Install Nagios Core from RPM on CentOS 7 / RHEL 7

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Nagios is a free software, which offers monitoring and alerting services for servers, switches, applications and services.

This tutorial describes simple Nagios Core and Nagios Plugins installation from rpm packages on CentOS 7 / RedHat 7. There is no need to configure and compile Nagios Core tar.gz based source files unless you really need the newest version.
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OpenStack Kilo 3 Node Installation (Controller, Network, Compute) on CentOS 7

install openstack on three nodes
In this tutorial we will install OpenStack Kilo release from RDO repository on three nodes (Controller, Network, Compute) based on CentOS 7 operating system using packstack automated script. The following installation utilizes VLAN based internal software network infrastructure for communication between instances.

Environment used:
public network (Floating IP network): 192.168.2.0/24
internal network (on each node): no IP space, physical connection only (eth1)
controller node public IP: 192.168.2.12 (eth0)
network node public IP: 192.168.2.13 (eth0)
compute node public IP: 192.168.2.14 (eth0)
OS version (each node): CentOS Linux release 7.2.1511 (Core)
install openstack on 3 nodes
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Register Red Hat 7 using Subscription Manager via Proxy

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Once our Red Hat 7 system is installed, it should be registered at RHN using Subscription Manager in order to be able to get newest updates. If the server is placed in network behind firewall and outgoing traffic is blocked by firewall, the only reliable way of keeping our Red Hat 7 up-to-date is through proxy (if any exists).
Below we will show you in 2 simple steps, how to configure HTTP Proxy for Red Hat Subscription Manager and register Red Hat 7 with RHN in command line using HTTP Proxy:
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nethogs – Display Network Utilization per Process

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Have you ever wondered how to check network utilization by PID in Linux? Now it’s easy with nethogs application, which unlike other network utilization monitoring applications (nload, iftop) works like Linux top command, but displays network utilization per PID along with the network device used.

nethogs
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