The Docker Container Ecosystem 101 @ Docker Bangalore Meetup

June 19, 2021

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The Docker & Container Ecosystem 101

Did you panic when Kubernetes announced the deprecation of Docker runtime support? Are you new to Docker and containerization, or have you gotten lost in all of the terminologies? Attend this session to conquer your fear with knowledge, and breathe a sigh of relief.

View Slides Here

Speakers

Melissa McKay

    Melissa McKay

    Melissa is a long-time developer/software engineer turned international speaker and is currently a Developer Advocate on the JFrog Developer relations team, sharing in the mission to improve the developer experience with DevOps methodologies. Her background and experience as a software engineer span a slew of languages, technologies, and tools used in the development and operation of enterprise products and services. She is a mom, Java Champion, Docker Captain, co-author of the upcoming book DevOps Tools for Java Developers, a huge fan of UNconferences, and is always on the lookout for ways to grow and learn. She has spoken at Kubecon, DockerCon, CodeOne, JFokus, Java Dev Day Mexico, the Great International Developer Summit, and is part of the JCrete and JAlba UNconference teams. Given her passion for teaching, sharing, and inspiring fellow practitioners, you are likely to cross paths with her in the conference circuit — both online and off!

    Video Transcript

    is a developer advocate
    at jfrog she’s a mom she’s a doctor
    cabin
    a java champion and co-author author of
    an upcoming book
    devops tools for java developers
    melissa’s the longtime
    developer turned international speaker
    who will be sharing
    today on the docker and container
    ecosystem 101
    a presentation that she actually shared
    at dockercon this year so without any
    further ado we want to welcome melissa
    hey everyone hey i’m super excited to be
    here
    um really happy to be you know it is i
    think it’s
    12 and a half hour difference or
    something like that it’s actually
    9 45 here right now i’m located in
    denver colorado
    um it’s been really hot here the last
    few days um
    but other than that nothing to complain
    about uh
    i am excited to talk to you about
    containers today
    the docker and container ecosystem to be
    uh specific uh we’re gonna have a new
    batch of developers new to containers
    and to docker every year
    and my personal introduction was sink or
    swim i found myself
    wading through a bunch of new
    terminology i didn’t understand
    and i discovered quite a few stumbling
    blocks that slowed me down
    and not to mention suffering some of the
    consequences of trial and error
    so my goal for you for this talk um the
    first one of today
    is to have a good foundation before you
    jump into the deep end of containers
    we’ve got a lot of container talks
    tonight
    and sometimes we forget that there may
    be some folks in our audience that are
    brand new to this
    and need a little background i could
    have really used a session like this to
    quickly get me up to speed
    on understanding the terminology the
    different components of the big picture
    and clear up any silly misunderstandings
    of overloaded terms
    like container or do we actually store
    containers
    in container registries that kind of
    thing
    this is our agenda today as ari said i
    did
    present this talk at dockercon and it
    was one of the
    the introductory talks so i hope that
    you can get a lot out of this today
    um right now i’ll just uh already
    introduced me already so i’m gonna
    briefly go through a slide there so you
    have my twitter handle and all of that
    business and then we’ll move on to a
    discussion of one
    of why one might want to get comfortable
    with containers right now
    the history lesson is the heaviest
    portion of this talk so make sure you’re
    in a comfortable spot
    get comfortable in your chair where you
    can absorb this info because it’s going
    to come at you pretty fast
    i’ll give a brief explanation of the
    docker ecosystem some of this 101
    terminology
    around containers and then i’ll finish
    off with a few resources
    for you to go and learn more
    ari already introduced to me thank you
    very much for that beautiful
    background i have been in the industry
    for over 20 years
    have been a developer at various levels
    and a year and a half ago joined jfrog
    as a developer advocate i am a java
    champion and a docker captain
    and you can find me at twitter on
    twitter at melissa j mckay
    all right so let’s get started my
    introduction to docker was
    by way of a project that was developed
    by a third-party contractor
    so in my case this wasn’t a decision
    made by our team at the time
    the first thing that i saw when i was
    ramping myself up on the code base where
    were those docker commands in the readme
    file and a file named
    dockerfile in the root of the project
    i’m always up for learning something new
    so i was intrigued what is this docker
    thing
    this particular project that introduced
    me to docker was already designed
    code was already written and functional
    so in this case the best thing for me to
    do was just to dive in and figure out
    how to set it up
    how to build it and deploy it as it was
    this strategy
    has always worked pretty well for me
    when ramping up on any project
    especially when it involves a new tech
    stack or framework
    follow those instructions the best you
    can if you have them we were lucky in
