It may be hard to imagine on the development side, but there are instances where a deployed host is not accessible from the Salt Master in a production environment. This forces a bit of creativity if you have a set of standard formulas you need to apply to the host. For instance, imagine a host … SaltStack: Running a masterless minion on Ubuntu
For full instructions on installing the AppDynamics Controller on Linux, see the official documentation. However, when you get to the step for installing in silent mode, it can be confusing because although it shows you how to specify the path to a response file and the keys available, it does not give you a sample … AppDynamics: Silent Install of Controller on Ubuntu and license directory
The Dirty COW vulnerability affects the kernel of most base Ubuntu versions. Especially when running an Ubutu HWE stack, it can be a bit confusing to determine if your kernel and Ubuntu version are affected. If you need to validate patching, then you can use a simple C program to exercise this read-only write vulnerability … Ubuntu: Determine system vulnerability for Dirty COW CVE-2016-5195
When automating software and infrastructure, it is not uncommon to need to supply a user id and password for installation or other operations. While it is certainly possible to pass these plaintext credentials directly in the state, this is not best practice. # not best practice!!! testdb_user: mysql_user.present: – name: frank – password: “test3rdb” – … SaltStack: Keeping Salt Pillar data encrypted using GPG
The prevalence of the long chains of firewall and reverse proxy solutions present in production infrastructure (and made even more popular with the dynamic routing introduced with containers) has made analysis of the end-user side of the network exchange a critical tool in troubleshooting. Fiddler has long been a solid tool for both proxy capture … Ubuntu: Using Fiddler to analyze Chrome/Firefox network capture
If you installed (or upgraded to) a later Ubuntu point release: >= 12.04.2, >=14.04.2, or >=16.04.2, you may now be wondering why the system is warning you upon every login that you will no longer receive security updates. WARNING: Security updates for your current Hardware Enablement Stack ended on 2016-08-04: * http://wiki.ubuntu.com/1404_HWE_EOL Although the first … Ubuntu: HWE Hardware Enablement Stacks, LTS, and the Kernel
When tasked with deploying a web application and it is not responsive to your browser requests, sometimes you need to take a step back from the complexity of your full stack and run a quick sanity check. You can use netcat as a simple web server to prove to yourself that the network infrastructure is … Ubuntu: Simulating a Web Server using Netcat
Although virtualization has pushed a self-service culture for infrastructure, it is still common in production environments to need your Network Operations team to open the required ports necessary for any new application deployment. So, while you may be able to create the base virtualized host, you can’t go much further without the network connectivity. And … Ubuntu: Pre-Validate Network ACL and Firewall Connectivity with Netcat
When troubleshooting basic connectivity from your SaltStack minions to your Salt master, the first thing to remember is the basic flow – the minions initiate the connection to port 4505/4506 on the Salt master. With this in mind, if you have modified /etc/salt/minion so that the master is explicitly set and logs are set to … SaltStack: Troubleshooting Basic Network Connectivity of Minion on Ubuntu
If your Ubuntu host is authenticating against an Active Directory Domain Controller, you may find there are multiple subdomains or transitive trusts visible. Which is not a problem in most cases – but if your host is in a subnet where a connection to these other subdomain or transitive trust domains is not possible, you … Ubuntu: Ignoring Transitive Trust Domains when using Samba/Winbind
Flashing the firmware of the Linksys WRT1X00AC/S is well documented on the OpenWrt wiki. So I don’t feel the need to go over the architectural concepts in this article, but I did want to provide instructions for the Ubuntu specific tools you can use to flash the firmware. If you want to try flashing to … OpenWrt: Flashing Linksys WRT1X00AC/S from USB-TTL Using Ubuntu
There are four main repositories for Ubuntu: Main, Universe, Restricted, and Multiverse. The Ubuntu CD contains the packages from the Main and Restricted repositories, so even if you do not have an Internet connections those will be available. However, if you have booted from the LiveCD, and did not initially configure a wired or wireless … Ubuntu: Enabling the Ubuntu universe Repository
The Trivial File Transfer Protocol (TFTP) is an extremely simple protocol most often used for network booting strategies, such as PXE and flashing OpenWrt images unto consumer routers. I go over full instructions for flashing OpenWrt using Ubuntu and flashing a sysupgrade in another post, this article will focus specifically on setting up a tftp … OpenWrt: Installing a TFTP Server on Ubuntu for OpenWrt Firmware Updates
If you experience hanging when installing the gutenprint drivers for a network printer from the desktop, try manually installing the gutenprint drivers from the console first. Most likely, you will see a screen like below, and the progress bar will continually cycle but never end. If you can’t cancel, you can use the ‘xkill’ command … Ubuntu: Hang While Installing gutenprint as Network Driver
In production data centers, it is not uncommon to have limited public internet access due to security policies. So while running ‘apt-get’ or adding a repository to sources.list is easy in your development lab, you have to figure out an alternative installation strategy because you need a process that looks the same across both development … Ubuntu: Installing Packages without Public Internet Access
Update Feb 2021: See my newer article on extending an LVM volume group on Ubuntu Focal using either the same physical disk or a new disk using parted. It is common for a virtualized Guest OS base image to have a generic minimal storage capacity. But this capacity can easily be exceeded by production … Ubuntu: Extending a virtualized disk when using LVM
We live in a multi-platform world, and the ability to easily share folders of content between users in the same protected network is a function made very convenient in the Windows world with CIFS shares (e.g. \\mydesktop\sharedfolder). Luckily for Ubuntu users, it is pretty easy to setup CIFS shares to offer that same interoperability with … Ubuntu: Creating a Samba/CIFS share to quickly share files with Windows
Whether you are updating the official LinkSys router firmware or taking it a step further and installing open-source firware like OpenWrt, serial level access to your Linksys router is the most dependable way of guaranteeing a connection. And if you have tried to flash the firmware via the web admin interface and after a reboot … Ubuntu: Serial level access to your Linksys WRT1X00AC/S
It is common for a virtualized Guest OS base image to have a generic minimal storage capacity. But this capacity can easily be exceeded by production scenarios, performance testing, logging, or even the general cruft of running a machine 24×7. For this reason, extending a virtualized disk can be extremely helpful. Here is a walk … Ubuntu: Extending a virtualized disk using fdisk when not using LVM
Before virtualization, there was a stronger argument for using a swap partition instead of a swap file for servers. A fragmented swap file could lead to performance issues that a statically sized and placed partition did not have consider. But once virtualization comes into play, unless you go to great lengths to segment your storage … Ubuntu: Using a swap file instead of swap partition for virtualized server VMs
There are many consumer side printers that provide the ability to scan a document to PDF. But unless you have a high-end series, the printer may only be capable of scanning one side at a time, which means you end up with a “front.pdf” and “back.pdf”. If you have a Linux desktop or laptop, luckily … Ubuntu: Using pdftk to stitch together two-sided PDF
It is time consuming to restart the entire Logstash service and refeed it input when working on a grokparsefailure. Here is an easy way to test a line of input or log file against a grok pattern:
Updated Feb 2019 based on Spotify updates that broke this functionality. If the keyboard media keys do not work from your Ubuntu desktop, you can use D-Bus support to send the proper commands to Spotify. Validate the following commands from the console: