Simple Engineer Notes
154 subscribers
147 photos
2 videos
49 links
Engineering insights from a simple perspective - focusing on DevOps, IaC, OS, automation and solutions without the complexity.

https://www.goncharov.xyz
Download Telegram
πŸ’» dosbox + cp866

About 20+ years ago at school I had a calc project. It was kind of team work + presentation + programming skills. It was turbo pascal & 1000 SLOC. When i was reviewing my photo archive I found that photo & was curious about the sources. yeah.. I had it & was able to start at mac M1 via dosbox. However, I had a problem with code pages.

It was pretty simple to fix

1. Put CYRILLIC.COM from image from http://algmet.simulacrum.me/download.htm to ~/dosbox
2. Add into dosbox config ~/Library/Preferences/DOSBox 0.74-3-3 Preferences
mount d ~/dosbox
d:
CYRILLIC.COM
keyb ru

3. Run /Applications/dosbox.app/Contents/MacOS/DOSBox /.../CALC4.EXE

#oldschool #dos #mac
πŸ‘2πŸ”₯1😁1🀑1
⚑️ Blackout in Spain & Portugal 2025-04-28

At 12:30, the grid lost over 15GW of power(about 60% of its total load).

❓What caused it? There’s no official answer, possible reason:
1. A short circuit triggered by a fire near a high-voltage line
2. This might destabilize a nuclear plant between Bordeaux and Toulouse
3. The domino effect led to a cascade failure & isolated Spain and Portugal from the rest of Europe

πŸ’‘ Why did it take so long to restore? Because the system went down completely, operators couldn’t just flip a switch. They had to perform a black start

πŸ›  What is a black start? you need electricity to make electricity. How it works:
1. Tiny generators(eg diesel-based), kick in first-they don’t need the grid to run
2. They bring online slightly bigger power plants(eg hydro or gas turbines)
3. These medium stations help boot up larger stations like nuclear

Step-by-step, the grid is rebuilt. During that process:
- voltage and frequency must be matched
- the generation and consumption must be aligned
πŸ”₯5πŸ’―1
🌍 Terraform + OTC + windows

Surprisingly it was easy to create, but tricky to get access. It's not really well describe in the docs https://registry.terraform.io/providers/opentelekomcloud/opentelekomcloud/latest/docs/resources/compute_instance_v2#encrypted_password-1

1. Create the instance
resource "opentelekomcloud_compute_instance_v2" "win" {
name = "win"
flavor_id = "s3.large.4"
# Enterprise_Windows-Server_2025_STD_amd64_uefi_latest
image_id = "66b9843e-f662-40b2-a347-da1f99f314da"
key_pair = opentelekomcloud_compute_keypair_v2.pubkey.pub_key_name
...
}
...
output "win_admin_password_encrypted" {
value = opentelekomcloud_compute_instance_v2.win.encrypted_password
sensitive = true
}

2. wait about ~5-10 mins till encrypted_password is reachable
3. Decode the password
echo pass - `terraform output -raw win_admin_password_encrypted | base64 -d | openssl rsautl -decrypt -inkey /path/to/private/key`


Alternative 1:
It's possible to print the password if terraform is able to decrypt
data "opentelekomcloud_compute_instance_v2" "win" {
id = opentelekomcloud_compute_instance_v2.win.id
ssh_private_key_path = "/path/to/private/key"
}

output "win_admin_password" {
value = data.opentelekomcloud_compute_instance_v2.win.password
sensitive = true
}


Alternative 2:
If there is cloud init inside, than it can be customized like that:
resource "opentelekomcloud_compute_instance_v2" "win" {
name = "win"
flavor_id = "s3.large.4"
# Enterprise_Windows-Server_2025_STD_amd64_uefi_latest
image_id = "66b9843e-f662-40b2-a347-da1f99f314da"
user_data = base64encode(<<-EOF
#ps1
$pwdAdmin = ConvertTo-SecureString "versysecurepassword" -AsPlainText -Force
Set-LocalUser -Name Administrator -Password $pwdAdmin -PasswordNeverExpires:$true
EOF
)



#terraform #til #otc #windows
πŸ‘1
πŸ›  Ansible doesn't support python path with spaces

1️⃣ Jenkins job issue
I have jenkins job to test ansible roles. The job was was moved to the jenkins folder with the space & the error appeared:

<127.0.0.1> EXEC /bin/sh -c 'ANSIBLE_ASYNC_DIR=/home/jenkins_slave/.ansible_async/ /home/jenkins_slave/workspace/Ansible Guild/Snapshot/.venv/bin/python3.12 /home/jenkins_slave/...
failed: [localhost] (item=postgresql-instance) => {
"ansible_loop_var": "item",
...
},
"module_stderr": "/bin/sh: /home/jenkins_slave/workspace/Ansible: No such file or directory\n",
"module_stdout": "",
"msg": "MODULE FAILURE\nSee stdout/stderr for the exact error",
"rc": 127
}


I found that it caused by
1. calling community.docker.docker_container https://github.com/ansible-community/molecule-docker/blob/main/src/molecule_docker/playbooks/destroy.yml which executing
2. the python code https://github.com/ansible-collections/community.docker/blob/main/plugins/module_utils/module_container/module.py which called
3. the python code https://github.com/ansible/ansible/blob/devel/lib/ansible/modules/async_wrapper.py

2️⃣ Reproduce
so it wasn't about the molecule. I decided to reproduce it:

1. Prepare the venv
 mkdir "test dir"
cd test\ dir/
export PYTHONPATH=/usr/lib64/python3.6/site-packages
python3.12 -m venv .venv --system-site-packages
. .venv/bin/activate
pip3 install --upgrade pip
pip3 install -r ../example/requirements.txt

2. Run debug
ANSIBLE_KEEP_REMOTE_FILES=1 ansible  -vvvv -m stat -c local -i 'asd,' asd
...
python3 ./AnsiballZ_stat.py explode

3. check internals
 echo PLATFORM; uname; echo FOUND; command -v 'python3.12'; command -v 'python3.11'; command -v 'python3.10'; command -v 'python3.9'; command -v 'python3.8'; command -v 'python3.7'; command -v 'python3.6'; command -v '/usr/bin/python3'; command -v '/usr/libexec/platform-python'; command -v 'python2.7'; command -v '/usr/bin/python'; command -v 'python'; echo ENDFOUND
PLATFORM
Linux
FOUND
/home/username/test dir/.venv/bin/python3.12
/home/username/.pyenv/shims/python3.9
/usr/bin/python3.8
/usr/bin/python3.6
/usr/bin/python3
/usr/libexec/platform-python
/home/ms/lgonchar/test dir/.venv/bin/python
ENDFOUND

the module detected symlink and caused the issue.

4️⃣ What is the source?
1. .venv/lib64/python3.12/site-packages/ansible/executor/interpreter_discovery.py:60
try:
...
shell_bootstrap = "echo PLATFORM; uname; echo FOUND; {0}; echo ENDFOUND".format('; '.join(command_list))

2. .venv/lib64/python3.12/site-packages/ansible/plugins/action/__init__.py
found_interpreters = [interp.strip() for interp in match.groups()[1].splitlines() if interp.startswith('/')]
quoted_interpreters = []
for interpreter in found_interpreters:
if ' ' in interpreter and not (interpreter.startswith('"') or interpreter.startswith("'")):
quoted_interpreters.append('"%s"' % interpreter)
else:
quoted_interpreters.append(interpreter)
found_interpreters = quoted_interpreters

so the idea was to modify the .venv/lib64/python3.12/site-packages/ansible/plugins/action/__init__.py

if ' ' in interpreter:
interpreter = shlex.quote(interpreter)
async_cmd = [interpreter, remote_async_module_path, async_jid, async_limit, remote_module_path]


It fixed the python detection but also there are some other places were _low_level_execute_command is called and much work to do.

5️⃣ Final
1. Rename the jenkins folder without space
2. Propose to use the first interpreter without spaces https://github.com/ansible/ansible/issues/82535#issuecomment-2910076878

#ansible #debug #jenkins
πŸ”₯1
πŸ“„Key notes from systemd@meta speach

https://pretalx.devconf.info/devconf-cz-2025/talk/KNER89/

- systems is used everywhere. So there is special team to manage problems & contribute
- use different name spaces for different services
- minimize diff & stay sync with the upstream
- tests are heavy and not all of then can be executed inside containers
- systemd inside systemd is coming
- dbus will be replaced by varlink

#conf #linux #devconf
πŸ‘2πŸ”₯1
πŸ“„ key notes from diagram as code

https://pretalx.devconf.info/devconf-cz-2025/talk/KDBZQ3/

- if more than 10s are required to read your diagram then simplify it
- in v1 approach there is fundamental issue with consistency of multiple diagrams because it’s like text
- v2 approach is about using code instead of text for diagrams. Like code or scripts

#conf #devconf
πŸ‘1🀑1