Host legacy application in Docker

This is my notes from containerizing a legacy application with Docker compose. We have to run multiple instances of our application because we’re unable to secure additional VMs for this single-VM education environment. The application is target of containerization, because it requires mass reconfiguration (around TCP port) to run multiple instances of the application. We … Read moreHost legacy application in Docker

Virtualization 4 of 4 – Networking

Virtual LAN (VLAN) Although VLAN emerged before virtualization and is not part of virtualization topic. I’d just like to start from here as a refresher. Suppose we have computers from finance department and computers from sales department all connected to a single layer-2 switch. There are at least three problems: 1) too many devices on … Read moreVirtualization 4 of 4 – Networking

Virtualization 3 of 4 – Containers

In broad terms, virtualization of computing resource is about isolation of resources at different levels. We have covered hypervisor-based virtualization in the other post. In this article, we continue to dive into OS level virtualization. Remember again that the gist of virtualization is isolation of resource. To support OS level virtualization, the OS must have … Read moreVirtualization 3 of 4 – Containers

Docker network

Reading notes of “Docker DeepDive” Docker networking is backed by libnetwork, which is an implementation of Container Network Model (CNM), an open-source pluggable architecture designed to provide networking to containers. Libnetwork also provides native service discovery and basic container load balancing solution. Docker networking also involves some drivers that extend the CNM model with specific … Read moreDocker network

Setup WSL2 on Windows 10

This is not for Linux snobs, but rather for those who are stuck with a Windows work laptop, have to deal with Linux on a daily basis, and are not a fan of PuTTY. This posting provides the steps to setup Windows 10 so you get a work environment closer to a Linux one. The … Read moreSetup WSL2 on Windows 10

Docker Stack, Docker Swarm and Docker storage

Reading notes from Docker Deep Dive Docker Stack A stack is a set of related services and infrastructure that gets deployed and managed as a unit. A docker stack file has the same format as Docker Compose file, with the only requirement that the version: key specify a value of 3.0. The other difference between … Read moreDocker Stack, Docker Swarm and Docker storage

Security Assertion Markup Language (SAML)

SAML is an XML-based standard for exchanging authentication and authorization data between IdP (identity provider) and service provider. We can compare SAML with LDAP (as authentication protocol) as both are to provide single-sign-on (SSO) feature. LDAP is considered traditional configuration in on-premise operation for organizations. The configuration can be complex and administrators needs to complete … Read moreSecurity Assertion Markup Language (SAML)

Redhat Firewall configuration: from iptables to firewalld

Tools to manage firewall Packet filter rules in Linux Kernel is managed by an user-space application named iptables in CentOS and RedHat. Since CentOS 7, firewalld is introduced as an alternative to iptables. Firewalld can be installed and executed as a systemd service, and it is supposed to replace iptables. This article describes how to … Read moreRedhat Firewall configuration: from iptables to firewalld