Zero-to-Hero: Running Postgres in Kubernetes

CONFIDENTIAL © Copyright EnterpriseDB Corporation, 2019. All rights reserved.
Zero to Hero
Running Postgres in Kubernetes
Taylor Graham : Field CTO
Twitter: @thecloudslayer
1

CONFIDENTIAL © Copyright EnterpriseDB Corporation, 2019. All rights reserved.2
WHO IS RUNNING K8S ON LAPTOP?

WHO
2019 Container Adoption Survey - Diamanti

WHAT

WHERE

WHY
• Business: Kubernetes is a system for deploying applications that
can save money because it takes less IT manpower to manage
and helps more efficiently utilize the infrastructure. It helps
make your apps a more portable, so you can move them more
easily between different clouds and internal environments or
laptop to laptop.
• Tech: Agility in development, deployment, and operations

BASIC CONCEPTS

CLUSTER
• Doc: I could not find a
definition.
• Taylor: A Kubernetes
cluster is everything.

MASTER
• DOC: The Kubernetes Master is a collection of three processes
that run on a single node in your cluster, which is designated as
the master node. Those processes are: kube-apiserver, kube-
controller-manager and kube-scheduler.The Kubernetes master
is responsible for maintaining the desired state for your cluster.
• Taylor: I would call it the
brains / command and control.
I would think of it like vCenter
coming from that world.

CLUSTER COMMANDS
Kubectl cluster-info
Kubectl version

NAMESPACE
• Doc: Namespaces are a way to divide
cluster resources between multiple users.
Namespace provide a scope for names.
Names of resources need to be unique
within a namespace, but not across
namespaces. Namespaces can not be
nested inside one another and each
Kubernetes resource can only be in one
namespace.
• Taylor: It’s a good way not to blow
everything up ASAP.

NAMESPACE COMMANDS
helm install edb-2.4.2.tgz -f myvalues.yaml –namespace anotherfailwhale
Kubectl create namespace anotherfailwhale

NODES
• Doc: A node is a worker machine in Kubernetes, previously known
as a minion. A node may be a VM or physical machine, depending
on the cluster. Each node contains the services necessary to
run pods and is managed by the master components. The services
on a node include the container runtime, kubelet and kube-proxy
• Taylor: The physical server
or virtual machine running
all the magic.

NODE COMMANDS
NODE COMMANDS
Kubectl get nodes

POD
• Doc: A Pod is the basic execution unit of a Kubernetes
application–the smallest and simplest unit in the
Kubernetes object model that you create or deploy. A Pod
represents processes running on your Cluster.
• Taylor: Because they
share a local host with
all containers in pod I
think of it like docker-
compose on your
laptop.

POD COMMANDS

AND MORE POD COMMANDS
kubectl describe pod

SERVICE
• Doc: a Service is an abstraction which defines a
logical set of Pods and a policy by which to
access them. The set of Pods targeted by a
Service is usually determined by a selector.
• Taylor: what the doc said….

PV/PVC
• Doc: A PersistentVolume (PV) is a piece of storage in the cluster that
has been provisioned by an administrator or dynamically provisioned
using Storage Classes. A PersistentVolumeClaim (PVC) is a request
for storage by a user. It is similar to a pod. Pods consume node
resources and PVCs consume PV resources.
• Taylor: LUN and VMDK

PV

DEPLOYMENT / REPLICASET
• A Deployment controller provides declarative updates
for Pods and ReplicaSets.
• A ReplicaSet’s purpose is to maintain a stable set of replica Pods
running at any given time. As such, it is often used to guarantee the
availability of a specified number of identical Pods.
• Taylor:

STATEFULSET
• Doc: StatefulSet is the workload API object used to manage
stateful applications. Manages the deployment and scaling
of a set of Pods , and provides guarantees about the
ordering and uniqueness of these Pods.
• Taylor: Where you run a
database.
Stable, unique network identifiers. $(statefulset name)-$(ordinal)
Stable, persistent storage.
Ordered, graceful deployment and scaling.
Ordered, automated rolling updates.

DESIGN PATTERNS

© Copyright EnterpriseDB Corporation, 2019. All rights reserved.24
SINGLE NODE
Postgres
Data
Application Database
Stand alone Postgres server
basic configuration
Containers
Pods

© Copyright EnterpriseDB Corporation, 2019. All rights reserved.
metrics
25
HA REFERENCE ARCHITECTURE
Postgres
HA
Agent
Proxy
Mon
Agent
Data
Application
EDB-Service
Postgres
HA
Agent
Mon
Agent
Data
Postgres
HA
Agent
DR
Tool
Proxy
Mon
Agent
Data
Admin
Tool
read/write
readread
redundant
streaming
replication
streaming
replication
Shared or Local Storage
Database, Tools, Agents
Containers
Pods
Application Application
Master Standby 2Standby 1
Proxy
Postgres cluster
with application scale-out
Backup

© Copyright EnterpriseDB Corporation, 2019. All rights reserved.
metrics
26
On-Prem In-Memory Compute Nodes
Postgres
HA
Agent
Proxy
Mon
Agent
EDB-Service
Postgres
HA
Agent
Mon
AgentPostgres
HA
Agent
DR
Tool
Proxy
Mon
Agent
Admin
Tool
read/write
readread
redundant
streaming
replication
Database, Tools, Agents
Containers
Pods
Master Standby 2Standby 1
Proxy
NODE POOL DB PREFORMANCE NODE 2 NODE 3
Volume Claim Volume Claim Volume Claim
Data Data DataBackup
Nodes
ApplicationApplication Application
streaming
replication
17k TPS
PgBench

OK LETS DEPLOY

KUBECTL

HELM
• helm install edb-2.4.2.tgz -f myvalues.yaml

OPENSHIFT

RANDOM THOUGHTS

MONITORING THOUGHTS
Old way
Utilization (U): The percentage of time a resource is in use.
Saturation (S): The amount of work the resource must (the “queue” of work).
Errors (E): A count of errors.
RED methodology
Rate (R): The number of requests per second.
Errors (E): The number of failed requests.
Duration (D): The amount of time to process a request.
RED is actually derived from The Four Golden Signals
Latency: The time it takes to service a request.
Traffic: A measure of how much demand on the system.
Errors: The rate of failed requests.
Saturation: A measure of how “full” a service is, often measured by latency.
OOM KILLER

EVERYTHING ELSE

QUESTIONS & DISCUSSION
34

THANK YOU
info@enterprisedb.com
www.enterprisedb.com
35

Zero-to-Hero: Running Postgres in Kubernetes

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