reveal.js

What is a container?

Note:
              - feels like a VM
                - we can SSH into it
              - but its not a VM
              - cgroups and namespaces
                - been around since 2008, as c-groups in linux, this paved the path for containers later on
                - cgroups are used to control CPU and Memory
                - namespaces

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<img data-src="./images/vm_vs_container.jpg"></img>
              <br/>
              VM Vs Container

Note:
              - VM: dedicated resource
                Container: shared resources
              - No inconcistency issues
              - Demo container
                - cp -r /usr/bin/ .
                - cp -r /usr/lib/ .
                - cp -r /usr/lib64/ .
                - touch sample.txt
                - pwd
              - I dont think setting up a VM is that easy!
              - examples of container runtimes: firejail, lxc, docker

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Limitations of VM
                - versioning
                - replication
                - upgrades

Note:
              - originally traditional servers, perfect replication not possible, multiple variables
                - os, os version, os deps and versions, application deps and versions
              - probelems
                - versioning: i setup test env today, and setup production tomorrow, there may be inconcistency in the OS level deps, which may cause incompatibility
                - upgrade:
                  - keeping all deps updated is important to avoid security vulns, but it comes at a cost of inconcistency
                  - security upgrades and patching needs to be done across all VMs, in docker only on host OS
                - replication: b/w qa and prod env, local dev, works on my machine, doesnt work in prod, dev work on mac books, prod is centos

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Containers
                - filesystem isolation
                - process isolation
                - device isolation
                - network isolation
                - scaling

Note:
              - now containres, package entire app, incluing the OS level deps, makes it easy to deploy and have concistency in the environemnts

- now:
                - isolation
                  - fs: file:///home/cc firefox demo, iso apps scannnig directories they are not supposed to, like chrome
                  - process: app 1 isnt aware about app b running
                    - d run -it --rm --name nginx nginx:alpine
                    - d exec -it nginx sh
                  - device: GPU
                    - lxc exec steam -- sudo --login --user ubuntu bash
                      - nvidia-smi
                    - lxc exec matlab -- sudo --login --user ubuntu bash
                      - nvidia-smi
                  - network:
                    - d run -it --rm python:3.9.4-alpine3.13 sh
                    - d run -it --rm --network none python:3.9.4-alpine3.13 sh
                    - ping 1.1.1.1
                - scaling: better utilization of resources, resource allocation and sharing

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Kubernetes
                - 0 downtime upgrade <a href="https://nginx-blue-green.codingcoffee.me/" target="_blank">demo</a>
                - maintains state
                - scaling

Note:
              - Production-Grade Container Orchestration Platform
              - Orchestration takes away a lot of operations workload from engg
              - SSL termination
              - Think of k8s as a knowledge base of all the best practicies for deployment of applications built at scale by Google