Found 1436 Articles for Linux

In this article we will configure and install the Graylog 1.3 (which is also referred as Graylog2) on CentOS 7, Graylog gathers the syslog’s of the machines into a centralized location. Graylog is a log management and analysis tool that can be used in many cases, for monitoring the SSH logins and unusual activity for debugging applications and logs, the uses Elasticsearch, Java and MangoDB.Graylog Features and ComponentsGrayLog Server Node − Server mainly receives and processes the messages and communicates with the non-servers components.Elastic search Nodes − This will store the messages and logs.MangoDB − This stores metadata.Web Interfaces − ... Read More

In this article, we will learn how to configure and install the Dropbox client and run as a service on CentOS7 server. This makes the server to connect with Dropbox and keep a copy of files synchronized. To complete the setup we needed a non-root user with Sudo permissions or a root user.Installing the Dropbox ClientWe can download the latest Linux Dropbox client from the below link.# cd ~ # curl -Lo dropbox-linux-x86_64.tar.gz https://www.dropbox.com/download?plat=lnx.x86_64After downloading, we need to create a folder for client software and extract the compressed file which we downloaded.# mkdir -p /opt/dropbox-client # tar xzfv dropbox-linux-x86_64.tar.gz --strip ... Read More

In this article, we will learn how to install Dockers. Dockers is a very good tool which runs the application on its own containers. It works like a virtual machine which are more portable and more resource friendly and more dependent on the host OS. There are two methods of installing Docker on CentOS 7. First method is to by installation using the existing OS or spinning the server with a tool called Docker Machine and making the auto installation.Here for demo purpose, we will install on the existing OS.Installing the Docker on CentOS 7Before we begin the installation we ... Read More

In this article, we have configured Nginx which is already installed on CentOS 7 to serve the clients with gzip compression to reduce the size of the contents sent to the web site visitors. We can configure the websites to load faster which depends on the size of all the files that are downloaded by the web browser, we can do this by reducing the size of the files transmitted from the website and load faster, which also reduces the cost which we pay for the bandwidth usage. gzipis a popular data compression package, which we will configure Nginx with ... Read More

In this article, we will learn how to install Prometheus server to collect the metrics and query them and also install Grafana – a web based graphical dashboard builder. Prometheus is an open source monitoring tool with time series database. It addresses many aspects for monitoring and generating a collection of metrics and graphs for resulting the data on the dashboards along with alerting.PrerequisitesTo complete this article we needed these resources CentOS 7 installed, a user with sudo access and Dockers installed.Installing the PrometheusWe are installing the Prometheus using the Dockers, so make sure that we already installed Docker on ... Read More

In this article, we will learn about how to install and configure open source Puppet agent/master on the CentOS 7, which is from Puppet Labs. Puppet is a configuration management tool that helps system administrator to automate the configuration, provisioning and management of the server infrastructure. The Puppet agents are called as nodes and we will be using the Puppet Server packages instead of the Passenger or any other environments.We needed a root or super-users access to the servers where we want to install the Puppet master.PrerequisitesWe needed a proper DNS which is configured on the puppet server so that ... Read More

Pthreads refers to the POSIX standard (IEEE 1003.1c) defining an API for thread creation and synchronization. This defines specification for thread behavior, not an implementation. The specification can be implemented by OS designers in any way they wish. So many systems implement the Pthreads specification; most are UNIX-type systems, including Linux, Mac OS X, and Solaris. Although Windows doesn’t support Pthreads natively, some third-party implementations for Windows are available. The C program shown in Figure 4.9 demonstrates the basic Pthreads API for constructing a multithreaded program that calculates the summation of a nonnegative integer in a separate thread. Separate threads ... Read More

In Linux, when an executable stored on disk is called a program, and a program loaded into memory and running is called a process. A process is given a unique number called process ID (PID) that identifies that process to the system, when it is started. If we ever need to kill a process, for an example, we can refer to it by its PID. As each PID is unique, there is no ambiguity or risk of accidentally killing the wrong process (unless you enter the wrong PID).If we open top (in a terminal, type top and press enter), the ... Read More

The IP address range 127.0.0.0 – 127.255.255.255 is reserved for loopback. Loopback IP address is managed entirely by and within the operating system. These addresses enable the Server and Client processes on a single system to communicate with each other. When a process creates a packet with destination address as loopback address, the operating system loops it back to itself without having any interference of NIC.Data sent on loopback is forwarded by the operating system to a virtual network interface within operating system. This address is mostly used for testing purposes like client-server architecture on a single machine.For example, if ... Read More

Context Switching involves storing the context or state of a process or thread so that it can be reloaded when required and execution can beresumed from the same point as earlier. This is a feature of a multitasking operating system and allows a single CPU to be shared by multiple processes.A process switch or process scheduling is to changing one process from another by saving all of the state of the currently executing process, including its register state, associated kernel state, and all of its virtual memory configuration.A thread switch means switching from one thread to another thread within a ... Read More