RHEL7

How to fix Meltdown & Spectre Vulnerabilities on Redhat Linux?

meltdown-spectre - Redhat

Redhat is closely working with Intel and AMD to mitigate the risk of micro-architectural (hardware) implementation issues which are named as Meltdown and Spectre. These vulnerabilities are mostly affecting many modern microprocessors which include Intel, AMD, IBM power and ARM processors. These issues can be overcome by updating Linux kernel, virtualization-related components, and/or in combination with a microcode update (Firmware). To …

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LINUX – SCSI Device Management – Identifying Devices

Linux SCSI Devices Management

This article is going to share very least used SCSI commands on Linux operating systems. These commands will be very useful to identifying SCSI devices and tuneable parameters. There are few utilities which can be used to get the detailed information about the scsi devices. lsscsi is most command tool which scans sysfs pseudo file system to provide the required …

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Let’s Start exploring the Docker – Container World

hypervisor - Vmware vs Docker

Virtualization industry is bringing up many interesting and yet useful products in the market to reduce the IT cost.  VMware revolution demonstrated that how to utilize  the hardware effectively using hypervisor and other sibling products.  Similarly openstack development also going on aggressive pace to reduce the virtualization product cost by utilizing  opensource technologies. Docker was no where in the competition but …

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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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