Troubleshooting Ubuntu Server

Table of Contents

Troubleshooting Ubuntu Server

Credits

About the Author

About the Reviewer

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Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Errata

Piracy

Questions

1. Package Management

Getting started with packages

Package

Repository

The .deb packages

Dependency

Open source

Using dpkg for package management

Understanding the apt-get package management tool

Updating the repository list with the apt-get update command

Installing a package with the apt-get install command

Upgrading a package with the apt-get upgrade command

Cleaning with the apt-get clean command

Purging a package with the apt-get purge command

Fixing unsuccessful installations with the apt-get –f command

Checking for broken dependencies with the apt-get check command

The apt-cache tool

Searching for a package with the apt-cache search command

Package management with aptitude

Configuration and extra repositories

Resolving the failed to get error

Downloading software from an outside repository

Automatic updates

Security updates

Kernel updates

Application updates

The unattended-upgrades package

Creating a repository mirror

Setting up a mirror machine

Configuring the /etc/apt/mirror.list file

Using the local mirror

Summary

2. Networking and DNS

Networking concepts

IP addressing

DHCP client for dynamic addresses

Assigning a static IP address

DHCP

Installation

Configuration

Network sniffing with tcpdump

Capturing packets from eth0

Saving the tcpdump results in a file

Reading packets saved in a file by tcpdump

Readable timestamps in packets

Reading packets of a specific protocol

Reading packets on a specific port

Reading TCP packets between two hosts

Binding and bonding

Binding

Bonding

DNS

Setting up DNS

Setting up primary and secondary DNS servers

The hints file – zone .

The local host file – zone 0.0.127.in-addr.arpa

The reverse zone file – zone 24.126.10.in-addr.arpa

The primary zone file – zone ubuntuserver.org

The primary zone file

The reverse zone file

PTR records

Summary

3. Network Authentication

OpenLDAP

Installation

Populating the database

Logging

Access control

Kerberos

Installation

Database setup

Setting up the Kerberos client

Kerberos SSH and logon

Integrating LDAP with Kerberos

Installation

Database setup

OpenSSH, public, and private keys – passwordless SSH

The SSH client and the server

Setting up passwordless SSH

Disabling password authentication

Allowing or denying users to SSH

Greeting users with a banner

Summary

4. Monitoring and Optimization

Nagios

The Nagios setup

Adding another host in Nagios

Nagios templates

Nagios hostgroups and services

Nagios setup alerts

Writing a Nagios plugin

The NRPE plugin

Enabling external commands

Puppet

Installing Puppet

Setting up the client

Setting up the manifest

ClusterSSH

Summary

5. Process Management

The basics of process management

$$ and $PPID

pidof

Parent and child

fork() and exec()

exec

ps

pstree

ps fx

ps -C and pgrep

top

Signaling processes

kill

Listing all signals

kill -1 or SIGHUP

kill -15 or SIGTERM

kill -9 or SIGKILL

SIGSTOP and SIGCONT

pkill

killall

Process priorities

renice

nice

Background processes

jobs

& (ampersand)

jobs -p

Suspended state with Ctrl + Z

bg

fg

Summary

6. Shell Management, Tools, and User Management

The Secure Shell server

Installing the SSH server

Configuration

Default settings for the SSH server

The SSH configuration file

Using passphrases

Scheduling jobs with cron

Scheduling user cron jobs

Configuring jobs using at

Job schedule security

Optimizing the shell

Bash profiles

The /etc/bash.bashrc file

The /etc/profile file

Variables in bash

User management and file permissions

User management in Ubuntu

Adding and removing users

Managing file permissions

Understanding file permissions

Changing permissions with chmod

Modifying ownership using chown and chgrp

Setting default permissions with umask

Special file permissions

Summary

7. Virtualization

What is virtualization?

