Kubernetes is a production grade container orchestration system and one of the most popular open source projects released by Google. {code} by Dell EMC is focused on bringing a common storage interface. Kubernetes boasts a unique architecture and fresh perspective on running containerized applications used by companies like SoundCloud and The New York Times. Learn all about Kubernetes and see how {code} by Dell EMC is integrating REX-Ray to provide stateful application support to pods of containers.

1. Google does containers:
Hello Kubernetes
Steve Wong
Open Source Engineer
@cantbewong
{code} by Dell EMC

2. presenter
Steve Wong
Open Source Engineer
{code} by Dell EMC
@cantbewong
Vladimir Vivien
Open Source Engineer
{code} by Dell EMC
@VladimirVivien

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Open source at Dell EMC
– Contribute to meaningful OSS projects
– Create new thought leading OSS applications
– Drive awareness of OSS opportunities with Dell EMC
product teams
– Participate in relevant community engagement projects
– Act in the interest of building a community
{code} by Dell EMC is a group of passionate open
source engineers and advocates working to build a
community around software-based infrastructure.
Platinum SponsorPlatinum Sponsor

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In the beginning: The monolith
Linux
Apache
PHP, Perl,Python
libs

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Lift and shift VM to container: Does it work?
Linux
Apache
PHP, Perl,Python
libs
Linux
Apache
PHP, Perl,Python
libs

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Containers
Linux
Apache
PHP, Perl,Python
libs libs libs
Linux
Apache
PHP, Perl,Python
libs

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Container vs VM
• Faster deploy time
• Simplified dependencies
• Less Work for you:
• Common open
source components
are being published
as containers
• Container images more
compact than OVA’s
• More compact
catalog storage
• Faster network copy
+ deploy

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Let’s look at N-tier

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Other Containers Advantages
They make managing applications easier
• Speed up software innovation
• Deployments are simple
• Creates portable, shareable
and reusable units of code
and requirements
Code Code and requirements Container

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Container workload portability
• Creates portable, shareable
and reusable units of code and
requirements
• Runs in any cloud, including
“bare metal on prem” and “your
laptop”
Code Code and requirements Container
Goal: Write once, run anywhere

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But packaging and distributing images is
a small part of deploying micro-services
Discovery
Scaling Security
Monitoring Configuration
SchedulingHealth
Network

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• Open source, open API container
orchestrator
• Manage applications, not
machines
• Supports multiple cloud and
bare-metal environments
• Inspired and informed by Google’s
experiences and internal systems
– Over 12 years
– 2B deployed each week
Kubernetes

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History
• Kubernetes (Greek for "helmsman" or "pilot")
• Its development and design are heavily influenced by Google’s internal
Borg system and many of the top contributors to the project previously
worked on Borg.
• The original name for Kubernetes within Google was project Seven of
Nine, a reference to a Star Trek character that is a 'friendlier' Borg
– Google's lawyers rejected taking the internal codename public, thus the
Kubernetes name. The seven spokes on the wheel of the Kubernetes logo is
an acknowledgment of the bannished name.
• Kubernetes v1.0 was released on July 21, 2015.

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What is Kubernetes?
From a resource perspective:
•It’s a cluster manager
– Pools Computers into a centrally managed resource pool managed
as a unit
From an application perspective
•It’s a scheduler (= dispatcher)
– Dispatches workloads which consume the pooled resources

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Kubernetes is based on controller loops
• Drive current state -> desired state
• Act independently
• APIs - no shortcuts or back doors
• Observed state is truth
• Recurring pattern in the system

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Child
• Go upstairs
• Get undressed
• Put on pajamas
• Brush your teeth
• Pick out 2 stories
Employee
• Go get some sleep
Desired State: like managing children vs employees

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There should be:
3 Frontends
2 Services
1 Backend
Example:
desired state
automation of scale-out

