Simple CURL based monitoring system.
Project description
Installation
Requirements
Selena requires Python 2.7 which is included in the latest Ubuntu Server 12.04 LTS systems:
$ sudo apt-get install python-dev python-virtualenv
Message queue
Selena communicates with a central queue with Redis as the broker. Install redis:
$ sudo apt-get install redis-server
Since lost tasks can always be resent, the durability guarantees that Redis provides by default are not necessary. You can significantly speed up the queue by commenting out the save lines from /etc/redis/redis.conf.
We can check the status of the Redis server:
$ redis-cli -h localhost -p 6379 -n 0 info
Virtual Environment
Let’s create a virtual environment for Python in the user’s home:
$ virtualenv . --distribute --no-site-packages
System User
Unprivileged and not owned by a person:
$ sudo adduser --home /home/selena selena $ sudo su - selena
In any shell the user can activate the virtual environment. As a result of that, the default Python executable and helper scripts will point to those within the virtualenv directory structure:
$ which python /usr/local/bin/python $ . bin/activate (selena)$ which python /home/selena/bin/python
Database
Selena uses and supports MySQL. To install MySQL invoke:
$ sudo apt-get install mysql-server libmysqlclient-dev libmysqld-dev
You now have to create a database and a user for Selena system. You can find many tutorials for that on the Internet.
Cache
Selena requires some cache system like memcached. Install:
$ sudo apt-get install memcached
Installing from pip
Simply invoke:
(selena)$ pip install selena
Installing from sources
Alternatively, to live on the bleeding edge, you can clone the selena git repository to project and install it manually:
(selena)$ git clone git://github.com/allegro/selena.git project (selena)$ cd project (selena)$ pip install -e .
Selena Agent
To function properly, Selena needs Selena-agent package installed and configured.
Configuration
Create file /INSTALL_DIR/selena/settings-local.py and fill in the appropriate data.
Fill MySQL connection data:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'your database name',
'USER': 'your database username',
'PASSWORD': 'your database password',
'HOST': 'localhost',
'PORT': '3306',
'OPTIONS': {
'init_command': 'SET storage_engine=INNODB,character_set_connection=utf8,collation_connection=utf8_unicode_ci'
}
}
}
Generate new secret keys:
SECRET_KEY = 'very_unique_string' AES_SECRET_KEY = b'sixteen byte key'
Set the number of minutes that will be displayed by the service errors, example 30:
ERROR_TIME_INTERVAL = 30
Define RQ queues. The default queue is required. You have to also define one queue for main selena agent, for example agent_1:
RQ_QUEUES = {
'default': {
'HOST': '127.0.0.1', # Redis host
'PORT': 6379, # Redis port
'DB': None,
'PASSWORD': None,
},
'agent_1': {
'HOST': '127.0.0.1',
'PORT': 6379,
'DB': None,
'PASSWORD': None,
},
}
You can define additional queues: planner, archiving, dispacher, monitors, stats. They are used as follows:
planner - enable or disable planned technical breaks
archiving - create partitions, archive data
dispacher - run monitoring tasks for services
monitors - collect results from agents
stats - calculate statistics
You also have to configure cache. Sample cache configuration (for default memcached configs):
CACHES = {
'default': {
'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
'LOCATION': '127.0.0.1:11211',
}
}
Database preparation
After creating the settings-local.py file, synchronize the database with sources by running the standard syncdb management command:
$(selena): selena syncdb
then run migrations command:
$(selena): selena migrate
Create partitions in the database by using the command:
$(selena): selena createpartitions
Run web interface
To run selena web interface use the command:
(selena)$ selena runserver 8080
Configuration agents
When your selena web interface is running you must add a main agents to your selena instance. Open this link in your browser http://localhost:8080/admin/services/agent/add/ and log in into administration panel.
You will see a form where you have to fill the name of your main agent, add a queue (remember the name of the queue must be set in your Selena agent settings-local.py file), and check the main agent checkbox. After the agent is added you will see Salt column in your agent row. Copy this string and add to the Selena-agent settings-local.py file in SALT variable. It is very important, because without it there will be no communication with the Selena-agent.
Add monitored services
In administration panel add a service which will be monitored by Selena. Open this link in browser http://localhost:8080/admin/services/service/add/ and add a service URL to be monitored.
Commands
Run a single monitoring service:
(selena)$: selena monitorall
Search incidents:
(selena)$: selena searchincidents
Activate/Deactivate technical breaks:
(selena)$: selena technicalbreaks
For optimization, there are commands to archive service monitoring results. If you create partitions in MySQL database run command:
(selena)$: selena createpartitions
You will need to run the command that merges monitoring data older than 8 days and moves it to the archive:
(selena)$: selena makearchive
If you want to run the commands asynchronically, you can add an --async-mode=1 option to them.
Automation
You can configure Cron to monitor automatically in background. To edit crontab run command:
$(selena): crontab -e
and add this content:
*/1 * * * * /YOUR_VIRTUAL_ENV_PATH/bin/selena monitorall */1 * * * * /YOUR_VIRTUAL_ENV_PATH/bin/selena searchincidents --async-mode=1 */5 * * * * /YOUR_VIRTUAL_ENV_PATH/bin/selena technicalbreaks --async-mode=1 0 1 * * * /YOUR_VIRTUAL_ENV_PATH/bin/selena createpartitions --async-mode=1 30 1 * * * /YOUR_VIRTUAL_ENV_PATH/bin/selena makearchive --async-mode=1
Of course you can set your own time to execute these commands in Cron.
To see the results of the monitoring in a browser, open the following address: http://localhost:8080
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