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Work Learnings Journal

Work Learnings Journal#

Kubernetes#

  • initContainers (for DaemonSet) - step by step short lived containers, can be used to fixing privileges and setup tasks

  • Kubernetes hostPath ownership are set based on kubelet’s

  • Kubernetes pod logs are stored under /var/log/containers/<pod-name>*<container-id>/*.log (by container runtime)

Linux#

  • list users : /etc/passwd

  • list groups : /etc/group

  • members of group : lid <group-name>

  • owning directory (recursively) chown -R <uid>:<gid> <dir-path>

Go#

  • go mod init <current-module-name> - initializing module for a new app/project

  • go get <dep-name> - install dependencies manually

  • Makefile general target structure

    target : dependency1 dependency2
recipe-command1
recipe-command2

  • Makefile forcefully run without checking dependency build

    .PHONY all: clean build coverage run

    it does not matter if any of the above dependencies are unsatisfied/failed, the whole command will still forcefully be executed

TODOs#

  • Linux Services - sigterm, sigkill

  • AWS - ECS - EC2 (setup), ECS Fargate, ELB, VPC

  • k8s - resource limits vs requests

  • go - build flags (and commented tags etc.), cgo, select, channels concurrency etc.

  • docker - host specific builds, golang-crossbuild

  • python - pipenv, venv

  • OAuth2

  • TLS, mTLS

  • HTTP2, gRPC

Yearly Learning Journal#

2024#

  • TLS

2023#

  • AWS Kinesis Firehose - buffering, processor lambda (lambda buffering), output, intput (kinesis data streams, direct put), failure etc.

  • AWS Cloudformation - custom event, constants, conditions, roles, resources, output, parameters, custom lambda (init processing)

  • AWS S3 events - triggering Lambdas

  • Lambda - cloudwatch loggroup, logstream, event, timeout, cost calc, cold-start and lambda (container) level caching.

  • Eventbridge rules and schedules

  • AWS VPC and Subnets

  • AWS Secrets Manager

  • Linux packages - deb, rpm

  • Oauth2

  • AWS ECS (EC2) - cluster bootstrapping (joining), task-def, service, task, daemon, execution role, volumes and mounts

  • AWS EFS

  • Docker - inspects contents, download files from containers, live debugging and inspection

  • Wrapping executor application with piping STDOUT output and taking input

  • Go - Cobra, flag, options etc.

2022#

  • Kubernetes (kubectl), Daemonset, ConfigMap, Service, Deployment, ServiceAccount, ClusterRole, ClusterRoleBindings

  • Kubernetes Operators (pattern), Go Operator SDK

  • Go, Go string templates

  • Helm charts, Helm templates, Helm repos

  • Kubectx

  • OTel protocol, SDK - logs, metrics

  • OTel collector - receivers (otlp, filelog), exporters (otlp, logging, prometheus), processors (batch, resourcedetection, attribute), extensions

  • OpAMP protocol, SDK - client, server, deployment patterns

  • Elastic Filebeat

2021#

  • Java Agents, Java Instrumentation, Java Bytecode Injection

  • Java Vertx framework internals

  • Java remote debugging, conditional breakpoints, thread debugging

  • Angular, RxJS, Typescript, Jest

2020#

  • React, Redux

2019#

  • Spring Boot, Spring Batch, Spring-Kafka, Spring Data JPA, Spring Data JDBC, Kafka Consumers

  • Apache Camel (pipelines) with Kafka, batch etc.

  • Oracle, MS SQL Server, Stored Procedures

  • Apache Livy

  • Maven

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