Recent Posts

Puppet – How to install and configure Puppet Agent (Client) ?

Login Page - Puppet

Once you have configured the Puppet Server, you can start adding the puppet agents to it. This article will brief about installing and configuring the puppet agent on Linux systems (RHEL 7 and Ubuntu 14.04).  Puppet agents are nothing but the client machines which will regularly pulls configuration catalogs from a Puppet master and applies them to the local system. Puppet …

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Puppet – How to install and configure Puppet Enterprise (Master) ?

This article is going to brief about the Puppet Server – Enterprise installation and configuration. We are going to install the puppet server  in monolithic mode. In monolithic installation, Puppet Master , Puppet console , Puppet DB will be installing on one node. This is the simple method to evaluate puppet enterprise and you can manage up to 500 puppet agent nodes. To know more about …

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Puppet – Configuration Management Software – Overview

Large Split Installation

Puppet  is an open-source configuration management / IT automation software that allows system administrators to programmatically provision, configure, and manage servers, network devices, and storage, in a datacenter or in the cloud. Puppet is written on RUBY language and it is produced by Puppet Labs.  Configuration Management tools uses either push or pull methods. Puppet uses pull method. In this method, puppet agents …

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RHEL7 – Configuring GFS2 on Pacemaker/Corosync Cluster

GFS2 - RHEL 7

This article will briefly explains about configuring the GFS2 filesystem between two cluster nodes. As you know that GFS2 is cluster filesystem and it can be mounted on more than one server at a time . Since multiple servers can mount the same filesystem, it uses the DLM (Dynamic Lock Manager) to prevent the data corruption. GFS2 requires a cluster suite …

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RHEL 7 – How to configure the Fencing on Pacemaker ?

RHEL 7 STONITH

Fencing (STONITH) is an important mechanism in cluster to avoid the data corruption on shared storage. It also helps to bring the cluster into the known state when there is a split brain occurs between the nodes. Cluster nodes talks to each other over communication channels, which are typically standard network connections, such as Ethernet. Each resources and nodes have “state” …

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RHEL 7 – Pacemaker – Configure Redundant Corosync Links on Fly– Part 10

Corosync Links - RHEL7

Corosync cluster engine provides the reliable inter-cluster communications between the cluster nodes. It syncs the cluster configuration across the cluster nodes all the time. It also maintains the cluster membership and notifies when quorum is achieved or lost. It provides the messaging layer inside the cluster to manage the system and resource availability. In Veritas cluster , this functionality has been provided by LLT + …

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RHEL 7 – Pacemaker – Define the Resource Behaviour – Part 9

Pacemaker resource agents

In Pacemaker/Corosync cluster, there are may aspects/key elements that we need to understand before playing with cluster operations. Otherwise , it might cause unnecessary outage/downtime for the services. The most important elements are setting the preferred resource location , ordering (defining dependencies) , resource fail counts, resource-stickiness, colocation, clone, master/slave, promote/demote etc. Let’s go through the article and understand how these elements contributes …

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RHEL 7 – Pacemaker – Cluster Node Management – Part 8

Redhat Cluster with Pacemaker

This article will demonstrates about the Pacemaker/Corosync cluster membership, node management and other  cluster operational tasks. Periodically , you might need to take the cluster node offline to perform the maintenance activities like OS package update/upgrade , hardware replacement/upgrade etc. In  such cases ,you need to put the cluster node in to standby mode to keep the cluster operational on other node …

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RHEL 7 – Pacemaker – Configuring HA KVM guest – Part 7

HA KVM guest using Pacemaker

If you have followed the KVM article series in UnixArena , you might have read the article which talks about the KVM guest live migration. KVM supports the Guest Live migration (similar to VMware vMotion) but to provide high availability , you need need a cluster setup . (Like VMware HA).  In this article ,we will configure the KVM guest …

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