#+STARTUP: overview
#+TITLE: my scrappy ansible notes
#+AUTHOR: blizzack

* <2023-10-23 Mon> ---------------------------------------------------------

- installing ansible via pip

bash-5.2$ python3 -m pip install --user ansible
Collecting ansible
  Downloading ansible-8.5.0-py3-none-any.whl (47.5 MB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 47.5/47.5 MB 10.5 MB/s eta 0:00:00
Collecting ansible-core~=2.15.5
  Downloading ansible_core-2.15.5-py3-none-any.whl (2.2 MB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 2.2/2.2 MB 11.4 MB/s eta 0:00:00
Collecting resolvelib<1.1.0,>=0.5.3
  Downloading resolvelib-1.0.1-py2.py3-none-any.whl (17 kB)
Collecting cryptography
  Downloading cryptography-41.0.4-cp37-abi3-manylinux_2_28_x86_64.whl (4.4 MB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 4.4/4.4 MB 11.2 MB/s eta 0:00:00
Requirement already satisfied: PyYAML>=5.1 in /usr/lib64/python3.9/site-packages (from ansible-core~=2.15.5->ansible) (6.0)
Requirement already satisfied: packaging in /usr/lib64/python3.9/site-packages (from ansible-core~=2.15.5->ansible) (21.3)
Collecting importlib-resources<5.1,>=5.0
  Downloading importlib_resources-5.0.7-py3-none-any.whl (24 kB)
Requirement already satisfied: jinja2>=3.0.0 in /usr/lib64/python3.9/site-packages (from ansible-core~=2.15.5->ansible) (3.0.3)
Requirement already satisfied: MarkupSafe>=2.0 in /usr/lib64/python3.9/site-packages (from jinja2>=3.0.0->ansible-core~=2.15.5->ansible) (2.0.1)
Requirement already satisfied: cffi>=1.12 in /usr/lib64/python3.9/site-packages (from cryptography->ansible-core~=2.15.5->ansible) (1.15.0)
Requirement already satisfied: pyparsing!=3.0.5,>=2.0.2 in /usr/lib64/python3.9/site-packages (from packaging->ansible-core~=2.15.5->ansible) (2.4.7)
Requirement already satisfied: pycparser in /usr/lib64/python3.9/site-packages (from cffi>=1.12->cryptography->ansible-core~=2.15.5->ansible) (2.21)
Installing collected packages: resolvelib, importlib-resources, cryptography, ansible-core, ansible
  WARNING: The scripts ansible, ansible-config, ansible-connection, ansible-console, ansible-doc, ansible-galaxy, ansible-inventory, ansible-playbook, ansible-pull and ansible-vault are installed in '/home/dpierre/.local/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
  WARNING: The script ansible-community is installed in '/home/dpierre/.local/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
Successfully installed ansible-8.5.0 ansible-core-2.15.5 cryptography-41.0.4 importlib-resources-5.0.7 resolvelib-1.0.1
bash-5.2$ echo $PATH
/usr/local/bin:/usr/bin:/bin:/usr/games:/usr/lib64/libexec/kf5:/usr/lib64/qt5/bin
bash-5.2$ export PATH=$PATH:~/.local/bin
bash-5.2$ echo $PATH
/usr/local/bin:/usr/bin:/bin:/usr/games:/usr/lib64/libexec/kf5:/usr/lib64/qt5/bin:/home/dpierre/.local/bin
bash-5.2$ 
bash-5.2$ 
bash-5.2$ python3 -m pip install --user ansible
Requirement already satisfied: ansible in /home/dpierre/.local/lib/python3.9/site-packages (8.5.0)
Requirement already satisfied: ansible-core~=2.15.5 in /home/dpierre/.local/lib/python3.9/site-packages (from ansible) (2.15.5)
Requirement already satisfied: cryptography in /home/dpierre/.local/lib/python3.9/site-packages (from ansible-core~=2.15.5->ansible) (41.0.4)
Requirement already satisfied: PyYAML>=5.1 in /usr/lib64/python3.9/site-packages (from ansible-core~=2.15.5->ansible) (6.0)
Requirement already satisfied: jinja2>=3.0.0 in /usr/lib64/python3.9/site-packages (from ansible-core~=2.15.5->ansible) (3.0.3)
Requirement already satisfied: resolvelib<1.1.0,>=0.5.3 in /home/dpierre/.local/lib/python3.9/site-packages (from ansible-core~=2.15.5->ansible) (1.0.1)
Requirement already satisfied: importlib-resources<5.1,>=5.0 in /home/dpierre/.local/lib/python3.9/site-packages (from ansible-core~=2.15.5->ansible) (5.0.7)
Requirement already satisfied: packaging in /usr/lib64/python3.9/site-packages (from ansible-core~=2.15.5->ansible) (21.3)
Requirement already satisfied: MarkupSafe>=2.0 in /usr/lib64/python3.9/site-packages (from jinja2>=3.0.0->ansible-core~=2.15.5->ansible) (2.0.1)
Requirement already satisfied: cffi>=1.12 in /usr/lib64/python3.9/site-packages (from cryptography->ansible-core~=2.15.5->ansible) (1.15.0)
Requirement already satisfied: pyparsing!=3.0.5,>=2.0.2 in /usr/lib64/python3.9/site-packages (from packaging->ansible-core~=2.15.5->ansible) (2.4.7)
Requirement already satisfied: pycparser in /usr/lib64/python3.9/site-packages (from cffi>=1.12->cryptography->ansible-core~=2.15.5->ansible) (2.21)
bash-5.2$ ll ~/.local/bin
bash: ll: command not found
bash-5.2$ alias ll='ls -al'
bash-5.2$ ll ~/.local/bin
total 56
drwxr-xr-x 2 dpierre users 4096 Oct 23 12:18 .
drwx------ 5 dpierre users 4096 Oct 23 12:18 ..
-rwxr-xr-x 1 dpierre users  216 Oct 23 12:18 ansible
-rwxr-xr-x 1 dpierre users  236 Oct 23 12:18 ansible-community
-rwxr-xr-x 1 dpierre users  217 Oct 23 12:18 ansible-config
-rwxr-xr-x 1 dpierre users  246 Oct 23 12:18 ansible-connection
-rwxr-xr-x 1 dpierre users  218 Oct 23 12:18 ansible-console
-rwxr-xr-x 1 dpierre users  214 Oct 23 12:18 ansible-doc
-rwxr-xr-x 1 dpierre users  217 Oct 23 12:18 ansible-galaxy
-rwxr-xr-x 1 dpierre users  220 Oct 23 12:18 ansible-inventory
-rwxr-xr-x 1 dpierre users  219 Oct 23 12:18 ansible-playbook
-rwxr-xr-x 1 dpierre users  215 Oct 23 12:18 ansible-pull
-rwxr-xr-x 1 dpierre users 1700 Oct 23 12:18 ansible-test
-rwxr-xr-x 1 dpierre users  216 Oct 23 12:18 ansible-vault

