Manage Pulsar Cluster Lifecycles with Kubernetes Operators - Pulsar Summit NA 2021

Pulsar Virtual Summit North America 2021
Manage Pulsar Cluster
Lifecycles with
Kubernetes Operators
Yang Yang @ StreamNative

About Me
● Software Engineer in StreamNative Cloud
● Open Source Contributor
○ Apache Pulsar
○ Apache BookKeeper
● Alibaba -> Elastic -> StreamNative

StreamNative
Founded by the creators of Apache Pulsar, StreamNative provides a
cloud-native, uniﬁed messaging and streaming platform powered by
Apache Pulsar to support multi-cloud and hybrid-cloud strategies

Apache Pulsar
● Apache Pulsar is a cloud-native, distributed messaging and streaming
platform
○ Fast
○ Highly scalable
○ Lots of powerful features
● Deployment
○ Kubernetes

Deploy Pulsar Clusters on K8s
● Kubernetes is an open-source system for
automating deployment, scaling, and
management of containerized
applications.
○ Consistent, repeatable, reliable
deployments on a wide variety of
systems
○ Extensible control plane
● Lots of details, hard to be managed
directly
○ Hundreds of lines of manifests

Deploy Pulsar Clusters on K8s
● Helm is a tool for managing Kubernetes
packages
○ Chart
■ Pulsar
○ Config
○ Release
● Works for day-1 operations
○ What about days after?

Operations After “Day-1”
● It’s difficult to manage the entire lifecycle of Pulsar Clusters with Helm charts
automatically
○ Upgrades
○ Scale up/down
○ Failover
○ Fine-grained, complex workflows
● Requires some program to perform these operations based on the state of
Pulsar clusters continuously

Pulsar Operators
● StreamNative developed a set of Pulsar operators to automate common
operational activities
○ Put operational knowledges of Pulsar clusters in softwares
○ Let software manage softwares
● Fundamental elements
○ CRDs
○ Controllers

Pulsar Operators: CRDs
● CRD: Custom Resource Definition
● Declarative APIs
○ Different CRDs for different component clusters
■ ZooKeeper
■ BookKeeper
■ PulsarBroker
■ PulsarProxy
○ Treat a cluster as a single object rather than a set of primitives directly(like Pod, StatefulSet,
Service, etc.)
■ Metadata
■ Spec
● Defines the desired state
■ Status
● Exposes the actual state

Example

Enable Advanced Features

Pulsar Operators
● Controllers: encode operational knowledges into programs
○ Reconcile the actual state towards the desired state continuously
■ Resilient: level-based reconciliations
■ Eventually consistent
○ Triggered by events
■ Changes of resources
■ Timer
■ Custom event source
● Allow customized management workflow on resources flexibly

Pulsar Operators

Controlled Cluster Upgrades
● Upgrade clusters smoothly in a controlled manner
○ Maintain cluster availability
○ Avoid data-loss
○ Minimum impacts
● Rolling upgrade in K8s?
○ Not good enough for stateful workloads
■ BookKeeper
● Data re-replication during upgrades
■ ZooKeeper
● Leader restart could cause system to be unavailable for a few seconds

ZooKeeper Upgrades
● Use `OnDelete` update
strategy to control the
sequence of upgrades
● Collect membership
information via Rest APIs
● Upgrade ZooKeeper Leader
node after follower nodes to
reduce impacts

BookKeeper Upgrades
● Turn off auto-recovery during
upgrades to avoid unnecessary
data re-replication
● Turn on auto-recovery after
upgrades automatically

Decommission Bookies
● Decommissioning bookies from a BookKeeper cluster is a complex and
error-prone operation
○ Admin has to perform the following steps for each bookie to decommission
■ Run $ bin/bookkeeper shell listunderreplicated to see if there is under replicated
ledgers
■ Stop the bookie if there is no under-replicated ledgers
■ Run $ bin/bookkeeper shell decommissionbookie -bookieid <target bookieid> to
decommission the target bookie
● Replicate under-replicated ledgers
● Remove bookie metadata

Decommission Bookies by Operator
● Operator is able to decommission bookies automatically
○ The administrator just need to update the value of replicas to the desired number, operator
then take care of the decommission workflow
● How it works
○ Add a finalizer to each bookie pod for pre-deletion hook
○ Create a job to decommission the bookie on pod deletion
○ Remove the finalizer on the pod to after decommission

Decommission Bookies by Operator

Scale Down Bookies by Operator
● Scale down from 6 -> 3
○ Operator controlled decommissioning
by one bookie pod at a time

● Create a job to decommission
the bookie

● Remove the finalizer on the pod
when the decommissioning job
completes successfully
○ The job will be garbage collected

● Keep decommissioning until the
number of replicas reaches the
expected value

Cleanup After Cluster Deletion
● Sometimes the metadata and
the data of a broker cluster need
to be deleted explicitly after the
deletion of the cluster
○ A shared storage architecture

Cleanup After Cluster Deletion

Helm Chart Integration
● StreamNative platform provides a Helm chart for managing pulsar clusters
with operators
○ Use cases
■ Deploy a new pulsar cluster mostly just like using the open-source Helm chart
■ Help users to migrate existing pulsar clusters from Helm charts to operators
○ Map the configuration of helm releases to definitions of operator CRDs
○ Operators control the clusters under the hood

Upgrade from Helm Chart

Conclusion
● Operators are powerful tools for managing lifecycles of pulsar clusters in
production on Kubernetes
○ Especially for operations after “Day-1”
● It evolves with Pulsar and will be made it better and better
○ Built-in structured configurations
○ Fine-grained automatic cluster management
● Want to try it out?
○ StreamNative Platform
○ StreamNative Cloud

StreamNative Platform
Self-managed enterprise offering of Pulsar
✓ Kafka-on-Pulsar
✓ Function Mesh for serverless streaming
✓ Enterprise-ready security
✓ Pulsar Operators
✓ Seamless StreamNative Cloud
experience
https://streamnative.io/platform

StreamNative Cloud
Fully-managed Apache Pulsar-as-a-Service
✓ Massive scale without the ops overhead
✓ Built for hybrid and multi-cloud
✓ Cloud-Hosted & Cloud-Managed
✓ Stream across public clouds for
multi-cloud applications
✓ Elastic, consumption-based pricing with
‘pay as you go’ model
✓ Reliably scale mission-critical apps
https://streamnative.io/cloud

We’re hiring
Build Pulsar with the team that builds Pulsar
✓ Work with the creators of Pulsar
✓ Exciting, growth-stage company
✓ Open and collaborative environment
✓ Competitive compensation and
beneﬁts
✓ Best teammates on earth
https://streamnative.io/careers

Thanks!

Manage Pulsar Cluster Lifecycles with Kubernetes Operators - Pulsar Summit NA 2021

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Manage Pulsar Cluster Lifecycles with Kubernetes Operators - Pulsar Summit NA 2021