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Cattle
• Has a number
• One is much like any other
• Run as a group
• If it gets ill, you make hamburgers
Pet
• Has a name
• Is unique or rare
• Personal Attention
• If it gets ill, you make it better
Cattle vs Pets = Kubernetes can do both

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Architecture /Components

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Kubernetes Aerial view
users master nodes

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• The atom of scheduling for containers
• One or more containers and volumes
• Each has its own routable (no NAT) IP
address
• IP and storage shared across pod
• Emphemeral – gets new ID if killed and
reborn

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Deployment/ReplicaSet
• Specify desired number of instances
• Kubernetes monitors health
• Automates driving actual toward desired

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The journey to the cloud..
sounds all white and fluffy,
After all, what could possibly
go wrong?

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What could possibly go wrong?
– Hardware failure
– Software failure
– File system corruption
– Accidental deletion

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Kubernetes controller model
1. Observe 2 instances
2. Declared desired instances is 3
3. Initiate automated deployment of a replacement

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Services
• Provide
• Discovery
• Load balancing
• A stable address
(internal or external)

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External Persistent Storage
• Pods are ephemeral and stateless
• Volumes bring persistence to Pods
• Kubernetes volumes are similar to
Docker volumes, but managed
differently
• All containers within a pod can
access the volume

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External Volume Mount Addresses
• Availability Risk
– Migrate container to another host – your
storage is gone
– Host goes down – your service goes
down
• Scale Limitation
– Need more storage than the host has?
Sorry…

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Storage Classes and dynamic provisioning

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StatefulSets
• Goal: enable clustered multinode software
on Kubernetes
• MySQL
• PostgreSQL
• Zookeeper
• These need “identity” and sequencing
guarantees
• Stable hostname available in DNS
• Ordinal index for instances
• Stable storage linked to ordinal + hostname
• Discovery of peers
• Startup/Tear down ordering

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Storage for Kubernetes Persistent Volumes
• Kubernetes offers two approaches for storage
integration.
– An “in-tree” volume plugin for a platform. The
storage interface code is directly embedded into
Kubernetes. The downside is that plugin velocity
(the speed at which a plugin can be added,
enhanced, or patched) is gated by the Kubernetes
release cycle.
– The second approach is to leverage the
FlexVolume volume plugin. This plugin uses
externally installed and managed software to
handle basic Attach/Detach/Mount/Unmount
storage operations.

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Kubernetes Integration
• ScaleIO is part of the core Kubernetes code and a first
class native storage provider
– ScaleIO can take full advantage of the Kubernetes volume
lifecycle features including dynamic provisioning and
storage classes
– ScaleIO driver is embedded in the standard distribution of
Kubernetes
– Contributed code from the {code} by Dell EMC team
passes “Google” standard of quality
– Opens a new opportunity for those running Kubernetes in
on-premise data centers. It allows utilization of your
commodity x86 server hardware for very high performance
and highly available storage for running stateful apps in
containers.

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Kubernetes Integration
• REX-Ray provides an adapter script called FlexRex
which integrates with the FlexVolume plug-in to interact
with the backing storage system
– Allows pods to consume data stored on volumes that are
orchestrated by REX-Ray. Using Kubernetes' FlexVolume
plug-in, REX-Ray can provide uniform access to storage
operations such as attach, mount, detach, and unmount for
any configured storage provider.
– Run stateful applications in pods and stateful sets through
FlexREX, and benefit from CLI management capabilities.
– Use any REX-Ray supported storage platform
– Dynamic Provisioning and storage classes are not available
as a limitation of FlexVolume and requires volume
create/delete to be managed outside of Kubernetes
$ rexray flexrex install

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Demo!

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{code} by Dell EMC is a group of
passionate open source engineers and
advocates working to build a community
around software-based infrastructure.
rexray.codedellemc.com
github.com/codedellemc/labs
Steve Wong
@cantbewong
github.com/cantbewong
#codeopen
HOL01 Use REX-Ray & ScaleIO w/ Docker, Mesos and Kubernetes