Docker Tutorials

Basic Tutorials:

1. Docker Build: A Beginner’s Guide to Building Docker Images
2. Docker Curriculum
3. Awesome Docker

Docker Volume: 

1. Understanding Docker Volumes with an example 
2. Docker Tutorial Series : Part 7 : Data Volumes [recommended]

General and comprehensive  Tutorial:

1. Docker Tutorial Series (Recommended,  there are a lot of content)
2. Container Tutorials (Looks like a really good resources)

Configure docker image autorestart:

# In order to enable a restart policy, you need to use the --restart argument when executing docker run
docker run -dit --restart unless-stopped httpd

# Or configure a running container
# unless-stopped: The container would always be restarted unless it was manually stopped
docker update --restart unless-stopped container_id

• How to Start Docker Containers Automatically After a Reboot? 
  

Content from Docker Tutorial Series : 

Part 1 — Installation

Part 2 — Basic Commands

Part 3 — More on Images and Containers

Part 4 — Docker Hub

Part 5 — Building your own Docker Images

Part 6 — Docker Private Registry

Part 7 — Data Volumes

Part 8 — Linking Containers

Part 9 — Writing a Dockerfile

Part 10 — Docker Swarm Tutorial

Part 11 — Docker Swarm on Google Compute Engine

Part 12 — Getting Started with Kubernetes using Minikube

Part 13 — Docker Management Commands

Appendix

Docker : Learning Resources

Docker Use Cases

Learning Docker ? Move To The Cloud !

An Introduction to Firewalld

Refer to An Introduction to Firewalld

Add a Port for TCP or UDP

You do have to specify TCP or UDP and to open a port for both. You will need to add rules for each protocol.

firewall-cmd --permanent --add-port=443/tcp

Saving Firewall Rules

After you have completed all the additions and subtraction of rules, you need to reload the firewall rules to make them active. To do this, you again use the firewall-cmd tool but using the option –reload.

firewall-cmd --reload

Config to accept all traffic between the nodes:

[root@mgt ~]$ firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT 0 -s  192.168.x.xxx -j ACCEPT
success
[root@mgt ~]$ firewall-cmd --reload
success

Refer to add rule to firewalld in Centos7 to allow all traffic from a server 

Syntax highlight in html pre code block

Check here: highlight.js

and Stackoverflow

Learning Web Development

Refer to 

• How Long Does It Take to Learn Web Development and Get a Job?
  

Django: Highlight Search Results

Solution refer to below links

• stackoverflow: how-to-highlight-searched-queries-in-result-page-of-django-template
  
• Custom template tags and filters
• Highlight matched search term
  

Python re.sub() case insensitive replace coding example: 

In [54]: re.sub('(%s)'%re.escape('hE'), r'<abc>\g<1></abc>', 'hello', flags=re.IGNORECASE)
Out[54]: '<abc>he</abc>llo'


In [56]: re.sub('(%s)'%re.escape('hE.'), r'<abc>\g<1></abc>', 'he.llo', flags=re.IGNORECASE)
Out[56]: '<abc>he.</abc>llo'

Or another version (Here we exclude URL replacement from HTML text): 

    pattern = re.compile('(^%s|[\s]%s|%s[\s])' % tuple([re.escape(word),]*3), re.IGNORECASE)
    highlighted = pattern.sub(r'<span class="highlight">\g<1></span>', highlighted)

Regex resource refer to:

• regexr.com
• regex cheatsheet
  
  

About This Blog Application

This blog application mainly shares knowledge of  Linux administration and management. You are welcome to leave a comment for query.