    this case
    to get it up and running make note of
    any difficulties or questions that come
    up
    adjust the instructions if necessary and
    then go back through again to understand
    how all of those pieces fit together
    this is something that you would do
    repeatedly at the beginning of a project
    right away i had so many questions like
    these questions here
    but there was nothing uh initially
    stopping me from moving forward
    i learned best by doing so my first step
    was to download docker desktop to try
    this thing out
    before we get into those darker details
    specifically let’s ask the most
    important question
    why would we or should we use containers
    i don’t know why docker was chosen for
    the product
    project that i was tackling at the time
    i was not involved in those initial
    discussions
    but as i worked with it in setting up
    our development environments and our ci
    cd pipelines
    i saw several advantages
    if you’re doing the same and you’re
    thinking of wrapping your applications
    in containers and going cloud native
    just take a moment to consider the
    problem specific to your project that
    you’d like to solve
    put these down in writing somewhere i
    see so much documentation out there that
    goes into depth on how to do something
    without explaining anywhere why so let’s
    go through this list
    um the first one here is kind of a joke
    really you’re using java 11. well java
    11 was released in september of 2019
    java 16 just came out recently but i
    know
    so many projects that are still back on
    java 8 for various reasons
    i know it’s frustrating to deploy a nice
    new java 11 application
    to a prod machine that only has java 8
    installed
    that’s just one example of you know a
    language specific problem obviously
    contain you know applications that are
    containerized are not all going to be in
    java i’m just pulling from
    from my experience and my background
    here
    the second item here i love my macbook
    my workspace workstation is my macbook
    um i was introduced to mac um i don’t
    know maybe the
    the third position i was in or the third
    team i was on and i haven’t gone back
    since i
    i love it um but how many of you have
    worked in code that has a bunch of if
    statements in it
    around what os you might have i had
    co-workers that were running on windows
    i’m sure there are some legitimate
    reasons for this um
    but i’m remembering scars from the
    browser wars the web browser wars
    but i actually had a situation once
    where unit tests i ran
    failed because i was on a mac instead of
    windows
    there were some other issues there
    multiple problems there to address
    one was how it was dealing with the file
    system but it
    is nice to be able to have the option to
    run unit tests
    in a container without having to worry
    about every possible os
    the third item here there’s a bug in
    production
    the first thing you do as a developer is
    to reproduce the problem
    but that’s difficult when you’re already
    developing the latest and greatest and
    you’ve made changes to your environment
    that are not backward compatible
    consistency and build reproducibility is
    key when you’re chasing those bugs
    number four it works on my machine
    only on my machine that’s related to
    number two
    again consistency in software versions
    and libraries will make your life
    so much less complicated number five we
    just hired three new developers
    this has happened various times in my
    career where a new team is is started up
    or
    new members of the team have joined that
    consistency that you get from step four
    will make onboarding those team members
    so much faster number six
    my service is super popular this is a
    good problem to have
    you’ve put your service out there in the
    cloud and now it’s getting
    hit with a ton of traffic one of the
    biggest reasons for moving to modularity
    and to containers
    is utilizing the strategies of cloud
    native deployments to quickly scale
    that application as you need as load
    increases
    now you might be asking right now um
    don’t don’t virtual machines solve this
    problem for us
    they have isolated environments it
    should be you know just fine
    but the problem with vms vms have their
    advantages
    but they are not as lightweight as
    containers vms contain
    an entire copy of the os so it’s not as
    lightweight
    as a container which actually shares the
    os of its host with
    other containers
    even if you’re not using containers in
    production today there
    are other scenarios worth considering
    the use of containers in your
    development pipeline
    those dev environments don’t suffer from
    the disappointing
    disappointment of spending that entire
    day debugging a problem that you find
    out happens only on your machine
    the test environment having that ability
    to easily launch
    other external services like databases
    that type of thing
    being able to improve your test
    automation that’s an advantage
    and then of course production um you may
    have a problem with
    securing dedicated resources uh
    i know that i was in a situation where
    uh getting a new server set up in
    production involved quite a few
    it tickets and a lot of time you don’t
    have to wait
    for custom provisioning or worry as much
    about inconsistency
    when you’re being when you’re able to
    deploy with containers
    now i want to get into that history that
