The PDF Version

#html #cheatsheet

https://askubuntu.com/questions/726601/nethogs-%E2%86%92-creating-socket-failed-while-establishing-local-ip-are-you-root

#nethogs #debian #linux #bug

How do you upgrade Icinga2 from a very old version?

The short answer is that you need to do an incremental upgrade on its database.

But how exactly?

apt-get update

apt-cache policy icinga2-ido-mysql

The candidate section displays what version is available for you system. Do the same for icingaweb2:

apt-cache policy icingaweb2

Upgrade these packages alltogether:

apt-get upgrade -o Dpkg::Options::="--force-confold" -y

Update icinga2 packages:

apt-get upgrade icinga2 icinga2-bin icinga2-common icinga2-ido-mysql libicinga2
 apt-get install icinga2-bin
 apt-get install icinga2

Now check icinga2 log in tail -f /var/log/icinga2/icinga2.log, you may see errors like:

[2017-12-21 12:00:22 -0600] critical/IdoPgsqlConnection: Schema version '1.14.2' does not match the required version '1.14.3' (or newer)! Please check the upgrade documentation at https://docs.icinga.com/icinga2

Here you need to upgrade MySQL schemas, go to /usr/share/icinga2-ido-mysql/schema/upgrade path and now import new schemas to Icinga2 MySQL database. As I was in version 2.6.0 I went for 2.8.0:

mysql -u icinga2 -p icinga2 < 2.8.0.sql

It will prompt for password of user icinga2, enter the password and go on.

The content of MySQL Schemas is as follows:

2.0.2.sql  2.1.0.sql  2.2.0.sql  2.3.0.sql  2.4.0.sql  2.5.0.sql  2.6.0.sql  2.8.0.sql  2.8.1.sql

NOTE: to get the password for user icinga2 open /etc/icinga2/features-enabled/ido-mysql.conf file and get the password from here.


#linux #icinga2 #monitoring #icinga2 #icingaweb #upgrade

How to get list of network interfaces using nagios?

In nagios plugins there is a script called check_nwc_health that can be used to report network interfaces of a remote server. In order to check interface usage of remote server network cards:

cd /usr/lib/nagios/plugins
 ./check_nwc_health --mode interface-usage -H 172.17.131.12 -C YOUR_COMMUNITY_STRING

Give your host address in -H section and your community string in -C param.

#nagios #network #network_usage

The best explanation about load average:

http://blog.scoutapp.com/articles/2009/07/31/understanding-load-averages

#linux #load #load_average #cpu

In case your upgrade failed, try to start icinga service and in the meantime check the logs in another console:

service icinga2 start

Check logs to see what is the error:

tail -f /var/log/icinga2/icinga2.log

If it point to a specific config file, change the config as reported or in case you don't need it remove it. It happened for me on another Icinga2 server and I removed the old config and tried to apply the new schemas. It gave another error on mysql grants, I gave all permissions to the icinga2 user:

mysql -u root -p
 GRANT ALL PRIVILEGES ON icinga2_database_name.* TO 'icinga2_username'@'localhost'
 flush privileges;

Now all things should be up and working now.

#icinga2 #monitoring #upgrade #schema_update #icinga

Generate random valid users agent for your bot crawlers in Python:

https://pypi.org/project/user_agent/

#python #user_agent #crawl #web_scraper

How to Load & Parse YAML file in Python?

To install YAML library:

pip install pyyaml

To load a YAML file:

>>> import yaml
 >>> print yaml.load("""
 ... name: Vorlin Laruknuzum
 ... sex: Male
 ... class: Priest
 ... title: Acolyte
 ... hp: [32, 71]
 ... sp: [1, 13]
 ... gold: 423
 ... inventory:
 ... - a Holy Book of Prayers (Words of Wisdom)
 ... - an Azure Potion of Cure Light Wounds
 ... - a Silver Wand of Wonder
 ... """)

To convert a dictionary to a YAML file:

>>> print yaml.dump({'name': "The Cloak 'Colluin'", 'depth': 5, 'rarity': 45, 'weight': 10, 'cost': 50000, 'flags': ['INT', 'WIS',     'SPEED', 'STEALTH']})

#python #yaml #pyyaml #load #dump

How to localize a UTC date?

import pytz
 import datetime

 date_format = '%Y-%m-%d %H:%M:%S'
 dt = datetime.datetime.strptime('2018-12-12 00:00:00', date_format)
 utc_tz = pytz.timezone('UTC')
 utc_d = utc_tz.localize(dt)
 teh_tz = pytz.timezone('Asia/Tehran')
 dt = utc_d.astimezone(teh_tz)

#localize #timezone #pytz #astimezone #replace

#ebook #download #sql #postgreql #pdf

#pdf #ebook #postgresql

https://developer.mozilla.org/en-US/docs/Learn/Server-side/Django

#django #tutorial #mozilla

ngrok something that ROCKS and is priceless!

As ngrok itself says:

Public URLs for exposing your local web server

Have you had an experience of when you need to test a tool and the 3rd party needs you to give a public accessible URL? Well, what would you do when you are developing a project on your PC, Laptop? You don't have any URL to give to 3rd party tools. Here ngrok truely rocks!

Downlaod it from the URL below:

https://ngrok.com/

And extract the download binay for your OS. In order to run the ngrok just do like below:

./ngrok http 5000

The above command will output some data and a part which is Forwarding for http and https:

Forwarding                    http://76eec0f8.ngrok.io -> localhost:5000
 Forwarding                    https://76eec0f8.ngrok.io -> localhost:5000

The URL 76eec0f8.ngrok.io is the part that you will give to the 3rd party. and all the other part of the URL path will be forwarded
to port 5000 on your local server.

Yes, I know it's like a magic.

#ngrok #port #http #ngrok_io

https://stackoverflow.com/questions/23554872/why-does-pycharm-propose-to-change-method-to-static

#python #pycharm #static #staticmethod

Why some sites does not show in iFrame HTML tag?

The first reason you need to check is to make sure that you are not loading an HTTP website from within an HTTPS website, otherwise
you will get and error. You can see the error by using your browser Developer Tools -> Console.

If you are loading an HTTPS from inside of HTTPS and it is not loading, then take a look at the header X-Frame-Option in response header. If it exists it probably has avalue of either DENY or SAMEORIGIN.

DENY: No one can load the website in iframe. Even the same domain page wont be able to load.

SAMEORIGIN: only a page which is in same domain can load this website in iframe.

#html #iframe #X_Frame_Option

#template #idea

#template #idea

I sometimes forgot to pull data from git before start working on a project. To minimize the headache of merge conflict or having to reset head and stash your data you can set a cronjob to run every 10 minute or so. And inside of your bash script CD into eaach of your folders and issue git pull command.

If you have similar issues and you're solving it in a different manner, I'd be happy to hear about it. :)

#linux #mac #bash #script #git #cron #crontab #cronjob