Search icon CANCEL
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Conferences
Free Learning
Arrow right icon
Arrow up icon
GO TO TOP
Red Hat Enterprise Linux Troubleshooting Guide

You're reading from   Red Hat Enterprise Linux Troubleshooting Guide Identify, capture and resolve common issues faced by Red Hat Enterprise Linux administrators using best practices and advanced troubleshooting techniques

Arrow left icon
Product type Paperback
Published in Oct 2015
Publisher
ISBN-13 9781785283550
Length 458 pages
Edition 1st Edition
Tools
Concepts
Arrow right icon
Author (1):
Arrow left icon
Benjamin Cane Benjamin Cane
Author Profile Icon Benjamin Cane
Benjamin Cane
Arrow right icon
View More author details
Toc

Table of Contents (14) Chapters Close

Preface 1. Troubleshooting Best Practices FREE CHAPTER 2. Troubleshooting Commands and Sources of Useful Information 3. Troubleshooting a Web Application 4. Troubleshooting Performance Issues 5. Network Troubleshooting 6. Diagnosing and Correcting Firewall Issues 7. Filesystem Errors and Recovery 8. Hardware Troubleshooting 9. Using System Tools to Troubleshoot Applications 10. Understanding Linux User and Kernel Limits 11. Recovering from Common Failures 12. Root Cause Analysis of an Unexpected Reboot Index

Changing user limits


Since we suspect the open files limit is preventing the application from executing, we can set its limit to a higher value. However, this is not as simple as executing ulimit –n; the following output is what we get when it's executed:

$ ulimit -n
1024
$ ulimit -n 5000
-bash: ulimit: open files: cannot modify limit: Operation not permitted
$ ulimit -n 4096
$ ulimit -n
4096

By default, on our example system the highest the vagrant user is allowed to raise the open files limitation to is 4096. As we can see from the preceding error, anything higher is denied; but like most things with Linux we can change this.

The limits.conf file

The user limits that we have been using and modifying are part of Linux's PAM system. PAM or Pluggable Authentication Modules is a system that provides a modular authentication system.

For example, if our system was to utilize LDAP for authentication, the pam_ldap.so library would be used to provide this functionality. However, since our system uses...

lock icon The rest of the chapter is locked
Register for a free Packt account to unlock a world of extra content!
A free Packt account unlocks extra newsletters, articles, discounted offers, and much more. Start advancing your knowledge today.
Unlock this book and the full library FREE for 7 days
Get unlimited access to 7000+ expert-authored eBooks and videos courses covering every tech area you can think of
Renews at €18.99/month. Cancel anytime