bash-5.2$ ansible --version
ansible [core 2.15.5]
  config file = None
  configured module search path = ['/home/dpierre/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/dpierre/.local/lib/python3.9/site-packages/ansible
  ansible collection location = /home/dpierre/.ansible/collections:/usr/share/ansible/collections
  executable location = /home/dpierre/.local/bin/ansible
  python version = 3.9.18 (main, Sep 15 2023, 12:58:45) [GCC 13.2.0] (/usr/bin/python3)
  jinja version = 3.0.3
  libyaml = True


bash-5.2$ ansible-community --version
Ansible community version 8.5.0


bash-5.2$ python3 -m pip install --user argcomplete
Collecting argcomplete
  Downloading argcomplete-3.1.2-py3-none-any.whl (41 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 41.5/41.5 kB 2.3 MB/s eta 0:00:00
Installing collected packages: argcomplete
Successfully installed argcomplete-3.1.2


bash-5.2$ pip3 list
Package                       Version
----------------------------- ---------
alabaster                     0.7.12
ansible                       8.5.0
ansible-core                  2.15.5
appdirs                       1.4.4
argcomplete                   3.1.2
Babel                         2.10.1
Brotli                        1.1.0
build                         0.10.0
caca                          0.99b20
certifi                       2021.10.8
cffi                          1.15.0
chardet                       4.0.0
charset-normalizer            2.0.10
cryptography                  41.0.4
cupshelpers                   1.0
Cython                        0.29.36
distro                        1.6.0
dnspython                     2.1.0
docutils                      0.17.1
doxypypy                      0.8.8.6
doxyqml                       0.5.1
flit_core                     3.9.0
future                        0.18.2
getmail6                      6.18.13
glad2                         2.0.4
gyp                           0.1
idna                          3.3
imagesize                     1.3.0
importlib-metadata            5.0.0
importlib-resources           5.0.7
include_server                3.4
installer                     0.7.0
Jinja2                        3.0.3
kapidox                       5.111.0
libwebp                       0.0
lxml                          4.9.3
M2Crypto                      0.38.0
Mako                          1.1.6
Markdown                      3.3.4
MarkupSafe                    2.0.1
mercurial                     6.5.2
meson                         1.2.3
netsnmp-python                1.0a1
nftables                      0.1
notify2                       0.3.1
packaging                     21.3
pbr                           5.8.0
Pillow                        8.4.0
pip                           22.2.2
ply                           3.11
pssh                          2.3.5
pycairo                       1.20.1
pycparser                     2.21
pycups                        2.0.1
pycurl                        7.44.1
Pygments                      2.10.0
PyGObject                     3.44.1
pyparsing                     2.4.7
pyproject_hooks               1.0.0
PyQt5                         5.15.2
PyQt5_sip                     4.19.25
pysol-cards                   0.12.0
python-sane                   2.9.1
pytz                          2022.1
pyxdg                         0.27
PyYAML                        6.0
QScintilla                    2.11.6
random2                       1.0.1
requests                      2.26.0
resolvelib                    1.0.1
rpm                           4.18.1
SCons                         4.5.2
setuptools                    65.1.1
setuptools-scm                6.4.2
sip                           4.19.25
six                           1.16.0
snowballstemmer               2.2.0
Sphinx                        4.5.0
sphinxcontrib-applehelp       1.0.2
sphinxcontrib-devhelp         1.0.2
sphinxcontrib-htmlhelp        2.0.0
sphinxcontrib-jsmath          1.0.1
sphinxcontrib-qthelp          1.0.3
sphinxcontrib-serializinghtml 1.1.5
tomli                         1.2.2
tomli_w                       1.0.0
undervolt                     0.3.0
urllib3                       1.26.8
wheel                         0.41.1
zenmap                        7.94
zipp                          3.8.0


bash-5.2$ ll ~/.local/bin
total 72
drwxr-xr-x 2 dpierre users 4096 Oct 23 12:30 .
drwx------ 5 dpierre users 4096 Oct 23 12:18 ..
-rwxr-xr-x 1 dpierre users 4707 Oct 23 12:30 activate-global-python-argcomplete
-rwxr-xr-x 1 dpierre users  216 Oct 23 12:18 ansible
-rwxr-xr-x 1 dpierre users  236 Oct 23 12:18 ansible-community
-rwxr-xr-x 1 dpierre users  217 Oct 23 12:18 ansible-config
-rwxr-xr-x 1 dpierre users  246 Oct 23 12:18 ansible-connection
-rwxr-xr-x 1 dpierre users  218 Oct 23 12:18 ansible-console
-rwxr-xr-x 1 dpierre users  214 Oct 23 12:18 ansible-doc
-rwxr-xr-x 1 dpierre users  217 Oct 23 12:18 ansible-galaxy
-rwxr-xr-x 1 dpierre users  220 Oct 23 12:18 ansible-inventory
-rwxr-xr-x 1 dpierre users  219 Oct 23 12:18 ansible-playbook
-rwxr-xr-x 1 dpierre users  215 Oct 23 12:18 ansible-pull
-rwxr-xr-x 1 dpierre users 1700 Oct 23 12:18 ansible-test
-rwxr-xr-x 1 dpierre users  216 Oct 23 12:18 ansible-vault
-rwxr-xr-x 1 dpierre users 2605 Oct 23 12:30 python-argcomplete-check-easy-install-script
-rwxr-xr-x 1 dpierre users 1993 Oct 23 12:30 register-python-argcomplete


