Rails Devops Cheatsheet

A collection of command line tips and time-saving snippets curated by Rubytune

Not all snippets work on all distros! Boo! Make sure you know what you are doing! You might have to apt-get/homebrew/etc. Corrections and tip-offs to sudara@rubytune.com Download the PDF Copy

Process Basics

All processes, with params + hierarchy Show all ruby-related PIDs and processes What is a process doing? What files does a process have open? (also nice to detect ruby version of a process) Flavors of kill Keep an eye on a process

Memory

How much mem is free? Learn how to read output Are we swapping? First line is avg since boot List the top 10 memory hogs Detect OOM and other bad things Disable OOM killer for a process /proc/$PID/oom_adj"/>

Disk/Files

Check reads/writes per disk Files (often logs) marked for deletion but not yet deleted Overview of all disks Usage of this dir and all subdirs Find files over 100MB Low hanging fruit for free space. Check /var/log too! Find files created within the last 7 days Find files older than 14 days Delete files older than 14 days Monitor a log file for an IP or anything else Generate a large file (count * bs = total bytes)

Network

TCP sockets in use Get IP/Ethernet info host <‖> IP resolution Curl, display headers (I), follow redirects (L) Traceroute with stats over time (top for traceroute) Requires install Traceroute using TCP to avoid ICMP blockage List any IP blocks/rules Drop any network requests from IP Show traffic by port Show all ports listening with process PID D/L speed test (don't run in prod! :)

Terminal & Screen

Start a screen session as the current user Join/re-attach to a screen session Record a terminal session filename.timing"/> Playback a recorded terminal session

Tips n Tricks

Run Previous command as root Change to last working dir Run something forever

Databases

"Tail" all queries hitting mysql. Learn more Connect to production mysql locally on port 3307 via ssh Learn More