libvirt

Installation

virt-install

virt-clone

Managing the virtual machine

virsh

The virtual machine manager

The virtual machine viewer

JeOS and vmbuilder

JeOS

vmbuilder

Setup

Adding users to groups

Installing vmbuilder

Defining the virtual machine

JeOS installation

IP address

Enabling the bridge

Partitions

Setting the user and password

Final steps in the installation

First boot

First login

Auto updates

ACPI handling

The complete command

Summary

8. OpenStack with Ubuntu

The OpenStack architecture

The environment

Security

Networking

OpenStack networking

The controller node

The network node

The compute node

Verifying the network connectivity

Network Time Protocol

Configuring the controller node

Installing the NTP service

Configuring the NTP service

Configuring other nodes

Installing the NTP service

Configuring the NTP service

OpenStack packages

Enabling the OpenStack repository

Finalizing the installation

Database

Installing and configuring the database server

Finalizing the installation

The messaging server

Installing the RabbitMQ message broker service

Configuring the message broker service

The Identity service

Installing and configuring the Identity service

Configuring the prerequisites

Installing and configuring the components

Finalizing the installation

Tenants, users, and roles

Configuring prerequisites

Creating tenants, users, and roles

The service entity and API endpoint

Configuring the prerequisites

Creating the service entity and API endpoint

The Image service

Installing and configuring the Image service

Configuring the prerequisites

Installing and configuring the Image service components

Finalizing the installation

The Compute service

Installing and configuring the Compute service

Configuring the prerequisites

Installing and configuring the Compute service components

Finalizing the installation

Installing and configuring the compute node

Installing and configuring the compute hypervisor components

Finalizing the installation

OpenStack networking

Installing and configuring the controller node

Configuring the prerequisites

Installing the Networking components

Configuring the server components of Networking

Configuring the Modular Layer 2 plugin

Configuring Networking on the compute node

Finalizing the installation

Installing and configuring the network node

Configuring the prerequisites

Installing the Networking components

Configuring the Networking components

Configuring the Modular Layer 2 plugin

Configuring the Layer 3 agent

Configuring the DHCP agent

Configuring the metadata agent

Configuring the OVS service

Finalizing the installation

Installing and configuring the compute node

Configuring the prerequisites

Installing the Networking components

Configuring the Networking common components

Configuring the ML2 plugin

Configuring the OVS service

Configuring Compute to use Networking

Finalizing the installation

Creating initial networks

External networks

Creating an external network

Creating the subnet for the external network

The tenant network

Creating a tenant network

Creating the subnet for the tenant network

Creating the router to attach the external and tenant networks

Dashboard

Prerequisites

Installing and configuring the dashboard

Installing the packages

Configuring the dashboard

Finalizing the installation

The Block Storage service

Installing and configuring the controller node

Configuring the prerequisites

Installing and configuring the Block Storage service components

Finalizing the installation

Installing and configuring the storage node

Configuring the prerequisites

Installing and configuring the Block Storage volume components

Finalizing the installation

The Object Storage service

Installing and configuring the controller node

Configuring the prerequisites

Installing and configuring the controller node components

Installing and configuring the storage node

Configuring the prerequisites

Installing and configuring the storage node components

Summary

9. OpenStack and Ubuntu Best Practices

Creating rings for Object Storage

Creating an account ring

Creating a container ring

Creating an object ring

Copying the configuration files for rings

Finalizing the installation

The Orchestration module

Installing and configuring

Configuring the prerequisites

Installing and configuring the Orchestration components

Finalizing the installation

The Telemetry module

Installing and configuring the controller node

Configuring the prerequisites

Installing and configuring the Telemetry components

Finalizing the installation

Installing and configuring the Compute agent

Configuring the prerequisites

Configuring the Compute agent for the Telemetry module

Finalizing the installation

Configuring the Image service

Adding the Block Storage agent for Telemetry

Configuring Object Storage for Telemetry

The Database service

Installing the Database service

Taking care of the prerequisites

Installing the Database module

The Data Processing service

Installing the Data Processing service

OpenStack flashback

Best practices for Ubuntu Server

Summary

Index

Troubleshooting Ubuntu Server

Troubleshooting Ubuntu Server

Copyright © 2015 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: September 2015

Production reference: 1180915

Published by Packt Publishing Ltd.

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Birmingham B3 2PB, UK.