bash-5.2$ acivate-global-python-argcomplete --user
bash: acivate-global-python-argcomplete: command not found
(failed reverse-i-search)`': ll ~/^Cocal/bin
bash-5.2$ echo $PATH
/usr/local/bin:/usr/bin:/bin:/usr/games:/usr/lib64/libexec/kf5:/usr/lib64/qt5/bin:/home/dpierre/.local/bin
bash-5.2$ ~/.local/bin/activate-global-python-argcomplete --user
Argcomplete was installed in the user site local directory. Defaulting to user installation.
Adding shellcode to /home/dpierre/.zshenv...
Added.
Adding shellcode to /home/dpierre/.bash_completion...
Added.
Please restart your shell or source the installed file to activate it.
bash-5.2$ 
bash-5.2$ 
bash-5.2$ ll
total 104
drwx--x--x 18 dpierre users 4096 Oct 23 12:38 .
drwxr-xr-x  5 root    root  4096 Oct  9 13:23 ..
-rw-------  1 dpierre users   63 Oct 23 11:55 .Xauthority
drwxr-xr-x  3 dpierre users 4096 Oct 23 12:26 .ansible
-rw-r--r--  1 dpierre users  165 Oct 23 12:38 .bash_completion
-rw-------  1 dpierre users  403 Oct 22 18:25 .bash_history
drwx------ 20 dpierre users 4096 Oct 23 12:34 .cache
drwxr-xr-x 15 dpierre users 4096 Oct 23 12:38 .config
drwx------  3 dpierre users 4096 Oct 17 14:20 .dbus
drwx------  3 dpierre users 4096 Oct 23 12:23 .emacs.d
-rw-r--r--  1 dpierre users  270 Oct 23 11:55 .gtkrc-2.0
drwxr-xr-x  2 dpierre users 4096 Oct 23 11:55 .hplip
-rw-------  1 dpierre users   20 Oct 17 14:16 .lesshst
drwx------  5 dpierre users 4096 Oct 23 12:18 .local
drwx------  4 dpierre users 4096 Oct 17 14:29 .mozilla
-rw-r--r--  1 dpierre users 3729 Feb  1  2022 .screenrc
-rw-------  1 dpierre users   63 Oct 23 11:55 .serverauth.1719
-rw-r--r--  1 dpierre users  160 Oct 23 12:38 .zshenv
drwxr-xr-x  2 dpierre users 4096 Oct 23 12:34 Desktop
drwxr-xr-x  2 dpierre users 4096 Oct 17 14:20 Documents
drwxr-xr-x  2 dpierre users 4096 Oct 17 14:20 Downloads
drwxr-xr-x  2 dpierre users 4096 Oct 17 14:20 Music
drwxr-xr-x  2 dpierre users 4096 Oct 17 14:20 Pictures
drwxr-xr-x  2 dpierre users 4096 Oct 17 14:20 Public
drwxr-xr-x  2 dpierre users 4096 Oct 17 14:20 Templates
drwxr-xr-x  2 dpierre users 4096 Oct 17 14:20 Videos
bash-5.2$ 


since i installed ansible locally i assume much of my configurations
are local as well. In the docs
https://docs.ansible.com/ansible/latest/installation_guide/intro_configuration.html#getting-the-latest-configuration
it states that one can view the configuration in
'/etc/ansible/ansible.cfg'

bash-5.2$ ansible-config list
...
...
...


bash-5.2$ ansible-config view
ERROR! Invalid or no config file was supplied


after viewing
https://docs.ansible.com/ansible/latest/cli/ansible-config.html

seems i need to create an '~/.ansible.cfg' that will override any
other config files created 'globally'. There is no global one in my
case.

more info on configuration precedence can be found here.
https://docs.ansible.com/ansible/latest/reference_appendices/config.html


bash-5.2$ ansible-config init --disabled -t all > ansible.cfg
bash-5.2$ cp -arv ansible_all.cfg .ansible.cfg
bash-5.2$ chmod 600 .ansible.cfg

to get a list of all configuration options w/ my setup

bash-5.2$ ansible-config list > ansible-config-list.txt


reviewing building our inventory
https://docs.ansible.com/ansible/latest/inventory_guide/intro_inventory.html

bash-5.2$
bash-5.2$
bash-5.2$
bash-5.2$

* <2023-10-24 Tue> ---------------------------------------------------------

decided it would be nice to have another host to play around with so
i dusted off 'bbox' and logged into it from 'boom2'

bash-5.2$ ssh-keygen -t ed25519 -C "bbox test from boom2" -f ~/.ssh/20231024bbox
Generating public/private ed25519 key pair.
Created directory '/home/dpierre/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/dpierre/.ssh/20231024bbox
Your public key has been saved in /home/dpierre/.ssh/20231024bbox.pub
The key fingerprint is:
SHA256:UpDK1R9LlJ30unU6vDGyJ0tDFdc/6dHPMlYHTSQZWIs bbox test from boom2
The key's randomart image is:
+--[ED25519 256]--+
|      .o ..+.+=*=|
|      o.. + +oo=o|
|   . o  .o oE +.+|
|    o  .  o  o +=|
|      . S   o oo*|
|       .   . +++o|
|            =.*o |
|           ..+.= |
|            o+.  |
+----[SHA256]-----+
bash-5.2$ 
bash-5.2$ 
bash-5.2$ ssh-keygen -l -f ~/.ssh/20231024bbox
256 SHA256:UpDK1R9LlJ30unU6vDGyJ0tDFdc/6dHPMlYHTSQZWIs bbox test from boom2 (ED25519)
bash-5.2$ ll ~/.ssh/
total 16
drwx------  2 dpierre users 4096 Oct 24 14:16 .
drwx--x--x 19 dpierre users 4096 Oct 24 14:16 ..
-rw-------  1 dpierre users  464 Oct 24 14:16 20231024bbox
-rw-r--r--  1 dpierre users  102 Oct 24 14:16 20231024bbox.pub



i had a little dilemma as i cannot log into 'bbox' w/out using an ssh
key; so i needed to get my newly created pubkey inserted as line entry
inside of 'dpierre@bbox:~/.ssh/authorized_keys'.

