Setting up disk space utilization alerts in Google Stackdriver is almost unbelievably tricky. It’s easy to think that you can just choose the metric “Disk Utilization” and add a condition to alert when disk utilization crosses some threshold for some length of time (such as over 55% for 1 hour). File System Type Filter Your […]
Disk space utilization monitoring in Google StackDriver Read More »
I love using Salt to configure and manage servers at scale. Typically, a Salt master server manages an army of servers which are on the same private network. A salt-minion daemon runs on each client server and communicates with the master. Sometimes you need to manage a server which is outside of your internal network,
Managing remote servers with salt-ssh Read More »
Scenario A single Percona MySQL 5.7 server replicates asynchronously with a cluster of Percona MySQL 5.7 servers. After rebooting the single server, replication failed with the following symptoms: mysql> show slave status \G**************************** 1. row ************** Slave_IO_State: Waiting to reconnect after a failed registration on master Master_Host: my-replication-partner Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File:
MySQL replication fails with WSREP error after restart Read More »
Overview of the Netgear GS Switch Series Netgear switch models GS728TS, GS728TPS, GS752TS, and GS752TPS (Gigabit Smart Switches) are value-priced edge switches (about $1000 on Amazon for the GS752TPS 48-port model with PoE) with limited Layer 3 routing capabilities. These switches are best deployed as edge switches in a small office environment with a limited
Netgear GS728TS, GS728TPS, GS752TS, and GS752TPS Switch Configuration Guide Read More »
Creating Kubernetes secrets isn’t intuitive the first time you do it. A common reason to use a secret is to add a SSL/TLS certificate to a cluster. Kubernetes provides two ways to add a secret: directly on the command line, and from a YAML source file. First, let’s generate a test certificate to work with
Creating Kubernetes Secrets Using TLS/SSL as an Example Read More »
I found the solution for getting the New Relic APM Agent to run on a CentOS 7 system with SELinux Enforcing. The only SELinux modification you have to make is to change the context of the log file directory /var/log/newrelic. You can temporarily make these changes with the chcon command: Kill any running instances of
New Relic APM on Fedora/CentOS/RedHat with SELinux Enforcing: Solved Read More »
I’m moving to a new address in Central Florida which has multiple Internet Service Providers (ISPs) available. Spectrum (formerly BrightHouse) provides speeds up to 100Mbps via cable modem. AT&T just installed fiber in the neighborhood, so I was excited to find out what they would offer. Spectrum Cable Internet Here’s a cost breakdown by service:
Internet Service Comparison: Spectrum Cable Modem vs AT&T Fiber Read More »
Kickstart is a type of file that’s used to automatically install RedHat or CentOS Linux on a physical or virtual server. If you are managing more than a few servers, it’s a good idea to configure the servers via kickstart files instead of logging in and configuring each one manually. However, some unfortunate choices were
Configure CentOS/RedHat VMs with Kickstart files on Virtualbox Read More »
“Cross-Site Request Forgery (CSRF) is an attack that forces an end user to execute unwanted actions on a web application in which they’re currently authenticated” (OWASP definition) CSRF is related to Cross-Site Scripting (XSS), but does not require the execution of Javascript or any other front-end code. In fact, APIs are increasingly vulnerable to CSRF
Protecting a RESTful JSON API from a CSRF attack Read More »
On October 15, 2017, security researcher Mathy Vanhoef announced the discovery of KrackAttacks, a serious flaw in the WPA2 encryption protocol that encrypts most WiFi connections. Using this method, an attacker can decrypt traffic from almost any wireless access point (WAP) and clients. Every WiFi access point will need to be upgraded with patch that prevents
Upgrade Ubiquiti UniFi Access Points (WAP) now to avoid KrackAttack Read More »