Aws on Micha Kops' Tech Notes

Modeling AWS Structures with PlantUML and AsciiDoc

Tue, 08 Nov 2022 00:00:00 +0100

The AWS shapes are included in the PlantUML stdlib .. simply include them as shown here:

example.puml

@startuml
!include <awslib/AWSCommon>
!include <awslib/Analytics/ManagedStreamingforKafka>
!include <awslib/Database/RDS>
!include <awslib/General/Users>
!include <awslib/General/InternetGateway>

!include <kubernetes/k8s-sprites-labeled-25pct>

skinparam linetype ortho

title "AWS Context Diagram"


package "EKS Kubernetes Cluster" as eks_cluster {
    component "<$pod>\napp1" as pod1
    component "<$pod>\napp2" as pod2
}

ManagedStreamingforKafka(kafka_pod, "Amazon MSK", "Apache Kafka")

RDS(pg_rds, "PostgreSQL", "Sample Schema")


Users(users, "AppUsers","editors, admins")

InternetGateway(igw1, "Customer Gateway", "Customer access to internal services")

users -> igw1
igw1 --> pod1
igw1 --> pod2
pod1 --> pg_rds
pod1 --> kafka_pod
pod2 --> pg_rds
pod2 --> kafka_pod

@enduml

Annotation based Kubernetes and Openshift Manifests for Java Applications with ap4k

Thu, 28 Feb 2019 00:00:00 +0100

Writing our manifest files for Kubernetes / Openshift often forces us to edit xml, json and yml files by hand.

A new library, ap4k allows to specify metadata for these manifest files directly in our Java code using annotations.

In the following short example I am going to demonstrate how to generate manifest files using Maven and ap4k.

Figure 1. ap4k Tutorial

Dependencies

Using Maven we just need to add the following one dependency to our project’s pom.xml

AWS Snippets

Thu, 01 Mar 2018 00:00:00 +0100

AWS Command Line Interface

Installation

$ curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64-2.0.30.zip" -o "awscliv2.zip"
unzip awscliv2.zip
sudo ./aws/install

AWS Documentation

RDS

Export Database Configuration

Export instance configuration

aws rds describe-db-instances --db-instance-identifier arn:aws:rds:eu-central-1:123456789:db:hascode-prd-db --no-paginate

Export parameter group configuration

aws rds describe-db-parameters --db-parameter-group-name PARAM_GROUP_NAME >> param_group_conf.json

Export option group configuration

aws rds describe-option-groups --option-group-name OPT_GROUP_NAME >> option_group_conf.json

Generate Signed URLs with Linux Tools

e.g. for accessing a website behind a CloudFront distribution using a canned policy.

Write the policy file

Postgres Snippets

Mon, 01 Mar 2010 00:00:00 +0100

Administration & Configuration

Connections

Show Max Connections (value and source)

SELECT setting, source, sourcefile, sourceline
FROM pg_settings
WHERE name = 'max_connections';

Set Max Connections

ALTER system SET max_connections = 250;

Kill Connections for a Database

SELECT pg_terminate_backend(pid)
FROM pg_catalog.pg_stat_activity
-- we don't want to kill our own connection
WHERE pid != pg_backend_pid()
-- we don't want to kill connections to other databases
AND datname = 'MYDATABASE'

Show Statement Timeout Settings for All Users

SELECT r.rolname,
       (SELECT unnest(s.setconfig) FROM pg_db_role_setting s WHERE s.setrole = r.oid AND s.setconfig::text LIKE '%statement_timeout%' LIMIT 1) AS statement_timeout
FROM pg_roles r
WHERE r.rolcanlogin
ORDER BY r.rolname;

Python Snippets

Mon, 01 Mar 2010 00:00:00 +0100

Virtual Environments

Create and activate a venv

python -m venv /path/to/new-env (1)
source /path/to/new-env/bin/activate (2)

1	Creates a new virtual environment
2	Activate the new virtual environment

Deactivate venv

deactivate

Save used dependencies to a file

pip freeze > dependencies.txt

Install dependencies from file

pip install -r dependencies.txt

Storing and fetching Credentials from the System Keyring

I am using jaraco/keyring here:

pip install keyring

import keyring

keyring.set_password("system", "db.sample.password", "xoxo")

print(keyring.get_password("system", "db.sample.password"))