Redhat-LINUX

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 …

Read More »

Meltdown and Spectre Vulnerabilities – Big Threats

meltdown-spectre

Meltdown and Spectre Vulnerabilities have made 80% of servers as Vulnerable in overnight, thanks to  Google Project Zero team and other security researchers who have brought such a worst vulnerabilities to the world (At least now). Meltdown vulnerability basically melts security boundaries which are normally enforced by the hardware (CPU).  Spectre name is based on the root cause, “speculative execution”. Spectre is harder to exploit …

Read More »

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 …

Read More »

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 …

Read More »

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” …

Read More »

RHEL 7 – Pacemaker – Cluster Resources/Group Management – Part 6

RHEL 7 cluster Resource group

In Pacemaker/Corosync  cluster (RHEL 7 HA),  resources management and resource group management are important tasks . Depends on the cluster HA services, you might need to configure N-number of resources. In most of the cases , you might need to start set of resources sequentially, and stop in the reverse order.  To simplify this configuration, Pacemaker supports the concept of groups (Resource …

Read More »

RHEL 7 – Pacemaker – Cluster Resource Agents Overview – Part 5

Pacemaker resource agents

Resource agents plays an important role in cluster management.  Resource agents are multi-threaded processes that provides the logic to manage  the resources. Pacemaker has one agent per resource type. Resource type could be a File-system , IP address , databases, virtual-domain and more. Resource agent is responsible to monitor, start , stop,validate , migrate , promote and demote  the cluster resources whenever required. …

Read More »

RHEL 7 – Configuring Pacemaker/Corosync – Redhat Cluster – Part 4

Redhat cluster - pacemaker corosync configuration

In this article, we will see that how to configure two node Redhat cluster using pacemaker & corosync on REHL 7.2. Once you have installed the necessary packages, you need to enable the cluster services at the system start-up. You must start the necessary cluster services before kicking off the cluster configuration. “hacluster” user will be created automatically during the package …

Read More »