since i can log into 'bbox' from 'boom' i copied the
'~/.ssh/20231024bbox.pub' to a USB key. then copied that file over to
'boom' and from there logged into 'bbox' and appended the line inside
of 'dpierre@bbox:~/.ssh/authorized_keys'.

i was able to test it easily...


bash-5.2$ ssh -i ~/.ssh/20231024bbox dpierre@192.168.0.220
The authenticity of host '192.168.0.220 (192.168.0.220)' can't be established.
ED25519 key fingerprint is SHA256:KIFNv05/0KyoX0hfK8U4ILud0fP+BVeeAhHMlakXumo.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '192.168.0.220' (ED25519) to the list of known hosts.
Enter passphrase for key '/home/dpierre/.ssh/20231024bbox': 
Last login: Tue Oct 24 13:31:18 2023 from 192.168.0.148
Linux 5.15.19.

For those who like this sort of thing, this is the sort of thing they like.
                -- Abraham Lincoln

dpierre@bbox:~$ ll
-bash: ll: command not found
dpierre@bbox:~$ alias ll='ls -al'
dpierre@bbox:~$ ll
...
...
dpierre@bbox:~$ 
logout
Connection to 192.168.0.220 closed.


- edited '~/.ansible.cfg'
  - uncommeted / added the following entry under the [default] entry
      private_key_file=~/.ssh/20231024bbox

  - uncommeted/edited this line from:
      ;inventory=/etc/ansible/hosts

        -to-

      inventory=~/.ansible/hosts

      https://www.educba.com/ansible-hosts-file/

* <2023-10-29 Sun> ---------------------------------------------------------

- created '~/.ansible/hosts' file like so:

    #+begin_src
      [test]
      192.168.0.220

      [dev]
      192.168.0.220
    #+end_src

- i ran the following commands

ansible all --list-hosts
ansible-inventory --list
ansible-inventory --graph

ansible all -m ping
ansible dev -m ping


- the above reference using the inventory file '~/.ansible/hosts' but
  when executing ansible commands we can use any inventory file as
  long as we use the '-i' switch to explicitly point to it. like so:

    ansible all -i /some/path/to/my/inventory_file -m ping

    ansible-playbook -i /some/path/to/my/inventory_file 01-playbook-hello.yml

  - the following resource shows so many different ways to setup your
    inventory file(s).  it shows detailed ways of organizing nodes
    into groups and subgroups, inventory variables, use patterns to
    target different groups of servers when running commands &
    playbooks.
    https://assets.digitalocean.com/books/how-to-manage-remote-servers-with-ansible.pdf


- create a file on a host using ansible
  https://phoenixnap.com/kb/ansible-create-file

- need to learn a lil something about how playbooks are structured
  https://www.digitalocean.com/community/tutorial-series/how-to-write-ansible-playbooks

- created the following playbook

    #+name: ~/ansible-practice/01-playbook-hello.yml
    #+begin_src yaml
      ---
      - hosts: all
	tasks:
	  - name: Print message
	    debug:
	      msg: Hello Ansible World
    #+end_src

* <2023-10-30 Mon> ---------------------------------------------------------

- make sure to setup my path correctly so that the ansible executable
  can be found

bash-5.2$ export PATH=$PATH:~/.local/bin
bash-5.2$ echo $PATH

- test our recently made playbook

  bash-5.2$ cd ~/ansible-practice/
  bash-5.2$ ansible-playbook 01-playbook-hello.yml

- created a playbook that only works locally and simply prints out the
  current directory
  https://www.middlewareinventory.com/blog/run-ansible-playbook-locally/

    #+name: ~/ansible-practice/02-playbook-local-test.yml
    #+begin_src yaml
      ---
      - name: "Playing with Ansible localhost"
        hosts: localhost
        connection: local
        tasks:
          - name: "just execute a ls -lrt command"
            shell: "ls -lrt"
            register: "output"

          - debug: var=output.stdout_lines
    #+end_src

  - some other suggestions to run commands locally

    bash-5.2$ ansible localhost -m ping
    bash-5.2$ ansible localhost -m shell -a "ls -alrt"

    - an interesting way to run a playbook meant for external
      hosts...but locally:

      bash-5.2$ ansible-playbook --connection=local --inventory 127.0.0.1, --limit 127.0.0.1 01-playbook-hello.yml

- seems i dont understand YAML well enuf
  https://docs.ansible.com/ansible/latest/reference_appendices/YAMLSyntax.html

* <2023-11-02 Thu> ---------------------------------------------------------

some definitions of things:

- control node    =  my ansible server
- managed node(s) = target systems

* <2023-11-22 Wed> ---------------------------------------------------------

did a lil research on more resources

https://www.lifewire.com/download-free-books-3482754

https://assets.digitalocean.com/books/how-to-manage-remote-servers-with-ansible.pdf

https://www.digitalocean.com/community/cheatsheets/how-to-use-ansible-cheat-sheet-guide
https://docs.ansible.com/ansible/latest/command_guide/intro_adhoc.html


To execute a command on a node, use the -a option followed by the
command you want to run, in quotes.  some of these don't use a -m
<module_name> bcuz they're using the default 'command' module.  we'll
want to be careful using the 'command' module cuz it DOES NOT SUPPORT
extended shell syntaxes like piping and redirects (although shell
variables will always work).  If your command requires shell-specific
syntax, use the shell module instead.

https://docs.ansible.com/ansible/latest/collections/ansible/builtin/command_module.html

some more examples of an adhoc commands that can be run:


dpierre@boom2:~$ ansible all -a "df -Th"

