microcontainers and tools for hardcore container debugging

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. |

Microcontainers and Tools for Hardcore Container Debugging

Vish Ishaya Abrams, TJ Fontaine

September 7th, 2017Container Native Meetup


Who Are We?

• Former Maintainer of Node.js

• Authors of Oracle Open Source Container Utilities

• Founder of OpenStack at NASA


Agenda

What is a Container?

Intro to Microcontainers

Building Microcontainers

Container Debugging

Questions and Answers


WHAT IS A CONTAINER?


A container is:

1. An application bundled with its dependencies (also called a container image).

2. A running copy of that application that has been isolated from other system resources via a container runtime.


Container Workflow

Container Image Repository

Application ContainerImage

Build

Upload Download

ContainerImage

Container

Run

ContainerHost

BuildHost

Container OrchestratorContinuous Delivery System


Container Images

• Like a VM image

• Immutable Bundle

• Application code plus dependencies

• Portable across different hosts


Running Container

• Like a virtual machine

• Protected from host and other applications via:

– Isolation of Owned Resources – Namespaces

– Restriction of Actions – Capabilities

– Limits on Shared Resources – Cgroups


Isolation – Namespaces + Access Control

• Linux Namespaces

– User

– Ipc

– Uts

–Network

–Mount

– Process

• Access Control: SELinux/AppArmor

– Prevents access to other resources in the event of a namespace escape


Restriction – Capabilities + Setuid + Seccomp

• Drop linux capabilities

• Setuid Setgid to limited user and group

• Restrict access to syscalls via seccomp


Limits – Cgroups + Resource Limits

• Cgroups are primarily used to control

–Memory

– CPU

– Block IO

• Other Resource Limits

– Prevent filling up disk (quotas)

– Prevent overloading host daemons (rate limiting)

– Prevent network saturation (qos)


Container Orchestrator

• Primarily designed for stateless microservices

• Schedules work across a fleet of machines

• Keeps multiple copies of an application running

• Allows for dynamic scaling of application

• Defines how applications can communicate


Containerization Operational Changes

• Rebuild instead of security patch

• Different monitoring tools

• Deployment as immutable artifacts

• Build tooling vs configuration management


Worst Practices

• Developers without an operations mentality

• Multiple applications per container

• Lack of CI/CD automation

• Container Bloat

• Handling of security vulnerabilities

Confidential – Oracle Internal/Restricted/Highly Restricted 14


Oracle – Open Source Contributions

railcar

Alternative Docker runtime implemented in Rust following

the Open Container Initiative OCI-Runtime Spec

smith

A simple command line utility for building microcontainers from rpm

packages or Open Container Initiative images.

crashcart

A simple command line utility that lets you side load an image

with linux binaries into an existing container. Facilitates easier

debugging

https://blogs.oracle.com/developers/the-microcontainer-manifesto


INTRO TO MICROCONTAINERS

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 17

Microcontainers


What’s wrong with big containers?

• Large images

–Often > 1GB in size

• Bloat

– I wanted a banana. I got the banana and a jungle and an 800lb Gorilla

• Privilege escalation

–whole Linux user space bigger attack surface

• Vulnerability management

–What files do I really need to patch?


A Microcontainer

• Contains only

– Single executable

– Dependencies (of the executable)

• Runs with a read only root filesystem

• Files are all owned and read by a single user


Result

• Small image

– Eliminate layers reduce complexity

• Fast, easy distribution

• Smaller attack surface

• Certainty over vulnerabilities


BUILDING MICROCONTAINERSDemo


Links

• https://blogs.oracle.com/developers/the-microcontainer-manifesto

• https://github.com/oracle/smith

• https://hackernoon.com/how-to-build-a-tiny-httpd-container-ae622c37db39

https://hackernoon.com/how-to-build-a-tiny-httpd-container-ae622c37db39




CONTAINER DEBUGGINGDemo


Links

• https://blogs.oracle.com/developers/hardcore-container-debugging

• https://github.com/oracle/crashcart

• http://man7.org/linux/man-pages/man1/nsenter.1.html



http://man7.org/linux/man-pages/man1/nsenter.1.html


Safe Harbor Statement

The preceding is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle.


QUESTIONS & ANSWERS


More Information

• Contact Us:[email protected]@oracle.com

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