    i referred to earlier
    it’s really easy to skip this part when
    you’re eager to get started
    but i recommend going through this
    exercise with any new framework or
    technology that you want to start using
    this will be quite a bit of info but
    bear with me because it’s worth it
    understanding how we got here and where
    the tool you’re about to commit to for
    your project
    where it came from can help you avoid
    some nasty pitfalls and help you use
    that tool in the most effective way
    you know that popular cognitive bias
    if all you have is a hammer everything
    looks like a nail
    this is also applicable here containers
    are useful
    but aren’t intended to solve everything
    yet anyway
    all right in the 1960s and 70s computing
    resources were a lot more limited
    than today computers were commonly
    dedicated for long periods of time to a
    single task for a single user
    of course these limitations resulted in
    plenty of bottlenecks and just general
    inefficiency
    efforts were started to develop a method
    of sharing resources without getting in
    each other’s way or having one person
    inadvertently cause the entire system to
    crash for all of its users
    both hardware and software that advanced
    virtualization technology started to
    trickle in
    uh one development in software was
    charut which is where we’ll begin
    in 1979 during the development of this
    seventh edition of unix
    true was developed and then later added
    to the berkeley software
    distribution bsd in 1982.
    this system command allowed for the
    ability to change the apparent root
    directory of a process
    and its children which results in a
    limited view of the file system in order
    to provide
    an environment for testing a different
    distribution for example
    to root was a move in the direction of
    providing the isolation required from us
    today and several years
    later in 2000 freebsd expanded that
    concept and introduced the more
    sophisticated jail command
    and utility in freebsd 4.0 release
    its features later which were later
    improved in 5.1 and the 7.2 releases
    those features helped to further isolate
    file systems
    users and networks and also included the
    ability to assign an ip address to each
    jail
    in 2004 solaris containers and zones
    brought us ahead even further
    by giving an application full user
    process and file system space
    and access to system hardware google
    jumped in with their process containers
    in 2006
    those were later renamed to c groups
    which centered around isolating and
    limiting the resource usage of a process
    in 2008 c groups were merged into the
    linux kernel
    which along with linux namespaces led to
    ibm’s development of linux containers
    lxc you may have heard of those
    now things get even more interesting
    docker was open source in 2013
    and that same year google open sourced
    their let me contain that for you
    project
    which provided applications the ability
    to create and manage their own
    sub containers and from here we saw the
    use of containers
    explode docker containers specifically
    initially docker used galaxy as its
    default execution environment but in
    2014
    docker chose to swap out their use of
    the lxc toolset
    for launching containers with lib
    container which is a native solution
    written
    in go that was something new that i i
    learned i didn’t realize that docker was
    written and go
    soon after the uh let me contain that
    for you project ceased active
    development
    uh with the intention of joining forces
    and migrating the core concepts of that
    project into docker’s lib container
    a lot more stuff happened but before we
    leave
    this i want to point out something
    specific that concerns java applications
    in july of 2011 javas 7
    was released and java 8 was released in
    march of 2014.
    given the development going on in
    containerization at the same time
    it shouldn’t come as a huge surprise
    that older versions of java are not
    fully container aware
    except it is a surprise if you don’t
    know this and you wrap your java 8
    application
    only to suffer from out-of-memory killer
    activity
    the reason for this is that the
    mechanisms the jvm
    used in these older versions to retrieve
    the resources available
    come from the actual host machine and
    not the c group limits that you would
    expect
    although possible with later java 8
    updates i believe it’s 121
    um is is the best you can get for
    java 8. uh it’s recommended to get to
    java 11
    in order to get that version that is
    fully container aware
    all right there’s a lot more that
    happened during this period of time i’m
    intentionally going to skip over some of
    those details in order to get to a
    specific event in 2015.
    this event is really important to know
    about because it’ll give you some
    insight into some of the activity and
    motivations behind shifts
    in the market especially concerning
    docker on june 22
    2015 the establishment of the open
    container initiative
    oci was announced this is an
    organization under the linux foundation
    with the goal of creating open standards
    for container runtimes and image
    specification
    docker is a heavy contributor but in
    their announcement of this new
    organization it was said that over
    20 organizations were involved in this
    um
    i’m would read that list to you
    just so that you can fully comprehend
    the big how big of a deal
