THE AGENDA • Brief History • The Container Market • What is Docker? • What is a Container? • Container Gotchas
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HOW ARE YOU USING CONTAINERS TODAY??? • LOCALLY • TEST/QA ENVIRONMENTS • PRODUCTION • WE DON’T USE THEM TODAY • WE ARE CONSIDERING USING THEM
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ALL ABOUT … CONTAINERS
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SHARING LIMITED RESOURCES
1979 / 1982- chroot
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PROGRESS TOWARD VIRTUALIZATION ▪ 2000 - FreeBSD jail ▪ 2004 - Solaris Zones / snapshots ▪ 2006 - Google Process Containers / cgroups ▪ 2008 - IBM LinuX Containers (LXC) ▪ 2013 - Docker (open source!) - Google LMCTFY (open source!) ▪ 2014 - Docker trades LXC for libcontainer ▪ … more stuff happened
1 201 7 a v a J
2014 Java 8
▪ June 2015 - Open Container Project/Initiative (OCI) ○ Runtime Specification (runtime-spec) ○ Image Specification (image-spec) ▪ … even more stuff happened and is still happening!
THE CONTAINER MARKET (according to Sysdig)
2019 - 2 million Containers (includes both SaaS & on prem users)
Fig. 2. 2019 Container Runtimes from: “Sysdig 2019 Container Usage Report: New Kubernetes and security insights,” 29 Oct. 2019, sysdig.com/blog/sysdig-2019-container-usage-report/. Accessed 10 Jun. 2020.
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THE CONTAINER MARKET (according to Sysdig)
2020/21 - 2 million Containers (a subset of customer containers)
Fig. 3. Container runtimes from: “REPORT.2021 Container Security And Usage Report,” Jan 2021, https://dig.sysdig.com/c/pf-2021-container-security-and-usage-report?x=u_WFRi. Accessed 21 Jan. 2021.
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WHAT EXACTLY IS DOCKER? 17
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WHAT DO WE ACTUALLY NEED/WANT? • An isolated environment where a user/application can operate, sharing the host system’s OS/kernel without interfering with the operation of another isolated environment on the same system (a container) • A way to define a container (an image format) • A way to build an image of a container • A way to manage container images • A way to distribute/share container images • A way to create a container environment • A way to launch/run a container (a container runtime) • A way to manage the lifecycle of container instances 18
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DOCKER, THE WHOLE PACKAGE docker images
DOCKER ENGINE DOCKER IMAGE FORMAT Dockerfile docker build
docker rm docker push docker pull DOCKER HUB docker run docker stop docker ps 19
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BREAKING UP THE MONOLITH OCI IMAGE FORMAT • Docker V2 Image Spec
OCI CONTAINER RUNTIME • runC (which used to be libcontainer… which was written by Docker)
OTHERS - containerd, rkt, cri-o, Kata, etc… https://lwn.net/Articles/741897/ https://www.ianlewis.org/en/container-runtimes-part-1-introduction-container-r 20
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WHAT EXACTLY IS A CONTAINER? 22
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CONTAINER COMPONENTS TARBALL OF A FILESYSTEM LINUX FEATURES • namespaces • cgroups • Union File systems
Mix these together to create and run a container! Voila! https://docs.docker.com/get-started/overview/ 23
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FILESYSTEM DETAILS …
… NOTE: On OSX, containers will actually be running in a tiny Linux VM (use screen) screen ~/Library/Containers/com.docker.docker/Data/vms/0/tty
screen ~/Library/Containers/com.docker.docker/Data/vms/0/tty
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FILESYSTEM DETAILS
…
…
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FILESYSTEM DETAILS
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CONTAINER GOTCHAS
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CONTAINER GOTCHAS - RUNNING AS ROOT
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CONTAINER GOTCHAS - NO CONSTRAINTS
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CONTAINER GOTCHAS - NEVER UPDATING
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CONTAINER GOTCHAS - JAVA/JVM GOTCHAS
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CONTAINER GOTCHAS - IMAGE BLOAT
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MANAGING YOUR IMAGES - REMOTE BY DEFAULT START FREE: http://bit.ly/JFokus_Free_DevOps_Tools
https://dzone.com/refcardz/getting-started-with-container-registries 33
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THE SWAG - DON’T FORGET!
http://bit.ly/JFokusJFrog2021