blockips.conf Add the following to the file: deny <bad ip>; Then restart nginx. The log file will now show 403's for

Fixing SELinux Content in a HTML directory

Unable to access web files in a directory under the /var/www/html becuase of a 403 forbidden might be a context problem. ProblemGetting a 403 forbidden error message when accessing a new file or directory in /var/www/html. Check /var/log/messages to see if there are any:

Setting up VNCServer

How to setup vncserver on a linux machine to run gnome or kde. InitializeStartup vncserver for the first time on port 5910 (:10) and set the password. [root@localhost ~]# vncserver :10 You will require a password to access your desktops. Password: Verify: xauth: creating new authority file /root/.Xauthority New

Setting up ntpd

A quick way to setup ntpd to set the system and hardware clock On a Redhat system (Redhat, CentOS, Fedora or Oracle Linux) edit the /etc/sysconfig/ntpd file: * Change:SYNC_HWCLOCK=no to SYNC_HWCLOCK=yes * Add: -x to OPTIONS so that the clock will be set every time

Setup LDAP with Openfiler

How to configure LDAP so that Windows shares will work with Openfiler. Configure LDAP for SambaThe assumption is that LDAP is already up and running with user accounts with the posixAccount object classes. Add samba.schema to LDAPCopy samba.schema from /usr/share/doc/samba-3.0.10/LDAP to /etc/

Setting up PXE

PXE is a great way to install linux on a server without the need of have a CD Rom. The following is a good starting point: http://www.redhat.com/docs/manuals/enterprise/RHEL-3-Manual/sysadmin-guide/ch-pxe.html

Disk Performance

Using hdparm to measure a hard disks performance. To measure the current performance of your disk run: hdparm -tT /dev/sda You will get something like: /dev/sda: Timing cached reads: 896 MB in 2.01 seconds = 446.06 MB/sec Timing buffered disk reads: 168 MB in 3.01

Updating VMware Server Serial Number

How to update a linux VMware servers serial number from a windows VMware console. Get the serial number from http://www.vmware.com Open up the VMware Server Console on the windows machine and login to the linux server as root. Click on Help -> Enter Serial Number Enter

Setting up VMware Server on Linux

Instructions on how to setup VMware server on linux and access it from a windows machine. Pre-SetupDownload VMware server rpm for Linux from http://www.vmware.com and register for a free serial number. The current version is 1.0.3. Setup access to the server. See Installing Cygwin for

Creating a new linux file system

Creating a ext3 file system on a new USB disk. Partition Table# /sbin/fdisk /dev/sdc The number of cylinders for this disk is set to 60801. There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with: 1. software that

Copying directories between file systems

Copying files from one directory to another using find and cpio. cd /old_file_system/ find . -print -depth | cpio -pamVd /new_file_system/

Link down on RedHat Linux 3

On RedHat Enterprise 3 Linux on VMWare each interface link is always down. The following needs to be added to all the ifcfg-eth in /etc/sysconfig/networking-scripts/ check_link_down() { return 1; } See http://www.vmware.com/support/guestnotes/doc/guestos_redhat90.html for more information.

No output from the Console when connecting to a Server running on Linux

The problem is that the vmx file is not executable. Go to the VM directory and run: chmod 755 *.vmx Then restart the vmware server, output will then be displayed on the console.

Syslogd Stops working after installing VMWare Server

Seems that VMWare server adds a new service to the /etc/service file. If you have SELinux running the file's security context changes. To fix run: /sbin/restorecon /etc/services For more information see http://www.vmware.com/community/thread.jspa?messageID=435464

Mounting ISO in Linux

To mount an ISO file in linux so it turns up as a directory structure do the following: mount -o loop -t iso9660 filename.iso /mnt/iso Simple as that.

Installing Java on Fedora Core 3 using JDK 1.4.2

Excellent Howto for setting up Tomcat5 from jpackage.org on RedHat Fedora Core3. http://www.mksearch.mkdoc.org/howto/jpackage-sun-fc3/ But required JDK 1.4.2 to be used in place of 1.5 Downloaded http://mirrors.sunsite.dk/jpackage/1.6/generic/non-free/SRPMS/java-1.4.2-sun-1.4.2.

Setting up sshd for Public Key Authentication

To create key only authentication the users public key needs to be put on the server in their home directory under .ssh/authorizated_keys. Create the users private key on their workstation: ssh-keygen -t rsa Send the private key to the server: cat .ssh/id_rsa.pub | ssh newmachine "

Cyrus Imapd 2.2.12 and Autocreate Patch

Building cyrus-imapd 2.2.12 with the autocreate patch causes an error when compiling. To fix edit the imap/Makefile and add the following to the end of the CPPFLAGS parameter -I../et Then resume the make.