alco 2.5.2

Autonomous Log Collector and Observer

What’s the problem

There is a widely used stack of technologies for parsing, collecting and analysing logs - ELK Stack. It has very functional web interface, search cluster and a log transformation tool. Very cool, but:

• It’s Java with well-known requirements for memory and CPUs

• It’s ElasticSearch with it’s requirements for disk space

• It’s Logstash which suddenly stops processing logs in some conditions.

• It’s Kibana with very cool RICH interface which looses on all counts to grep and less in a task of log reading and searching.

Introducing ALCO

ALCO is a simple ELK analog which primary aim is to provide a online replacement for grep and less. Main features are:

• Django application for incident analysis in distributed systems

• schemeless full-text index with filtering and searching

• configurable log collection and rotation from RabbitMQ messaging server

• not a all-purpose monster

Technology stack

Let’s trace log message path from some distributed system to ALCO web interface.

1. Python-based project calls logger.debug() method with text ‘hello world’

2. At startup time Logcollect library automatically configures python logging (or even Django and Celery one’s) to send log messages to RabbitMQ server in JSON format readable both with ELK and ALCO projects.

3. ALCO log collector binds a queue to RabbitMQ exchange and processes messages in a batch.

4. It uses Redis to collect unique values for filterable fields and SphinxSearch to store messages in a realtime index.

5. When a message is inserted to sphinxsearch, it contains indexed message field, timestamp information and schemeless JSON field named js with all log record attributes sent by python log.

6. Django-based web interface provides API and client-side app for searching collected logs online.

Requirements

• Python 2.7 or 3.3+

• Logcollect for python projects which logs are collected

• RabbitMQ server for distributed log collection

• SphinxSearch server 2.3 or later for log storage

• Redis for SphinxSearch docid management and field values storage

• django-sphinxsearch as a database backend for Django>=1.8 (will be available from PyPI)

Setup

1. You need to configure logcollect in analyzed projects (see README). If RabbitMQ admin interface shows non-zero message flow in logstash exchange - “It works” :-)

2. Install alco and it’s requirements from PyPi

   pip install alco

3. Next, create django project, add sphinxsearch database connection and configure settings.py to enable alco applications

   # For SphinxRouter
   SPHINX_DATABASE_NAME = 'sphinx'
   
   DATABASES[SPHINX_DATABASE_NAME] = {
         'ENGINE': 'sphinxsearch.backend.sphinx',
         'HOST': '127.0.0.1',
         'PORT': 9306,
     }
   }
   
   # Auto routing log models to SphinxSearch database
   DATABASE_ROUTERS = (
     'sphinxsearch.routers.SphinxRouter',
   )
   
   INSTALLED_APPS += [
   'rest_framework', # for API to work
   'alco.collector',
   'alco.grep'
   ]
   
   ROOT_URLCONF = 'alco.urls'

4. Configure ALCO resources in settings.py:

   ALCO_SETTINGS = {
     # log messaging server
     'RABBITMQ': {
         'host': '127.0.0.1',
         'userid': 'guest',
         'password': 'guest',
         'virtual_host': '/'
     },
   
     # redis server
     'REDIS': {
         'host': '127.0.0.1',
         'db': 0
     },
     # url for fetching sphinx.conf dynamically
     'SPHINX_CONF_URL': 'http://127.0.0.1:8000/collector/sphinx.conf',
     # name of django.db.connection for SphinxSearch
     'SPHINX_DATABASE_NAME': 'sphinx',
     # number of results in log view API
     'LOG_PAGE_SIZE': 100
   }
   
   # override defaults for sphinx.conf template
   ALCO_SPHINX_CONF = {
     # local index definition defaults override
     'index': {
       'min_word_len': 8
     },
     # searchd section defaults override
     'searchd': {
       'dist_threads': 8
     }
   }

5. Run syncdb or better migrate management command to create database tables.

6. Run webserver and create a LoggerIndex from django admin.

7. Created directories for sphinxsearch:

   /var/log/sphinx/
   /var/run/sphinx/
   /data/sphinx/

8. Next, configure sphinxsearch to use generated config:

   searchd -c sphinx_conf.py

   sphinx_conf.py is a simple script that imports alco.sphinx_conf module which fetches generated sphinx.conf from alco http api and created directories for SphinxSearch indices:

   #!/data/alco/virtualenv/bin/python
   
   # coding: utf-8
   import os
   os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'settings')
   
   from alco import sphinx_conf

9. Run log collectors:

   python manage.py start_collectors --no-daemon

   If it shows number of collected messages periodically - then log collecting is set up correctly.

10. Configure system services to start subsystems automatically:

    • nginx or apache http server

    • django uwsgi backend

    • alco collectors (start_collectors management command)

    • sphinxsearch, redis, default database for Django

11. Open http://127.0.0.1:8000/grep/<logger_name>/ to read and search logs online.

Virtualenv

We successfully configured SphinxSearch to use python from virtualenv, adding some environment variables to start script (i.e. FreeBSD rc.d script):

sphinxsearch_prestart ()
{
    # nobody user has no HOME
    export PYTHON_EGG_CACHE=/tmp/.python-eggs
    # python path for virtualenv interpreter should be redeclared
    export PYTHONPATH=${venv_path}/lib/python3.4/:${venv_path}/lib/python3.4/site-packages/
    . "${virtualenv_path}/bin/activate" || err 1 "Virtualenv is not found"
    echo "Virtualenv ${virtualenv_path} activated: `which python`"

}

In this case shebang for sphinx_conf.py must point virtualenv’s python interpreter.

Production usage

For now ALCO stack is tested in preproduction environment in our company and is actively developed. There are no reasons to say that it’s not ready for production usage.