    that was these are a lot of companies a
    lot of organizations involved
    it containerization has evolved to such
    an extent that this number of
    organizations wanted to work towards
    some common ground for the benefit of
    all
    the oci accomplished some big things
    um they had in in june 2015
    um you know when they were established
    they had the oci runtime specification
    the oci image specification the oci
    distribution specification
    and in july 2017 uh the runtime and the
    image specs were released as
    version 1.0 on may 4th 2021 the
    distribution spec
    was released again version 1.0
    docker had a lot to do with these
    specifications and i’ll talk to you more
    about what those contributions were in a
    minute
    one month after the oci was established
    the cloud native computing foundation or
    cncf was established
    the cncf does a lot there’s a ton of
    projects there that are either
    incubating or graduated under its
    umbrella
    there are a few activities there that
    you need to know about for
    our purposes along with
    the developments in the container
    ecosystem orchestration was also in
    rapid development
    orchestration frameworks like kubernetes
    took on the responsibilities of the
    coordination configuration and
    management of containers
    in deployment environments kubernetes
    version 1.0 was released at the same
    time the cncf was announced
    kubernetes was contributed by google and
    was the first project
    that was brought into the cncf right on
    the heels of that first release
    version 1.5 came out which included the
    container runtime
    interface the cri and that there’s that
    word again
    run time so what exactly is the
    container runtime interface
    that cri is a level of
    abstraction that allowed the kubernetes
    um kublets to support alternative
    low-level container runtimes
    um the docker the company also a member
    of the cncf
    and well on their way to breaking up
    that huge tech stack
    we know as docker contributed their cra
    compatible runtime called container d
    container d was developed in order to
    integrate run c
    into docker version 1.11.
    all right congratulations you made it
    through that history lesson i know that
    was a lot of information and you might
    have even more questions now
    but you have some description of a lot
    of those keywords a lot of the main
    projects that you hear about in the
    ecosystem
    um hopefully you won’t be so bogged down
    with all of that
    new project information um when you
    begin on your
    darker journey
    [Music]
    so docker does all of these things in
    this list
    and it does it well well enough that its
    popularity is unmatched here
    note that when you hear of talk of
    container run times or
    image formats what’s being discussed is
    a small piece of that whole package that
    entire
    tech stack which is described here the
    ability to define a container
    building an image of a container
    managing those images
    distributing and sharing those images
    creating a container environment and
    the concern of launching and actually
    running a container on your machine
    and then of course managing the life
    cycle of those container instances
    let’s talk a little bit more about
    container run times
    this can be really confusing for someone
    new to the world of containers
    the docker tech stack obviously contains
    a lot more than just
    the runtime docker did quite a bit of
    reorganizing their code base
    over the last several years developing
    abstractions and pulling out discrete
    functionality
    one of the results of this effort was a
    project called run c
    which i mentioned before which was
    contributed to the oci
    this was the first and for some time the
    only
    implementation of a low-level container
    runtime that implemented the
    oci runtime specification there are
    other runtimes out there
    and as of this writing this is a very
    active space so be sure to reference the
    current list that is maintained by the
    oci
    for the most up-to-date information and
    i can provide you those links i actually
    have some links at the end of this slide
    deck that will help you get there
    other notable low-level runtime projects
    include
    crun an implementation in c
    that was led by red hat and railcar
    an implementation in rust which was led
    by oracle
    that project is now archived but it’s
    interesting
    developing a specif a specification
    is really challenging and collaboration
    on the oci runtime specification
    wasn’t any less challenging figuring out
    where those boundaries are
    what should and what should not be
    included in the spec
    took some time before the release of
    version 1.0
    it is very clear however just
    implementing that
    specification isn’t enough to drive
    adoption of an implementation
    additional features are needed to make a
    low-level runtime usable for developers
    since we’re concerned with much more
    than just the creation and running of a
    container
    this leads us to higher level runtimes
    like container d
    and cryo
    these runtimes include solutions for
    many of the other concerns around
    container orchestration
    including image management and
    distribution
    both of these runtimes implement the cri
    which eases that path to a kubernetes
    deployment
    both of them delegate low-level
    container activities
    to the oci compliant low-level run times
    like run c
