CONTAINer Runtimes

Draw Some Lines

 

Devconf.IN 2019 Bangalore, IN

Vincent Batts @vbatts

$> finger $(whoami)
Login: vbatts                           Name: Vincent Batts
Directory: /home/vbatts                 Shell: /bin/bash
Such mail.
Plan:
OHMAN
$> id -Gn
devel opencontainers docker appc redhat golang slackware

Containers

(Cite: the internet)

Containers

(Cite: The Internet)

Container Runtimes

chroot + unshare (mnt ns) + cgroups

a history

LXC

systemd-nspawn

Container Runtimes

a history

Docker

  • all the things
  • 2013 python script became golang
  • (not a single good link to the source)

lmctfy

  • 2013
  • academic offering
  • dead, but still a good example of form over function

rkt

  • Dec 2014
  • spec-first design (appC spec)

Container Runtimes

a history

libcontainer (now runc)

  • 2014
  • to have something golang native, rather than shell-out to lxc
  • (eventually meant more shelling-out)
  • the original OCI runtime

  lxd

  • 2014
  • container manager built on lxc
  • (came after Docker made asks of lxc, then abandoned it for libcontainer)

libct

  • from odis/openVZ folks
  • C library of container helpers (not docker or lxc related)

Container Runtimes

a history

OCI Specification

Container Runtime Interface

Kubernetes

  • 2014
  • was (is?) entirely too docker-centric
  • with rkt it was clear there were big changes needed
  • Enter CRI (2016)
    • gRPC interface for ImageService and RuntimeService

migration via dockershim

  • completely switched to docker via CRI in v1.8

(source)

Container Runtime Interface

cri-o (originally oci-d)

  • kubernetes only use-case
  • OCI images and runtime
  • primarily called runc, but is flexible to call other runtimes

containerd

  • primarily docker use-case, but includes a CRI shim
  • OCI and Docker images

alibaba/pouch

  • swiss arm knife of sorts
  • uses kvm pieces
  • supports 2.6.32+ kernel
  • imports from runc, docker, p2p backend, and expose a CRI socket

Container Runtime Interface

cri-tools

  • `crictl`
  • the cli for working or debugging directly with CRI layer

OCI RUNTIMES

oracle/railcar

  • 2017
  • an OCI runtime
  • written in rust

kata-containers (formerly clear containers and hyperV)

  • mixed years
  • an OCI runtime
  • thinVM (qemu with custom machine type)

openconatainers/runc

  • 2014
  • to have something golang native, rather than shell-out to lxc
  • (eventually meant more shelling-out)
  • the original OCI runtime

OCI RUNTIMES

nvidia fork of runc

  • inherently an OCI runtime
  • exposes GPU specific configuration

google/gvisor (`runsc`)

  • has an OCI runtime
  • syscall emulation layer
  • uses a bit of kvm
  • feels a bit like thrown over the wall

windows/hcsshim (`runhcs`)

  • has an OCI runtime
  • windows native container API

nabla-containers (IBM research)

  • has an OCI runtime
  • unikernel approach
  • requires tailored container images with their executor

OCI RUNTIMES

systemd-nspawn native support (pr9762)

  • preferable than wrapper
  • still has a couple of pieces missing like hooks and compatible cli

non-docker options

podman

  • easy alias for `docker`
  • direct invocation
  • now supports non-root

buildah

  • drop-in for `docker build`, as well as shell subcommands
  • direct invocation
  • now supports non-root builds

umoci

  • utility for working with OCI container images
  • unpack, modify, repack

skopeo

  • initially just remote inspect images
  • now copies (local <=> remote) and translates formats

github.com/vbatts/talks

Thanks!

Vincent Batts

@vbatts| vbatts@redhat.com