This document discusses choosing the right storage option for Kubernetes workloads. It begins by distinguishing between stateful and stateless applications, and describes Kubernetes storage concepts like volumes, persistent volumes, persistent volume claims and storage classes. It then reviews various cloud native storage options and traditional solutions that integrate with Kubernetes via the container storage interface (CSI). Key factors for choosing storage are listed like support for VMs and containers, replication features, performance, encryption and portability. Common challenges with storage options are also outlined. The document emphasizes testing multiple solutions, considering licensing, and aligning with enterprise strategies when selecting storage for Kubernetes.

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Choosing Right Storage
for Kubernetes
Abhinivesh Jain
Distinguished Member of Technical Staff
12-Aug-2021

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About Me
@AbhiniveshJain
/abhiniveshjain
Author,
Speaker and
Blogger
Open Source
“Contributor”
Working as
Distinguished
Member of
Technical Staff
(DMTS)-
Senior
Member in
CTO-5G Team
in Wipro

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Agenda
01
Stateful and
Stateless Workloads
02
Kubernetes
storage concepts
03
Storage fabric
options
04
Choosing the right
storage
05
Lesson learnt
06
Key Takeaways

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01
Stateful and Stateless
applications
04
Choosing the right
storage
02
Kubernetes
storage concepts
03
Storage fabric
options
05
Lesson learnt
06
Key Takeaways
Agenda

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Stateful Vs Stateless workloads
01 02 03
04 05 06
Kubernetes
was originally
built for
stateless
workloads
Stateless
workloads
are not
affected by
POD restarts
Stateful
workload
needs to
preserve the
state after
POD restart
Stateful
workloads
examples-
Databases
Stateful
workloads
requires use
of permanent
storage
Stateful
workloads is
not same as
Statefulsets

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Agenda
01
Stateful and
Stateless Workloads
04
Choosing the right
storage
02
Kubernetes
storage concepts
03
Storage fabric
options
05
Lesson learnt
06
Key Takeaways

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Kubernetes storage concepts
1
2
3
4
5
Volumes
Persistent Volume (PV)
Persistent Volume Claim (PVC)
Storage Class
hostPath

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K8s Storage concepts- Volume
awsElasticBlockStore
azureDisk
azureFile
cephfs
cinder
configMap
downwardAPI
emptyDir
fc (fibre channel)
gcePersistentDisk
glusterfs
hostPath
iscsi
local
nfs
persistentVolumeClaim
portworxVolume
projected
quobyte
rbd
secret
storageOS
vsphereVolume
Volume is a
Directory
2 Types
Ephemeral Volume
Persistent Volume (PV)
Ephemeral Volume-
Lifetime of a POD
Kubernetes
supports several
volume types

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Persistent Volume(PV)
apiVersion: v1
kind: PersistentVolume
metadata:
name: cncf-demo-pv
labels:
type: local
spec:
storageClassName: manual
capacity:
storage: 1Gi
accessModes:
- ReadWriteOnce
hostPath:
path: "/mnt/data"
Piece of storage Static or Dynamic
Can use several different
types of PV in same POD

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Persistent Volume Claim(PVC)
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: cncf-pv-claim
spec:
storageClassName: manual
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
POD uses PVC to get
storage
PVC consumes PV
resources
PVC to PV binding is one to
one mapping

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Storage Class
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: cncf-ebs-sc
provisioner: kubernetes.io/aws-
ebs
parameters:
type: io1
iopsPerGB: "10"
fsType: ext4
Useful for Dynamic PV
provisioning
Known as profiles in
various storage systems
Use regional-pd for
replication of data between
two zones
Different options/features
supported by different
vendors

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HostPath
apiVersion: v1
kind: PersistentVolume
metadata:
name: cncf-demo-pv
labels:
type: local
spec:
storageClassName: manual
capacity:
storage: 1Gi
accessModes:
- ReadWriteOnce
hostPath:
path: "/mnt/data"
Type of Persistent volume
Useful for non-prod
environment
Has several security risks
Not recommended for
Production
Uses a file or directory
on node

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Agenda
01
Stateful and
Stateless Workloads
04
Choosing the right
storage
02
Kubernetes
storage concepts
03
Kubernetes
Storage Options
05
Lesson learnt
06
Key Takeaways

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Cloud Native Storage Options
56 options as of 25th July 2021
Source: https://landscape.cncf.io/?category=cloud-native-storage&grouping=category

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Cloud Native Storage Options- CNCF Projects
Trivia: OpenEBS is used in production in CNCF.
Source: https://landscape.cncf.io/?category=cloud-native-storage&grouping=category

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Cloud Native Storage Options- Graduated Project
Only Graduated Project in Cloud Native Storage landscape
Source: https://landscape.cncf.io/?category=cloud-native-storage&grouping=category

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Types of Kubernetes Storage
1
2
3
Traditional Solution with CSI plug-in
Software Defined Storage (SDS) with
container optimization
Cloud native solutions

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Agenda
01
Stateful and
Stateless Workloads
04
Choosing the Right
Storage Option
02
Kubernetes
storage concepts
03
Storage fabric
options
05
Lesson learnt
06
Key Takeaways

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Decision Criteria
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Supports both VM and Containers
Supports Block, Object and Filesystems
Enterprise support available
Supports major cloud providers
Provides replication feature
Provides Async replication
Provides Sync replication
Provides deduplication and compression
Ease of deployment
Provides workload migration feature
High performance at scale
Point in time snapshot feature
QoS guarantee
Encryption at rest
Encryption in motion
Checksum error detection
Scales with Nodes
No Infra lock-in
Backup and recovery feature
Thin provisioning

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Agenda
01
Stateful and
Stateless Workloads
04
Choosing the right
storage
02
Kubernetes
storage concepts
03
Storage fabric
options
05
Lesson learnt
06
Key Takeaways

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Lesson Learnt
01
02
03
04
Shortlist max 5
solutions in the
beginning
Some limitations will
be known only during
the POC.
Subscription/licensing
of add-ons should be
considered in the
beginning itself.
Join Slack channel
to get faster support

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Common
Challenges

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Common Challenges
1
2
3
4
5
Fast changing area
Lack of support for VMs and Containers both
Error prone- command-line based steps
Lack of application awareness
Missing features around Replication and
Disaster recovery

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Agenda
01
Stateful and
Stateless Workloads
04
Choosing the right
storage
02
Kubernetes
storage concepts
03
Storage fabric
options
05
Lesson learnt
06
Key Takeaways

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Key Takeaways
03
Few vendors give their as-is commercial version
with several restrictions. This is usually a good
option for non-prod environments.
05
End to end Automation and GUI driven
configuration is not available in most of the
products
02
Most vendor supported products do not give
exact same commercial version features in
Open-source version
04
Give special consideration for performance
requirements
06
No “one size fits all” solution
Alignment with enterprise strategy, Enterprise
support and features are usually three main
decision criteria
01

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Wipro today
IT Services Revenue
in FY 2020-21*
Active
global clients*
Employee
Count*
Countries with
Employee presence*
$8.13 Bn 1120 66
197,712
*Figures based on FY 2020-21 for Global IT Services business.

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