192.168.0.220 | CHANGED | rc=0 >>
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/root      ext4       98G   17G   77G  18% /
devtmpfs       devtmpfs  3.9G     0  3.9G   0% /dev
tmpfs          tmpfs      32M  1.2M   31M   4% /run
tmpfs          tmpfs     3.9G     0  3.9G   0% /dev/shm
cgroup_root    tmpfs     8.0M     0  8.0M   0% /sys/fs/cgroup
/dev/sda1      ext4       89M   82M   73K 100% /boot

-- or --

we could've run the above like so:

  ansible all -m ansible.builtin.shell -a "df -Th"

  https://docs.ansible.com/ansible/latest/collections/ansible/builtin/shell_module.html


dpierre@boom2:~$ ansible all -a "uptime"

192.168.0.220 | CHANGED | rc=0 >>
 14:00:39 up 5 min,  1 user,  load average: 0.15, 0.05, 0.01


- copying files that are owned by myself
ansible all -m ansible.builtin.copy -a "src=./file.txt dest=~/myfile.txt"

- change file permissions
ansible all -m ansible.builtin.file -a "dest=/var/www/file.txt mode=600 owner=sammy group=sammy" --become -K

- invoking services
ansible all -a "/sbin/reboot" --become -K


interesting... we can use a different ssh key with our ansible
commands if we wish like so:

  ansible all -a "df -Th" --private-key=~/.ssh/some/custom_ssh_key

this is also mentioned in the comments within '~/.ansible.cfg' that we
manufactured on <2023-10-23 Mon> 

grrr...so many options!!  we can add a private key directly to the
inventory file we choose to use as well.  there is a variable called
'ansible_ssh_private_key_file=~/.ssh/some/custom_ssh_key'

this resource below mentions this some more:
https://www.digitalocean.com/community/cheatsheets/how-to-manage-multiple-servers-with-ansible-ad-hoc-commands

we use the '-m' switch on ansible commands to reference a command via
the 'command module' to execute that command on the remote server(s).

ansible all -m ansible.builtin.setup
ansible all -m ansible.builtin.setup -a "gather_subset=min"
ansible all -m ansible.builtin.setup -a " filter=*ipv* "
ansible all -m ansible.builtin.setup > ../bbox-system.json

ansible localhost -m ansible.builtin.setup

https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_vars_facts.html


- to list out the tasks of a playbook:

ansible-playbook 12-playbook-copy-directory.yml --list-tasks

playbook: 12-playbook-copy-directory.yml

  play #1 (all): 12 - Playing with Ansible - copy directories from control to managed node      TAGS: []
    tasks:
      copy entire directory     TAGS: [step1]
      copy directory contents   TAGS: [step2]

- to list out the tags of a playbook:

    ansible-playbook 12-playbook-copy-directory.yml --list-tags

    playbook: 12-playbook-copy-directory.yml

      play #1 (all): 12 - Playing with Ansible - copy directories from control to managed node      TAGS: []
	  TASK TAGS: [step1, step2]

- execute tasks by tag

    ansible-playbook 12-playbook-copy-directory.yml --tags=step2

  - skipping tasks by tag

      ansible-playbook 12-playbook-copy-directory.yml --exclude-tags=step1

  - starting execution at specific task

      ansible-playbook 12-playbook-copy-directory.yml --start-at-task=step4

- limiting targets for execution to a set of workstations
  - many typically playbooks set up their target as 'all' by default,
    and sometimes you want to limit the group or single server that
    should be the target for that setup.  You can use -l (limit) to set
    up the target group or server in that play.
    - REMEMBER... the 'hosts' w/in the playbook must be using a group
      of some kind for this to work...or else you'll receive a message
      like "skipping: no hosts matched"

        ansible-playbook -l dev-stations 12-playbook-copy-directory.yml

* <2023-11-30 Thu> ---------------------------------------------------------

researching 'roles' and how to use them.

the issue i have now is that i made a simple playbook that copies
files on to the host as expected...but i want to change where those
files are placed depending on the host type.  i think roles will help
me w/ this.

https://stackoverflow.com/questions/32101001/ansible-playbooks-vs-roles


https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_reuse_roles.html
- the above URL shows an example of using a conditional on which tasks
  to run on a host depending on the host os.  ansible grabs this info
  by calling 'ansible_facts' (grabbing the 'setup') on the host.

  - i grabbed the setup info on each host like so:

      ansible localhost -m ansible.builtin.setup > ansible_setup_on_control_node.json
      ansible dev -m ansible.builtin.setup > ansible_setup_on_dev_node.json

  - the setup info looks very similar for both in that there's no real
    way to discern a managed from a control host simply by reading the json
    - there are differences in the ip address and machine name but not
      much else

- wtf are 'magic variables' (special variables)
  https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_vars_facts.html#information-about-ansible-magic-variables

  maybe this is my answer to finding something that describes the
  control vs managed node

  ansible docs are not very good at explaining this stuff very well !!!

  https://stackoverflow.com/questions/18839509/where-can-i-get-a-list-of-ansible-pre-defined-variables
  - this is not a bad way of pulling these 'magic variables'

    - these are what i need !!

        ansible -m ansible.builtin.debug -a 'var=hostvars' localhost
	ansible -m ansible.builtin.debug -a 'var=hostvars.localhost' localhost

      - i'll get different values for different hosts w/ these
        variables:

	- via my one managed host i see:

            "inventory_hostname": "192.168.0.220",
            "inventory_hostname_short": "192.168.0.220",

	- via my control host i see:

	    "inventory_hostname": "localhost",
	    "inventory_hostname_short": "localhost"

      - so it appears i could use the above 'magic variables' in a
        conditional statement

- role
  - bash_configs
    - tasks
      - main.yml
      - localhost.yml
      - other_hosts.yml

* <2023-12-04 Mon> ---------------------------------------------------------

- experimented w/ using the 'inventory_hostname' above by using an
  example from here:
  https://docs.ansible.com/ansible/latest/collections/ansible/builtin/debug_module.html

- grrr... ansible documentation from redhat is not really good if you
  want a slight tutorial on how to work w/ roles.  it's great at push
  out facts about 'roles' or other constructs but putting it together
  it a good example is quite terrible IMHO.