Here is my major git commit log:

commit 57e4f7988a7f2789986833b31c09f155b6230570
Author: hide
Date:   Fri Aug 7 11:04:10 2020 +0000

    updated sitemap

commit 80f6db8b105f079aa262bd8aee848a6e47fbb1b3
Author: hide
Date:   Wed Aug 5 14:58:12 2020 +0000

    1. implemented safe delete action for Post by updating Post model, so it
    could be recovered from database if needed;
    2. fixed tags issue on post_list, only show post's relative tags

commit e1cd24bbdea24e4b820fcce7b2e797d255852835
Author: hide
Date:   Wed Aug 5 12:38:12 2020 +0000

    - fixed URL issue for post_detail, now support utf-8 URI
    - added a confirm-delete modal for Remove button
    - fixed delaying update on ListView by switching back to view.post_list
    - updated a few field in models.py as not required

commit a57b30e9968c57111768aefd1c25f265dc3dbe40
Author: hide
Date:   Mon Aug 3 17:03:42 2020 +0000

    implemented readable url

commit a9f5b3030e4b9e9c2cf0b772b9fb1b5ba6663975
Author: hide
Date:   Mon Aug 3 11:34:17 2020 +0000

    implemented Pagination and sitemap

commit 51b6eca341e41e93b099cb3963702a798d3cc765
Author: hide
Date:   Fri Jul 31 13:43:27 2020 +0000

    1. implemented views tracking for url
commit 785f4f6445d7a620650e5b4aebdb6eb09c27adfa
Author: hide
Date:   Thu Jul 30 19:50:25 2020 +0000

    added a 'Top' button; and updated navbar appearance

commit abac5c57c27f075b44e8b3c44e3d7623d6067e40
Author: hide
Date:   Wed Jul 29 13:12:22 2020 +0000

    updated font for h1,h2,h3,h4 and navbar

commit 0159a610e62d6eadd92408d878f3761136072af4
Author: hide
Date:   Wed Jul 29 11:47:00 2020 +0000

    1. updated tagged() in blog/views.py and post_list.html
    2. implemented autohide navbar when scroll down

commit 6b59e58e09569eb6d1d8092a449568458f0ceacf
Author: hide
Date:   Tue Jul 28 12:43:26 2020 +0000

    updated templates

commit 4953f170201af35b2e3cd570a81799c63e33506b
Author: hide
Date:   Mon Jul 27 16:15:03 2020 +0000

    1. optimize some templates into post_preview.html;
    2. added blog/static/taggit/

commit a5805fde9107cf7260d9efac7153f11a28931095
Author: hide
Date:   Mon Jul 27 12:23:40 2020 +0000

    implemented Tags function

Elliott Wave Theory is an Over-fitting Model which is Useless and Unprofitable

This post reminded me that why Elliott Wave so-called theory is nonsense, because it is an over-fitting model that has little predictive value for the future.

"What is overfitting in trading? Overfitting in trading is the process of designing a trading system that adapts so closely to historical data that it becomes ineffective in the future."

Refer to What is Overfitting in Trading?

Nested list comprehension syntax in Python

Refer to 

• Understanding nested list comprehension syntax in Python
  

Example: 

>>> non_flat = [ [1,2,3], [4,5,6], [7,8] ]
>>> [y for x in non_flat for y in x]
[1, 2, 3, 4, 5, 6, 7, 8]

Bootstrap 4: Delete confirmation modal for list of items

Refer to 

• Bootstrap 4: Delete confirmation modal for list of items
  

The right way to create database for Django - collation error

The right way to create a database

Refer to 

• django-python-collation-error/7083511#7083511
• fix-django-illegal-mix-of-collations
  

When creating a new database, remember to create with the right collate settings:

CREATE DATABASE foo CHARACTER SET utf8 COLLATE utf8_general_ci;

Change MySQL default character set to UTF-8 in my.cnf? 

Error Number: 1267

Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE) for operation '='

Solutions refer to :

• Illegal mix of collations MySQL Error
• Change MySQL default character set to UTF-8 in my.cnf?

config on /etc/my.cnf

[mysqld]
collation-server = utf8_unicode_ci
init-connect='SET NAMES utf8'
character-set-server = utf8