ISBN 978-1-78528-414-4

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Credits

Author

Skanda Bhargav

Reviewer

Keenan Payne

Commissioning Editor

Priya Singh

Acquisition Editors

Shaon Basu

Sonali Vernekar

Content Development Editor

Gaurav Sharma

Technical Editor

Taabish Khan

Copy Editor

Roshni Banerjee

Project Coordinator

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Proofreader

Safis Editing

Indexer

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Graphics

Sheetal Aute

Production Coordinator

Nitesh Thakur

Cover Work

Nitesh Thakur

About the Author

Skanda Bhargav is an engineering graduate from Visvesvaraya Technological University (VTU), Belgaum, Karnataka, India. He did his majors in Computer Science Engineering. He is a Cloudera-certified developer in Apache Hadoop. His interests are Big Data and Hadoop. He is currently pursuing his Master's in Computer Software Engineering from San Jose State University, Silicon Valley, California.

He has been a reviewer for the following books and videos:

Building Hadoop Clusters, Sean Mikha, Packt Publishing

Hadoop Cluster Deployment, Danil Zburivsky, Packt Publishing

Instant MapReduce Patterns – Hadoop Essentials How-to, Srinath Perera, Packt Publishing

Cloudera Administration Handbook, Rohit Menon, Packt Publishing

Hadoop Map Reduce v2 Cookbook – Second Edition, Thilina Gunarathne, Packt Publishing

Data Analysis and Business Modeling with Excel 2013, David Rojas, Packt Publishing

I would like to thank my family for their immense support and faith in me throughout my learning stage. My friends have brought the confidence in me to a level that makes me bring out the best in me. I am happy that god has blessed me with such wonderful people around me, without whom this success would not have been possible.

About the Reviewer

Keenan Payne is a frontend developer for a company called Asana in San Francisco, CA. He has written for many online publications and built a CSS framework called Concise, and in his spare time, he loves to surf and make music.

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Preface

The mission of this book is to simplify the tasks of an administrator and equip them with the tools to win the battle not once, not twice, but each time the server acts in a way that is not in accordance with the usual behavior. This book will help administrators ensure that the servers do not face even a nanosecond of outage as businesses in today's world are entirely dependent on these machines.

After reading and following the guidelines carefully, you will be able to identify the problems in Ubuntu Server, diagnose the causes, and rectify them. The areas this book intends to cover are networks, CPU, memory, and handling cloud computing-related issues using OpenStack.

What this book covers

Chapter 1, Package Management, covers the different ways software can be installed, configured, upgraded, and removed using package management tools. There are various ways and tools to do this. Technical topics that are covered in this chapter are dpkg, aptitude, and apt-get, which are the command-line utilities used to automate some of the package management tasks. You will learn the various tools and methodologies to handle software, such as the command-line tools, as well as GUI for the installation, mirroring, upgrade, and removal of software along with their dependencies.

Chapter 2, Networking and DNS, deals with networking. This chapter covers how to understand, configure, and troubleshoot network-related issues. This is a very brief introduction to networking and handling wired and wireless networking. This chapter covers DNS setup, networking concepts, interface configuration, DHCP, network sniffing, binding, and bonding. Regarding DNS, the topics covered are forward zone, reverse zone, and configuring the primary master and secondary master. You will learn the networking concepts, which are key to diagnosing and rectifying networking issues in Ubuntu Server. It also covers the configuration of DHCP, DNS, and interfaces.

Chapter 3, Network Authentication, deals with network authentication for managing users' access to other systems in a secure way. It covers the different tools and methods for letting users access systems and services with restricted authentication. The technical topics covered are OpenLDAP, Kerberos, Kerberos with LDAP, NIS, Samba (optional), PAM, SSH, public and private keys, the RSA and DSA algorithms, passwordless SSH, X forwarding, and sshd. You will be able to set up and manage the users' access to systems and services as well as install, configure, and troubleshoot the services and tools.

Chapter 4, Monitoring and Optimization, deals with monitoring various resources on the server and load balancing with tools. This chapter also covers Nagios, Munin, Puppet, and ClusterSSH. System monitoring, CPU load, storage, networks, memory, resource monitoring, load balancing with IPVS, and ldirectord are also covered in this chapter. You will learn about resource monitoring for CPU, memory, and networks.

Chapter 5, Process Management, covers all the processes, their states, and how to manage them by using the command-line tools. The topics that are covered are ps, top, renice, kill, $$ and $PPID, job, fg, queues, process switching, process priority, and background jobs. You will learn how to handle process management using the command-line tools.

Chapter 6, Shell Management, Tools, and User Management, discusses shell, shell management tools, and user management. Topics such as the Secure Shell server, scheduling using cron, shell optimization, file