- this is a great example of a simple role
  https://github.com/cesarvr/ansible-role-hello-world
  - the inet needs more simple examples like this !!

* <2023-12-05 Tue> ---------------------------------------------------------

- How to Use Ansible Roles to Abstract your Infrastructure Environment
   https://www.digitalocean.com/community/tutorials/how-to-use-ansible-roles-to-abstract-your-infrastructure-environment

- i decided im gonna create my roles directory like so: '~/.ansible/roles/'
  - [X] i need to update 'roles_path' in '~/.ansible.cfg' to point to
    this 'roles' directory
- [X] create 'bash_config' role

- had all sorts of issues w/ including files in roles.

    The vars_files key is a play directive. It defines a list of files to
    read from to load variable data. These files are read and parsed at
    the time the playbook itself is parsed. Just as with including tasks
    and handlers, the path is relative to the file referencing the file.

- this is kind of what i want to do...
  https://serverfault.com/questions/589734/ansible-can-i-use-vars-files-when-some-files-do-not-exist
  https://stackoverflow.com/questions/53253879/ansible-vars-files-vs-include-vars
  https://stackoverflow.com/questions/36134552/use-multiple-var-files-in-ansible-role

* <2023-12-07 Thu> ---------------------------------------------------------

- worked w/ 'var_files' and that did not do what i expected
- playing w/ 'group_vars' directory
  https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_variables.html#id44
  - this seemed to work nicely for me.  i created
    '06-playbook-print-group-vars.yml' as an exmple
  - i had to create the following files inside of '/home/dpierre/.ansible'

    ├── group_vars
    │   └── all
    ├── host_vars
    │   └── localhost

    - with the following guts:

      # /home/dpierre/.ansible/group_vars/all
      prefix_dir: ~/

      # /home/dpierre/.ansible/host_vars/localhost
      prefix_dir: ~/tmp/temp_files/

    - i also added the following at the top '/home/dpierre/.ansible/host'

      # /home/dpierre/.ansible/hosts
      ...
      localhost ansible_connection=local
 

- looking again at this:
  https://www.middlewareinventory.com/blog/run-ansible-playbook-locally/
  - i think i just need to employ one of these strategies for running
    a playbook locally and stop fighting friction
    - i believe i'm more interested in methods 3 and 4
    - another link w/ some examples:
      https://nixzie.com/run-ansible-playbook-locally/#Run_Ansible_Playbook_Locally_Using_Local_Action
- this lil argument on SO states that idiomatic roles in ansible
  should not possess roles:
  https://stackoverflow.com/questions/36134552/use-multiple-var-files-in-ansible-role
  - so...this explains why trying to add different variablse for the
    hosts in roles was painful...its bcuz its in the wrong place

* <2023-12-08 Fri> ---------------------------------------------------------

- continued my tests of copying files and found the correct way is to
  use hosts and/or group vars that can be kept in the playbook or w/
  the 'hosts'/'inventory' file.

- made the correct changes and now copied the files to localhost in
  the correct place

- make copy of ~/.ansible into repo for reference:

    rsync -avzhrP ~/.ansible* ~/repos/ansible_repo/home/

- my next projects will be to do the following on a managed host:
  - [ ] setup/update system files
    - import needed public keys
      - slackware
      - slackbuilds
  - [ ] setup/update network files
  - [ ] setup a firewall
    - probably need to use a 'handler' for this
  - [ ] create/update a user
    - [ ] copy/create needed files in users home directory
    - [ ] copy need ssh keys
      - use ansible vaults
    - [ ] add to sudoers
      - may need to use a template' for this
  - [ ] configure/perform slackpkg updates
  - [ ] run the sbopkg package manager to install a package
    - clamav
  - [ ] perform a system backup


- a slacker created a wiki entry on how to perform slackware
  automation using ansible
  https://docs.slackware.com/howtos:slackware_admin:slackware_automation_using_ansible
  https://gitlab.com/mmlj4/ansible_slackware_bootstrap

- some notes on how to use a 'slackpg module' for ansible
  https://docs.ansible.com/ansible/latest/collections/community/general/slackpkg_module.html

- the difference between using 'ansible.builtin.shell' vs
  'ansible.builtin.command'
  https://stackoverflow.com/questions/56663332/difference-between-shell-and-command-in-ansible

* <2023-12-12 Tue> ---------------------------------------------------------

today i learned that ansible makes it a lil difficult to copy/move
files around on the controller node.  they make it very apparent that
ansible is for contolling managed nodes not necessarily controlling
the control node.

* <2023-12-13 Wed> ---------------------------------------------------------

looking at examples to update a file on a managed host

these examples use the 'lineinfile' module
https://www.middlewareinventory.com/blog/ansible-update-etc-hosts-file-across-all-hosts/
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/lineinfile_module.html

- regex syntax for python
  https://docs.python.org/3/library/re.html
- an online python regex syntax checker
  https://pythex.org/

* <2023-12-14 Thu> ---------------------------------------------------------

copy 'rc.firewall' from bbox to boom2:

rsync --progress -avzhr --delete -e 'ssh -i ~/.ssh/20231024bbox' dpierre@192.168.0.220:/etc/rc.d/rc.firewall ~/.ansible/roles/new_host/files/

https://chmod-calculator.com/

* <2023-12-15 Fri> ---------------------------------------------------------

lol..learned of a lil abnormality w/ ansible today.  while testing
replacing contents of a file w/ the 'ansible.builtin.replace' module
it was just not working as i expected.  it seemed that the task
completed ok but no changes took place.  i was testing on a particular
task w/in a playbook.  i was calling the task like so:

#+begin_example
  ansible-playbook 11-playbook-herd-new-host.yml -b -K --tags=slackpkg_blacklist

  BECOME password: 

  PLAY [11 - custom ansible - herd new host] ********************************************

  TASK [Gathering Facts] ****************************************************************
  ok: [192.168.0.220]

