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Archives pour la catégorie ‘Système’

How do I change, sort, add, remove graphs with Munin?

19/02/2019 Aucun commentaire

Graphs on Munin

Enable and disable plugins on each node

graphs muninGraphs are added and removed via symlinks in the /etc/munin/plugins/ directory of the node.

To remove a graph you must remove the symlink and restart the node:

rm /etc/munin/plugins/diskstats
service munin-node restart

To add a graph you must add a symlink in the plugins directory to an executable. eg:

ln -s /usr/share/munin/plugins/diskstats /etc/munin/plugins/diskstats
service munin-node restart

When you restart munin-node it runs immediately and any issues with the plugins appears in /var/log/munin/munin-node.log. If all is going well you’ll see a CONNECT logged every cycle; this records the fact that the master connected to collect the latest data.

Process Backgrounded
2014/03/10-15:59:47 Munin::Node::Server (type Net::Server::Fork) starting! pid(32231)
Resolved [*]:4949 to [::]:4949, IPv6
Not including resolved host [0.0.0.0] IPv4 because it will be handled by [::] IPv6
Binding to TCP port 4949 on host :: with IPv6
2014/03/10-16:00:04 CONNECT TCP Peer: "[::ffff:203.28.51.227]:45965" Local: "[::ffff:50.23.111.122]:4949"
2014/03/10-16:05:04 CONNECT TCP Peer: "[::ffff:203.28.51.227]:46109" Local: "[::ffff:50.23.111.122]:4949"
2014/03/10-16:10:04 CONNECT TCP Peer: "[::ffff:203.28.51.227]:46109" Local: "[::ffff:50.23.111.122]:4949"

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An lsof Primer

15/02/2019 Aucun commentaire

Source: Daniel Miessler

lsof

lsof is the sysadmin/security über-tool. I use it most for getting network connection related information from a system, but that’s just the beginning for this powerful and too-little-known application. The tool is aptly called lsof because it “lists open files“. And remember, in UNIX just about everything (including a network socket) is a file.

Interestingly, lsof is also the Linux/Unix command with the most switches. It has so many it has to use both minuses and pluses.

usage: [-?abhlnNoOPRstUvV] [+|-c c] [+|-d s] [+D D] [+|-f[cgG]]
 [-F [f]] [-g [s]] [-i [i]] [+|-L [l]] [+|-M] [-o [o]]
 [-p s] [+|-r [t]] [-S [t]] [-T [t]] [-u s] [+|-w] [-x [fl]] [--] [names]

As you can see, lsof has a truly staggering number of options. You can use it to get information about devices on your system, what a given user is touching at any given point, or even what files or network connectivity a process is using.

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Categories: Système Tags: ,

Installing A High Availability Web Server Cluster On Ubuntu 12.10 Using HAProxy, HeartBeat And Lampp

14/02/2019 Aucun commentaire

What is the main objective of this entire topology?

high availability web server clusterRedundancy and Load Sharing! Imagine a scenario where your single web server is receiving millions and millions of HTTP requests per second, the CPU load is going insane, as well as the memory usage, when suddenly “crash!”, the server dies without saying good-bye (probably because of some weird hardware out-stage that you certainly won’t have time to debug). Well, this simple scheme might lead you into a brand new world of possibilities

What is this going to solve?

Hardware Failures! We are going to have redundant hardware all over the place, if one goes down, another one will be immediately ready for taking its place. Also, by using load sharing schemes, this is going to solve our High Usage! issue. Balancing the load among every server on our “farm” will reduce the amount of HTTP request per server (but you already figured that out, right?).
Let’s set it up! Firstly, we’re not going to use a domain scheme (let’s keep it simple), make sure your /etc/hosts file looks exactly like the picture below on every machine:
#vi /etc/hosts
192.168.0.241   haproxy
192.168.0.39 Node1
192.168.0.30 Node2
192.168.223.147 Node1
192.168.223.148 Node2
192.168.0.58 Web1
192.168.0.139 Web2
192.168.0.132 Mysql

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Categories: Système Tags: ,

Installing a high availability web server cluster on Ubuntu 12.04 LTS using HAProxy, HeartBeat and Nginx

14/02/2019 Comments off

How to set-up a high-availability cluster

Here are a few notes about how to set-up a high-availability web server farm using Ubuntu 12.04 LTS using a whole load of awesome software (HAProxy, HeartBeat, Watchdog and Nginx)

The setup

In my setup I have five virtual machines, these are named and used for the following:-

haproxy1 – Our first proxy (master)/load-balancer (running HAProxy, HeartBeat and Watchdog) [IP address: 172.25.87.190]
haproxy2 – Our second proxy (failover)/load-balancer (running HAProxy, HeartBeat and Watchdog) [IP address: 172.25.87.191]
web1 – Our first web server node (running nginx) [IP address: 172.25.87.192]
web2 – Our second web server node (running nginx) [IP address: 172.25.87.193]
web3 – Our third web server node (running nginx) [IP address: 172.25.87.194]

The servers are connected in the following way:-

thesetup

In my next post I will also explain how to configure the web servers to point to a backend shared storage cluster (using NFS) and a MySQL cluster server to have a truly highly available web hosting platform.

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Categories: Système Tags: , , ,

Automating the Deployment of a Scalable WordPress Site

12/02/2019 Aucun commentaire

Introduction

In this guide we will create and deploy a scalable WordPress instance consisting of a MySQL database server, a GlusterFS distributed filesystem, Nginx web servers and an Nginx load balancer. By using user-data and droplet meta-data we will automate the deployment of our site. Finally we will provide a Ruby script which will automate this entire process and ease the creation of scalable WordPress sites. Through this tutorial you will learn about the power and flexibility of user-data and droplet meta-data in deploying services on DigitalOcean.

Step One – Planning our Deployment

The deployment we create in this tutorial will consist of a single MySQL database server, multiple GlusterFS servers in a cluster, multiple Nginx web servers and a single Nginx load balancer.

WordPress Deployment

Before we begin we should know:

  • What size droplet we will use for our MySQL server
  • How many GlusterFS nodes we will create
  • What size our GlusterFS nodes will be
  • How many web server nodes we will need
  • What size droplets we will use for our web servers
  • What size droplet we will use for our load balancer
  • The domain name we will use for our new site

We can add additional nodes or scale up the nodes we created if we need to later. Once we have decided on these details we can begin deploying our site.

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