Forward connection to local development environment in LAN

I needed a quick way to test a few things on a webapp running locally (on my Linux box) from another machine running Mac OSX.

Quick and easy way (although insecure, make sure you only do this on a private LAN) was to use socat.

Install on Archlinux (server):

sudo pacman -S socat

Install on the MacOSX client via homebrew:

brew install socat

Proxy local connection to the LAN (on the server; assuming the webapp runs locally on port 5000):

socat tcp-listen:8000,fork tcp:localhost:5000

Proxy remote connection to localhost (so we can access it with the benefits ...

Deploying an Elasticsearch cluster via SaltStack

Here is a short guide covering the steps I followed in order to deploy an ElasticSearch cluster using SaltStack to manage configuration.


For the purposes of testing, I will be using a bunch of locally-installed virtualmachines. Specifically, we'll have:

  • A machine running salt master
  • Three elasticsearch nodes

Creating the VMs

To create the machines, I just installed a bare-bones wheezy image (under KVM) and cloned it four times:

virt-clone -o TemplateWheezy -n es-cluster-salt-master -f /mnt/virtualmachines/es-cluster-salt-master.img -m '52:54:00:ee:55:f0'
for id in 01 02 03; do
    virt-clone -o TemplateWheezy -n es-cluster-node-"$id ...

Using nvidia driver on debian jessie

I had some troubles getting nvidia proprietary drivers up & running on Debian Jessie (kernel 3.13-1-amd64).

I'm sharing the solution I found here, as it might be useful to somebody else.

Machine configuration

Machine: Thinkpad W530
Graphics card: NVIDIA Corporation GK107GLM [Quadro K2000M] (rev a1)
Operating System: Debian Jessie (testing) - amd64
Kernel: 3.13-1-amd64 (3.13.10-1)

The error message I got:

[   36.508494] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
[   36.508500] NVRM: os_pci_init_handle: invalid context!
[   36.508502] NVRM: os_pci_init_handle: invalid context!
[   36.508507] NVRM: GPU at 0000:01:00.0 has fallen ...

Importing Apache logs in ElasticSearch

I needed some way to visualize and analyze logs from webservers.

So, I decided to use the "elasticsearch stack" for that:

Setting up ElasticSearch

Just download, untar and launch:

tar xzvf elasticsearch-1.1.1.tar.gz
cd elasticsearch-1.1.1

Check if everything is ok:

http localhost:9200

Importing logs to ElasticSearch

I used LogStash to import the logs from file to ElasticSearch. That required a bit of configuration.

First, download & unpack logstash:

wget ...

Using HTTPS with self-signed certificate in nginx

I recently needed to enable https support on a nginx server, using self-signed certificates. This is roughly the procedure I followed to:

  • Create a CA siging certificate
  • Create a delegate CA certificate for the actual signing
  • Generate a certificate signing request
  • Sign the request generating the final certificate

Generating the CA certificate

First of all, generate the master CA certificate:

# Create the CA key
openssl genrsa -des3 -out ca.orig.key 4096

# Remove passphrase from CA key (optional)
openssl rsa -in ca.orig.key -out ca.key

# Create certificate (will create signing request + sign it)
openssl req -new -x509 -days ...

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