  PLAY RECAP ****************************************************************************
  192.168.0.220              : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
#+end_example


the following looks okay...but you really need to look at the above
closely.  i called the 'slackpkg_blacklist' task to be run but the
above output does not state that the task has run.....grrr!!

to debug i had to move the separate task into its own playbook and the
error showed up like so:

#+begin_example
  $ ansible-playbook system/12-replace-text.yml -b -K 
  BECOME password: 

  PLAY [12 - custom ansible - replace text] ***********************************************

  TASK [Gathering Facts] ******************************************************************
  ok: [192.168.0.220]

  TASK [update slackpg blacklist] *********************************************************
  fatal: [192.168.0.220]: FAILED! => {"changed": false, "msg": "Unsupported parameters for (ansible.builtin.replace) module: tags. Supported parameters include: after, attributes, backup, before, encoding, group, mode, owner, path, regexp, replace, selevel, serole, setype, seuser, unsafe_writes, validate (attr, dest, destfile, name)."}

  PLAY RECAP ******************************************************************************
  192.168.0.220              : ok=1    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0  
#+end_example

when i looked closer at my playbook the 'tags:' directive was indented
too much and ansible complained w/ the running playbook.  which is
nice!  but... it did not complain when the task was called directly as
part of a playbook w/ many tasks.

  #+name: BAD EXAMPLE !!!!
  #+begin_example
  - name: update slackpg blacklist
    ansible.builtin.replace:
      path: "{{ backup_etc_dir }}/blacklist-list"
      regexp: '#kernel'
      replace: 'kernel'
      backup: yes
      tags: ['slackpkg_blacklist']
  #+end_example

  #+name: GOOD EXAMPLE !!!!
  #+begin_example
  - name: update slackpg blacklist
    ansible.builtin.replace:
      path: "{{ backup_etc_dir }}/blacklist-list"
      regexp: '#kernel'
      replace: 'kernel'
      backup: yes
    tags: ['slackpkg_blacklist']
  #+end_example

another crazy thing i noticed w/ the first example output above was
that i purposed placed errors in the task to see if i'd get an error
and still no feedback from ansible that anything went wrong.

the lesson learned here: 
- looking at the CLI for awhile can make anyone skip over text on the
  screen.  when calling a task explicitly from a playbook you'll want
  to make sure that task is explictly listed in the output !!!!

** python backtrace

i thought i was gonna need to use pythons regex backtrace construct
but realized i did not need it.  the following are decent resources on
backtrace.

https://www.howtouselinux.com/post/modify-files-with-ansible-lineinfile-replace-and-blockinfile
https://www.programiz.com/python-programming/regex
https://www.pythontutorial.net/python-regex/python-regex-backreferences/

ansible replace examples:
- https://www.linuxtechi.com/replace-strings-lines-with-ansible/

* <2023-12-16 Sat> ---------------------------------------------------------

just pointing out another case of weirdness that occured as a result
of the 'command' vs. 'shell' in a playbook.

this is an example of the playbook tested:

  #+name: using command module
  #+begin_example
  tasks:
    - name: check if user exists
      ansible.builtin.command: id {{ username }}
      register: user_check
      ignore_errors: true

    - name: display user information
      ansible.builtin.debug:
        msg: user '{{ username }}' exists !
      when: user_check.rc == 0

    - name: display error message if user does not exist
      ansible.builtin.debug:
        msg: user '{{ username }}' does not exist !
      when: user_check.rc != 0
  #+end_example

  #+name: using shell module
  #+begin_example
  tasks:
    - name: check if user exists
      ansible.builtin.shell: id {{ username }}
      register: user_check
      ignore_errors: true

    - name: display user information
      ansible.builtin.debug:
        msg: user '{{ username }}' exists !
      when: user_check.rc == 0

    - name: display error message if user does not exist
      ansible.builtin.debug:
        msg: user '{{ username }}' does not exist !
      when: user_check.rc != 0
  #+end_example

for the ignored test that failed i noticed that the "cmd" object
from the command module returns an array, like so:

  #+name: shell module result
  #+begin_example
    ...
    ...
    TASK [check if user exists] ************************************************************
    fatal: [192.168.0.220]: FAILED! => {"changed": true, "cmd": ["id", "testuser1"], "delta": "0:00:00.011568", "end": "2023-12-17 09:04:06.919370", "msg": "non-zero return code", "rc": 1, "start": "2023-12-17 09:04:06.907802", "stderr": "id: ‘testuser1’: no such user", "stderr_lines": ["id: ‘testuser1’: no such user"], "stdout": "", "stdout_lines": []}
    ...ignoring
    ...
    ...
  #+end_example

while the same object under the shell command returns a string, like so:

  #+name: shell module result
  #+begin_example
    ...
    ...
    TASK [check if user exists] ************************************************************
    fatal: [192.168.0.220]: FAILED! => {"changed": true, "cmd": "id testuser1", "delta": "0:00:00.025297", "end": "2023-12-17 08:08:40.530399", "msg": "non-zero return code", "rc": 1, "start": "2023-12-17 08:08:40.505102", "stderr": "id: ‘testuser1’: no such user", "stderr_lines": ["id: ‘testuser1’: no such user"], "stdout": "", "stdout_lines": []}
    ...ignoring
    ...
    ...
  #+end_example

just documenting this fact here cuz i have a feeling this weirdness
will bite me in the ass someday.

* <2023-12-19 Tue> ---------------------------------------------------------

- slackpkg module

  been looking at the slackpkg module
  https://docs.ansible.com/ansible/latest/collections/community/general/slackpkg_module.html

  i was initially wondering how a host receives the correct updates.
  but then i realized that each host has their own configuration that
  should be setup.

