Slice Administration

Latest Article:

STL to ORD Migration Best Practices

Customers with slices in our St. Louis datacenters (STL-A and STL-B) will be migrated to our Chicago datacenter (ORD) as part of the transition from Slicehost to Rackspace Cloud. Customers will be notified in advance of the slice migration, giving them time to optimize their slices for the move.

Basic administration is a skill that should be mastered if you are to have a happy Slice.

As with all aspects of administering a server, try to learn the basics before using web based applications - there may come the day when the web server is not working.

Slice Admin:

Memory Management with Free: Monitoring of memory gives an easy and instant overview of the state of your Slice. Use 'free' to give you basic details of RAM usage.

System monitoring with top: Using top gives a real-time overview of system processes and shows precisely what is using system resources.

Solve Slice or Website 'Down' Issues Quickly: When your website is down or your slice is unreachable, you can run through a handful of routine tests to identify which of the most common causes could lie behind the problem.


Using iotop to check I/O and swap: The iotop utility provides an easy-to-use interface for monitoring swap and disk I/O on a per-process basis.


Using dstat to check I/O and swap: For a flexible reporting tool that can yield information ranging from CPU use to the top I/O-consuming process look no further than dstat.

Using dstat with scripts and external modules: Here we look at the basic scripting options for dstat as well as an overview of its external modules.


Log rotation:

Understanding logrotate: It's no fun when log files grow out of control. In this two-part series, learn how to use logrotate to keep those logs in check.


Linux file permissions:

Linux file permission concepts: Linux file permissions are strange and wondrous things. Start down the path of understanding by looking at the core concepts behind them before moving on to practical applications.

Checking Linux file permissions with ls: Once you understand Linux file permissions, the next step on the road to enlightenment is learning how to check the permissions for a file or directory.

Using chmod, part 1 - symbolic mode: We've done the thinking and the seeing, now to start the doing. Continuing our series on file permissions, we look at using the chmod command.

Using chmod, part 2 - octal mode: Now we look at the other way chmod can be used - with numbers. This is the more commonly-used format, but also the least user-friendly.

Umask and unusual file permissions and types: In this last entry in our series on Linux file permissions we look at the umask and some more advanced file permissions. We also throw in some discussion of other file types you may see in a directory listing.


Cron and task scheduling:

Basic Linux task scheduling with cron: Sometimes you want to run commands nightly or weekly. You could just log in and run them yourself, but scheduling those tasks with cron is less hassle in the long run.

Fine-grained task scheduling with cron.d: If you need more control over scheduling jobs than using the standard intervals like hourly and monthly, you can put a file in cron.d and tell it exactly how often to run.

Multi-user task scheduling with crontab: The crontab works much like cron.d, just with its own command for access and more flexibility when you want multiple users setting their own schedules.


Monitoring servers:

Using ServerDensity to monitor a slice: You have a number of options for monitoring your slice. Commercial services like ServerDensity can be easier to set up and maintain than free monitoring applications.


Installing munin overview: Anticipating problems and resource shortages on a slice can be more valuable than fixing them after they've happened. A monitoring tool like munin lets you watch your slice's resource use over time. The graphs will highlight issues before they cause downtime or bandwidth quota overages.

Installing additional munin nodes overview: Following up on the article about installing a munin master slice, if you want to monitor additional slices you'll need to install a munin node service on each.

Enabling munin node plug-ins overview: Munin uses plug-ins to determine what data is gathered and reported. It includes several plug-ins for the types of data most people would be interested in, but not all of those plug-ins are enabled on a fresh installation.


Capturing packets with tcpdump: Tcpdump is a powerful network debugging tool which can be used for intercepting and displaying packets on a network interface.


Resize and backup optimization:

Speed up resizes - Part 1: This guide will help you shorten slice resize times, slice moves, and slice backup times.

Speed up resizes - Part 2: In this second part we examine another use case and look at the resize process in general.


Recovery:

How to use Rescue Mode: Rescue Mode grants you full access to a non-bootable slice's filesystem. You can use it to modify problem configuration files or to use scp to copy data from the slice to a remote location.


SFTP:

Secure FTP Transfers: Using FTP to transfer files to and from your Slice can cause issues with security - let's look at SFTP as a safe and secure method.


DNS Records

Introduction to dig: Creating new DNS records is one thing, but what if you want to check them before they are fully propagated?

Verifying DNS configurations: If you've gone through our e-book on configuring DNS this article helps you verify your settings.

Using dig with external nameservers: Checking your DNS on external servers after your changes have propagated.

Getting more out of dig: Looking at other information dig can return about a domain.


Network Time Protocol

Using NTP to sync time: Keeping your system's date and time accurate is easy to do using NTP.


iptables

Introducing iptables part 1: This article provides an overview of how to understand the Linux kernel firewall for ipv4 using iptables and the Filter table. It is intended for beginners to intermediate linux users and provides an insight on basic configuration concepts.

Introducing iptables part 2: This article continues our introduction to iptables, focusing on syntax, adding and deleting rules.

Introducing iptables part 3: The third part of our introduction to iptables wraps things up by looking at launch at startup configurations and useful examples.


Linux Server Migration:

Migrating a Linux server from the command line - preparing the servers: Sometimes you need to move everything from one server to another. It can take a while for all those files to transfer, but in this article we try to make the rest of the process as painless as possible.

Migrating a Linux server from the command line - running the sync: With our preparations done it's time to start copying files between your Linux servers.

Linux migration tips and tricks: In this article we give some advice on how to make your Linux server migration safer and discuss migrating on a per-package basis.


The Kernel

Downloading and using kernel source code (2.6.32.12 and newer) overview: If you know you need to get your kernel source (or at least its headers) for a kernel version 2.6.32.12 and newer, you can find instructions to do so here.


Using pv-grub to run custom kernels overview: The pv-grub kernel option allows your slice to boot from your own kernel instead of one of ours.

Please feel free to request articles or comment with any suggestions or ideas of your own.

PickledOnion