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CentOS High Availability

By : Resman

4.5 (12)

CentOS High Availability

4.5 (12)

By: Resman

Overview of this book

This book is targeted at system engineers and system administrators who want to upgrade their knowledge and skills in high availability and want to learn practically how to achieve high availability with CentOS Linux. You are expected to have good CentOS Linux knowledge and basic networking experience.

Preface

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Free Chapter

1. Getting Started with High Availability

1. Getting Started with High Availability

What is high availability?

System design

Computer clusters

High-availability solutions

Summary

2. Meet the Cluster Stack on CentOS

2. Meet the Cluster Stack on CentOS

Cluster stack software

The cluster communication layer

The cluster resource management layer

A theoretical cluster service example

Cluster stack on CentOS Linux

Preparing for cluster stack software installation

Summary

3. Cluster Stack Software on CentOS 6

3. Cluster Stack Software on CentOS 6

Cluster infrastructure

Cluster operating system preparation

Installing and configuring Corosync

Installing and configuring CMAN

Summary

4. Resource Manager on CentOS 6

4. Resource Manager on CentOS 6

Working with RGManager

Configuring failover domains

Adding cluster resources and services

Managing cluster services

Removing cluster resources and services

Summary

5. Playing with Cluster Nodes on CentOS 6

5. Playing with Cluster Nodes on CentOS 6

Adding a new cluster node

Removing a cluster node

Summary

6. Fencing on CentOS 6

6. Fencing on CentOS 6

Fencing

Fencing configuration

IPMI management board fencing

HP iLO management board fencing

Fencing test

Summary

7. Testing Failover on CentOS 6

7. Testing Failover on CentOS 6

Hardware failure

Network failure

Summary

8. Two-node Cluster Considerations on CentOS 6

8. Two-node Cluster Considerations on CentOS 6

Quorum in a two-node cluster

Two-node cluster configuration

Quorum disk

Summary

9. Cluster Stack Software on CentOS 7

9. Cluster Stack Software on CentOS 7

Cluster infrastructure

Installing and configuring Corosync

Summary

10. Resource Manager on CentOS 7

10. Resource Manager on CentOS 7

Working with pcs

Adding cluster resources, constraints, and resource groups

Managing resources

Removing cluster constraints, resource groups, and resources

Summary

11. Playing with Cluster Nodes on CentOS 7

11. Playing with Cluster Nodes on CentOS 7

Adding a new cluster node

Cluster node standby mode

Removing a cluster node

Summary

12. STONITH on CentOS 7

12. STONITH on CentOS 7

Fencing

Configuring fence devices

IPMI management board fencing

HP iLO management board fencing

Fence test

Summary

13. Testing Failover on CentOS 7

13. Testing Failover on CentOS 7

Hardware failure

Network failure

Summary

14. Two-node Cluster Considerations on CentOS 7

14. Two-node Cluster Considerations on CentOS 7

Quorum in a two-node cluster

Two-node cluster configuration

Summary

Index

Index

Network failure

In the following example, you will perform a cluster node network failure test. Network failure can occur due to network infrastructure equipment failure or cluster node network card failure. An important part of this test is the fact that the problematic cluster node with the network failure could still be online and could still have access to the shared cluster storage and cluster data. It is very important for the fencing mechanism to fence the problematic cluster node and make sure it is offline, without access to the cluster data.

The cluster from the following example is configured to provide a webserver cluster service. The webserver cluster service is a combination of a cluster IP address and an Apache webserver instance. The webserver cluster service is running on the node-3 cluster node. In the following screenshot, you can see the cluster status prior to the network failure test:

Network failure

You can proceed to simulate the node-3 cluster node's network failure by removing...

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Tech Concepts

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Programming languages

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