    that brings me to a point a question
    that i get a lot
    this here is a link to a really good
    blog
    in short uh kubernetes is deprecating
    the docker runtime
    and that caused a lot of panic really
    because um
    i think most people don’t understand
    what that actually means
    in short that deprecation of docker
    runtime support
    does not in any way shape or form mean
    that docker is going anywhere
    or losing support in other ways you can
    still use docker to develop and produce
    docker images
    and containers as you do now
    basically what happened is
    docker was originally the docker runtime
    was originally
    the original implementation of cri
    compliance but it was through a specific
    uh component called the docker shim
    that uh basically kubernetes wanted to
    get rid of that
    it was it was a customization that
    wasn’t necessary for any of the other
    runtimes
    plus when docker hit version 1.11
    they started using container d which is
    cri compliant so it really doesn’t make
    any sense
    for kubernetes to support the entire
    docker tech stack
    anymore in order to support that docker
    runtime
    all right we’re getting to the end here
    now we get into just some simple
    terminology of containers
    um what is a container exactly it’s a
    it’s a running instance on your machine
    what is a container image that’s an
    immutable executable binary used to
    create a container
    this is usually a made up of
    made by a docker file which is
    a text file that is a set of
    instructions that is used to
    build that image
    an image tag indicates the version of
    the image
    excuse me a container registry
    is a library of container repositories
    and images
    and the most popular example is docker
    hub that is the
    um the default
    um central storage for docker images
    and an image repository that stores all
    of the versions and tags of an image
    so generally it’s that’s the image name
    all right what now you have all of this
    information you’ve got some terminology
    behind you
    now it’s time to just download docker
    desktop
    um back when i first downloaded
    this application excuse me
    i’ve got a frog in my throat i work for
    jfrog and that’s what happens
    anyway um back when i first downloaded
    docker desktop
    it it was simple it was easy to work
    with
    but when i look at it today so many
    improvements have been made around the
    ui
    you don’t even have to use command line
    commands to
    look at your images or look at the info
    behind them
    any of that you can do that all through
    the ui now it’s pretty cool
    the documentation at docker.com is
    abs it’s very very good um
    they have a whole getting started
    section which is definitely worth
    working through
    the um cncf website
    is here um you can find a lot of
    information about how to get
    involved in those organizations it’s
    really important
    that um companies and organizations get
    involved in these
    so that we move in the right direction
    for future components
    on future development around cloud
    native technologies
    and then of course opencontainers.org
    this is where you can find all of the
    links
    to all of the specifications that i
    talked about earlier um
    the runtime specification includes a
    um a reference to like all of the
    current implementations
    that are available right now and if you
    go there
    you can find not only the current
    low-level container runtimes
    but you can also find as work that’s
    being done
    in vms as well
    all right i am ready for some questions
    if you have any i think we have a couple
    minutes before we start with our next
    speaker
    so i don’t know if anything came up i’m
    going to take another drink
    i was just going to single throat
    yeah there’s there’s uh you know we have
    frogs but i mean
    we never have but you know this is uh
    this is taking it to the extreme i love
    it
    let me ask america would you would you
    prefer to um answer some questions to go
    on to the youtube channel and take some
    questions there in the chat
    uh you can drink as much water as you
    want
    and uh i’m putting in a cough drop right
    now
    i would like to answer these this
    question that’s up here for sure
    sure absolutely okay what does it mean
    by being applica
    by an application being container aware
    as is a container is subset os which can
    run application in isolation
    okay so mainly what i mean is um
    for java applications specifically uh
    the way the jvm
    handled resources for example when you
    launch a container
    you can tell that container only use
    this much of memory on the host
    only use this much of processing power
    on the host
    but for a java application for older
    versions
    it ignored that it was it wasn’t using
    it was getting the wrong number
    basically so you could launch a bunch of
    containers on an
    os and then they could all stomp on each
    other because they’re all taking
    resources from each other
    so that’s what i meant by container
    aware
    there wasn’t good enough isolation there
    thank you that’s awesome also there was
    a git repo
    you were talking about somebody who
    actually wanted to know if you could
    share the get repo
    uh information a get repo
    yeah i think it was near the beginning
    of the talk um
    maybe you made a reference to one uh
    made reference to one
    i may have let me go find it um it might
    be the open containers
    [Music]
    you