  - this is the source code for the slackpkg module
    https://github.com/ansible-collections/community.general/blob/main/plugins/modules/slackpkg.py

- slackbuilds module

  there does not seem to be a module for this since it is considered
  'unofficial'

- interesting i see an example of using a template w/in a template here:
  https://medium.com/@chandrapal/managing-linux-users-ssh-keys-using-ansible-39ee2fc24c16

  - i've seen references online that say this does not work well.
    will need to test this

* <2023-12-20 Wed> ---------------------------------------------------------

- learned a bit about ansible.builtin.fetch
  - copied files from a managed host(s) to the controller
- started working on playbooks to invoke an sbopkg rsync on a host
  - had to perform a bunch of bash trix to get what i want
    - cut command
      https://stackoverflow.com/questions/19482123/extract-part-of-a-string-using-bash-cut-split
      https://stackoverflow.com/questions/6594085/remove-first-character-of-a-string-in-bash
      https://www.geeksforgeeks.org/remove-last-character-from-string-in-linux/
    - tr command
      https://unix.stackexchange.com/questions/9647/how-can-i-find-and-replace-with-a-new-line
      https://stackoverflow.com/questions/19345872/how-to-remove-a-newline-from-a-string-in-bash
      https://www.delftstack.com/howto/linux/use-tr-command-in-linux-bash/
    - sed command
      https://unix.stackexchange.com/questions/144298/delete-the-last-character-of-a-string-using-string-manipulation-in-shell-script

* references
2023-12-16 -- the following is a lists of ansible related URLs compiled so far.

http://mywiki.wooledge.org/BashFAQ/088
https://assets.digitalocean.com/books/how-to-manage-remote-servers-with-ansible.pdf
https://chmod-calculator.com/
https://cyb.org.uk/2021/05/03/bash-productivity.html
https://docs.ansible.com/ansible-core/2.15/reference_appendices/interpreter_discovery.html
https://docs.ansible.com/ansible/2.7/user_guide/playbooks_variables.html#variable-precedence-where-should-i-put-a-variable
https://docs.ansible.com/ansible/2.9/user_guide/playbooks_reuse.html
https://docs.ansible.com/ansible/2.9/user_guide/playbooks_reuse_includes.html#including-and-importing-task-files
https://docs.ansible.com/ansible/latest/cli/ansible-config.html
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/command_module.html
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/copy_module.html
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/debug_module.html
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/file_module.html
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/import_playbook_module.html
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/lineinfile_module.html
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/reboot_module.html
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/replace_module.html
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/shell_module.html
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/stat_module.html
https://docs.ansible.com/ansible/latest/collections/community/general/shutdown_module.html
https://docs.ansible.com/ansible/latest/collections/community/general/slackpkg_module.html
https://docs.ansible.com/ansible/latest/command_guide/intro_adhoc.html
https://docs.ansible.com/ansible/latest/installation_guide/intro_configuration.html#getting-the-latest-configuration
https://docs.ansible.com/ansible/latest/inventory/implicit_localhost.html
https://docs.ansible.com/ansible/latest/inventory_guide/connection_details.html
https://docs.ansible.com/ansible/latest/inventory_guide/intro_inventory.html
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_conditionals.html
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_delegation.html
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_delegation.html#delegating-facts
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_privilege_escalation.html
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_reuse_roles.html
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_variables.html#id44
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_variables.html#registering-variables
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_vars_facts.html
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_vars_facts.html#information-about-ansible-magic-variables
https://docs.ansible.com/ansible/latest/plugins/become.html
https://docs.ansible.com/ansible/latest/reference_appendices/YAMLSyntax.html
https://docs.ansible.com/ansible/latest/reference_appendices/config.html
https://docs.ansible.com/ansible/latest/reference_appendices/faq.html#how-do-i-handle-different-machines-needing-different-user-accounts-or-ports-to-log-in-with
https://docs.python.org/3/library/re.html
https://docs.slackware.com/howtos:slackware_admin:slackware_automation_using_ansible
https://github.com/cesarvr/ansible-role-hello-world
https://gitlab.com/mmlj4/ansible_slackware_bootstrap
https://nixzie.com/run-ansible-playbook-locally/#Run_Ansible_Playbook_Locally_Using_Local_Action
https://phoenixnap.com/kb/ansible-check-if-file-exists
https://phoenixnap.com/kb/ansible-create-file
https://pythex.org/
https://serverfault.com/questions/589734/ansible-can-i-use-vars-files-when-some-files-do-not-exist
https://stackoverflow.com/questions/18839509/where-can-i-get-a-list-of-ansible-pre-defined-variables
https://stackoverflow.com/questions/24162996/how-to-move-rename-a-file-using-an-ansible-task-on-a-remote-system
https://stackoverflow.com/questions/32101001/ansible-playbooks-vs-roles
https://stackoverflow.com/questions/36134552/use-multiple-var-files-in-ansible-role
https://stackoverflow.com/questions/53253879/ansible-vars-files-vs-include-vars
https://stackoverflow.com/questions/56663332/difference-between-shell-and-command-in-ansible
https://www.digitalocean.com/community/cheatsheets/how-to-manage-multiple-servers-with-ansible-ad-hoc-commands
https://www.digitalocean.com/community/cheatsheets/how-to-use-ansible-cheat-sheet-guide
https://www.digitalocean.com/community/tutorial-series/how-to-write-ansible-playbooks
https://www.digitalocean.com/community/tutorials/how-to-use-ansible-roles-to-abstract-your-infrastructure-environment
https://www.educba.com/ansible-hosts-file/
https://www.freekb.net/Article?id=2395
https://www.freekb.net/Article?id=3078
https://www.freekb.net/Article?id=573
https://www.freekb.net/Article?id=759
https://www.howtouselinux.com/post/ansible-copy-module-examples-to-copy-file-to-remote-server
https://www.howtouselinux.com/post/modify-files-with-ansible-lineinfile-replace-and-blockinfile
https://www.lifewire.com/download-free-books-3482754
https://www.linuxtechi.com/replace-strings-lines-with-ansible/
https://www.middlewareinventory.com/blog/ansible-update-etc-hosts-file-across-all-hosts/
https://www.middlewareinventory.com/blog/run-ansible-playbook-locally/
https://www.programiz.com/python-programming/regex
https://www.pythontutorial.net/python-regex/python-regex-backreferences/