Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Containerization primatives
Search
Sam Kottler
November 05, 2014
Technology
0
150
Containerization primatives
Sam Kottler
November 05, 2014
Tweet
Share
More Decks by Sam Kottler
See All by Sam Kottler
This is your database on Linux
skottler
0
290
How to Debug Anything - DevOpsDay PGH
skottler
1
1.2k
Icinga at DigitalOcean
skottler
1
1k
PuppetConf '14
skottler
0
230
Configuration Management Anti-Patterns
skottler
2
1.2k
Other Decks in Technology
See All in Technology
衛星画像超解像化によって実現する2D, 3D空間情報の即時生成と“AI as a Service”/ Real-time generation spatial data enabled_by satellite image super-resolution
lehupa
0
190
GoでもGUIアプリを作りたい!
kworkdev
PRO
0
160
やる気のない自分との向き合い方/How to Deal with Your Unmotivated Self
sanogemaru
1
530
Introdução a Service Mesh usando o Istio
aeciopires
1
240
SCONE - 動画配信の帯域を最適化する新プロトコル
kazuho
1
210
事業開発におけるDify活用事例
kentarofujii
3
990
『バイトル』CTOが語る! AIネイティブ世代と切り拓くモノづくり組織
dip_tech
PRO
1
130
Kubernetes self-healing of your workload
hwchiu
0
240
FinOps について (ちょっと) 本気出して考えてみた
skmkzyk
0
180
[VPoE Global Summit] サービスレベル目標による信頼性への投資最適化
satos
0
150
AI時代におけるデータの重要性 ~データマネジメントの第一歩~
ryoichi_ota
0
700
Biz職でもDifyでできる! 「触らないAIワークフロー」を実現する方法
igarashikana
3
1k
Featured
See All Featured
How to Create Impact in a Changing Tech Landscape [PerfNow 2023]
tammyeverts
55
3k
GitHub's CSS Performance
jonrohan
1032
470k
Leading Effective Engineering Teams in the AI Era
addyosmani
7
510
The Illustrated Children's Guide to Kubernetes
chrisshort
49
51k
Designing Experiences People Love
moore
142
24k
The Success of Rails: Ensuring Growth for the Next 100 Years
eileencodes
46
7.7k
Understanding Cognitive Biases in Performance Measurement
bluesmoon
31
2.7k
GraphQLの誤解/rethinking-graphql
sonatard
73
11k
Design and Strategy: How to Deal with People Who Don’t "Get" Design
morganepeng
132
19k
Responsive Adventures: Dirty Tricks From The Dark Corners of Front-End
smashingmag
253
22k
Building Applications with DynamoDB
mza
96
6.7k
Principles of Awesome APIs and How to Build Them.
keavy
127
17k
Transcript
CONTAINERIZATION PRIMITIVES Sam Kottler @samkottler
ABOUT ME • Work at DigitalOcean as a systems engineer
• Formerly of Red Hat, Venmo, Acquia • Committer/core for Puppet, Ansible, Fedora, CentOS, RubyGems, Bundler
WE’RE GONNA BE TALKING ABOUT LINUX
GOOD TO KNOW’S • What is a syscall • Basic
understanding of linux networking • Containers vs. virtualization
WHY DO WE CARE ABOUT ANY OF THIS?
CONTAINERS ARE THE PAST *, PRESENT, AND FUTURE * Most
of the linux ideas are poached from other OS’s
VIRTUALIZATION HAS BECOME MASSIVELY POPULAR BECAUSE OF ITS ECONOMICS
CONTAINERS ARE BECOMING MASSIVELY POPULAR BECAUSE THEY ALLOW LOGICAL SEPARATION
APPLICATION VS. FULL CONTAINERS
NETWORKS, USERS, AND PROCESSES
NAMESPACES • mnt: filesystem • pid: process • net: network
• ipc: SysV IPC • uts: hostname • user: UID
THE BASICS • Namespaces do not have names • Six
inodes exist under /proc/<pid>/ns • Each namespace has a unique inode
USERSPACE TOOLING • iproute2 • util-linux • systemd
NAMESPACE SYSCALLS • unshare() • moves existing process into a
new namespace • clone() • creates new process and namespace • setns() • joins an existing namespace
NETWORK ISOLATION • One namespace per networking device • Single
default namespace, init_net(*nets) • A lo device is included in every ns_net.
NETWORK NAMESPACES IN PRACTICE • ip netns add testns1 •
creates /var/run/netns/testns1 • route management per-NS • prevents cross-NS bonds • setns(int fd, int nstype) • validates namespace type vs. FD
SOCKET ISOLATION • Sockets are mapped into network namespaces •
Also part of a single network namespace • sk_net is part of the sock struct • sock_net()/sock_net_set() getter/setter
SOCKET ACTIVATION • Listen on a socket, but have no
services behind it • Request arrives, service is spun up, responds • Enabling 10k+ low-usage services on a VM
USER ISOLATION • Allows non-privileged usage • Often used as
the start of a namespace chain • UID’s come from the overflow rules
CGROUPS • Resource management • Around since 2006/2007 • Widely
used by userspace management tools
CGROUPS + NAMESPACES • “This PID can only see part
of the filesystem” • “This PID can only see part of the filesystem, use 384mb of memory, and utilize a single CPU.”
CGROUP IMPLEMENTATION • Hooks into fork() and exit() • VFS
of a new type called “cgroup” • More complex descriptors for task_struct • Procfs entry in /proc/<pid>/cgroup • All actions take place on the FS
CGROUP MANAGEMENT • 4 files per-cgroup • tasks • cgroup.procs
• cgroup.event_control • notify_on_release
CPU • Split into “shares” • Default is 2048 shares
• Linear CPU time use
MEMORY • Exposes most of the memory subsystem • NUMA
management • Most complex type of cgroup
LETS TALK ABOUT SECURITY…
SHARING A KERNEL IS INHERENTLY LESS SECURE
KERNEL VULNERABILITIES AROUND BREAKOUT ARE USUALLY MITIGATED BY RUNNING SERVICES
NON- PRIVILEGED
THANKS! • @samkottler • https://github.com/skottler •
[email protected]