How to install the latest node.js on Ubuntu

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How to install the latest node.js on Ubuntu?

 

Linux IPv6 Router: RADVD + DHCPv6

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Unlike IPv4, which uses DHCP for configuration, IPv6 uses the Neighbor Discovery Protocol to configure addresses and gateways. Unfortunately, originally the protocol had no means of providing addresses of DNS servers to clients, making it necessary to use  DHCPv6 for that purpose. Modern Linux and Mac OS X machines are able to use the IPv6 Router Advertisement Options for DNS Configuration (RFC 6106), but to my knowledge, Windows clients are not able at the moment. Here’s how to configure a Linux router using radvd and the ISC DHCP daemon. Continue reading Linux IPv6 Router: RADVD + DHCPv6

PostgreSQL Database Cluster Migration Notes

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I had to migrate a pretty big database cluster from one server with PostgreSQL 8.4 to a new server with 9.2 There we multiple apps using the databases, and the downtime had to be minimal. Luckily, the databases were split to multiple schemas, and there were only a few tables in a couple of schemas that were in active use at the time of the migration.

The pg_dump tool was very helpful in this operation. First, I set up ssh public key authentication between the postgres users from the source to the destination server. Then I ran the first full cluster dump to the new empty cluster. This can be done while users are actively using the source database, as long as you know which schemas, tables and sequences are in use, so that they can be copied again after shutting down applications: Continue reading PostgreSQL Database Cluster Migration Notes

Sonera CStream Messaging Web Service API with Python and SUDS

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In this article I will show you how to use the Sonera CStream Messaging Web Service API to send an SMS using Python, and a library called  SUDS. The CStream API is two-way service for both sending and receiving messages. You obviously need to pay for the service to get access. After you have your credentials, you can start using the service.

The SUDS is a lightweight SOAP Python client for exploring and using web services. A recent version can be installed on Debian based distros with “sudo apt-get install python-suds”, or on almost anything with “pip install suds”. Continue reading Sonera CStream Messaging Web Service API with Python and SUDS

Init Script for Daemonizing Non-Forking Processes

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Sometimes you have an executable which does not fork to the background, but you need to control it with init scripts, so that it does indeed run in the background. Here’s a pretty generic init script for that. It allows you to configure these:

Continue reading Init Script for Daemonizing Non-Forking Processes

HP ProLiant Management Component Pack on Ubuntu

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HP seems to have set up a package repository for Ubuntu 12.04, which is an improvement since I last checked a few years ago. To use the repo, add the following line to /etc/apt/sources.list:

Run “sudo apt-get update”.

You can install a number of software packages from the repository:

  • hpsmh: HP System Management Homepage
  • hp-smh-template: HP System Management Homepage Templates
  • cpqacuxe: HP Array Configuration Utility, web-based
  • hp-snmp-agents: Insight Management SNMP Agents for HP ProLiant Systems
  • hponcfg: RILOE II/iLO online configuration utility
  • hp-health: HP System Health Application and Command line Utility Package
  • hpacucli: HP Command Line Array Configuration Utility
  • ams: Agentless Monitoring Service for HP ProLiant Gen8 Systems Continue reading HP ProLiant Management Component Pack on Ubuntu

HP iLO2 Virtual Serial Console on Ubuntu

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To get a virtual serial console, you need to enable the iLO virtual serial port. I had mine set up like this:

  • iLO 2 Virtual Serial Port: COM2 0x2F8 IRQ 3

I also enabled ssh access in the iLO web interface. This way I can ssh into the iLO and see all BIOS messages using the “vsp” command. I can even go to the BIOS setup (RBSU) by pressing “ESC-9”.

To be able to control GRUB via the virtual serial port, it has to be configured. I changed the following lines in /etc/default/grub: Continue reading HP iLO2 Virtual Serial Console on Ubuntu

Upgrading HP Proliant iLO2 Firmware with Ubuntu Server

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I downloaded the firmware from HP site. It was named CP019022.scexe. I tried uploading it in the iLO2 web interface, but it was rejected. Next, I copied it to the server, gave it execute permissions and ran it:

Not working. This is a fresh installation of Ubuntu Server 12.04.2 LTS x86_64. So I had to start looking closer. The file is a bash script but the hashbang is #!/bin/sh, which puts bash into old Bourne shell mode. No pushd/popd there. Continue reading Upgrading HP Proliant iLO2 Firmware with Ubuntu Server

Web Messaging with RabbitMQ-Web-Stomp and SockJS

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In this article, I will discuss sending messages from server to web browser using RabbitMQ-Web-Stomp as the backend, and a simple JavaScript library to handle the web browser side. SockJS is used as the browser WebSockets library. This setup enables you to directly push messages in realtime from the RabbitMQ message broker to the web client. This makes it possible to deliver status updates to multiple web clients directly from the message broker. No need for special application server software in the middle.

The reverse is also possible. You can push messages from web browsers directly into the RabbitMQ routing system. This article, though, will discuss the former case, from server to client. The infrastructure required for the latter case is the same, with nothing extra needed. Continue reading Web Messaging with RabbitMQ-Web-Stomp and SockJS

Temporarily Disable PostgreSQL Triggers

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To temporarily disable all triggers in a PostgreSQL session, use this:

That disables all triggers for the current database session only. Useful for bulk operations, but remember to be careful to keep your database consistent.

To re-enable:

Disable a Single Trigger

To disable just a single trigger, use ALTER TABLE:

The difference to the previous method is that ALTER TABLE will globally disable the trigger, affecting all database sessions, not just the current one.

To disable all triggers for one table:

To re-enable:

 

Ubuntu 12.04 Active Directory Authentication

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Update 2015-06-16: Ubuntu 14.04 Active Directory Authentication

Authenticating Linux users against Active Directory has traditionally been hard. There’s a multitude of HOWTOs on how to do it, and every one of them seems to do it a bit differently. This is because environments and goals vary, and there are many ways to achieve a particular goal. I will add my version to the mix. This one fetches users and groups from Active Directory LDAP using a machine account added using the Samba tools, and authenticates users to the Active Directory Key Distribution Center using Kerberos. Continue reading Ubuntu 12.04 Active Directory Authentication

Checking PostgreSQL Disk Usage

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This query sums total disk space used by the table including indexes and toasted data for the 20 largest tables:

via Disk Usage – PostgreSQL wiki.

Apache HTTP authentication against WordPress password database

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The stock mod_auth_mysql package in Ubuntu is not able to authenticate against the phpass password hashes stored in the WordPress database.

There seems to be a patch lying around to enable phpass authentication in mod_auth_mysql. Its inclusion in mod_auth_mysql has been requested a long time ago, and again more recently, but for one reason or another it has been declined. Inclusion of the patch into the Debian package has also been requested.

Thanks to Peter Lamberg, there are good instructions around on how to apply the patch and enable it. I’ve made available a pre-compiled 64-bit package here: Continue reading Apache HTTP authentication against WordPress password database