Apache Pulsar FAQ
Guidance for IT leaders evaluating enterprise messaging
Apache Pulsar FAQ
Guidance for IT leaders evaluating enterprise messaging
Apache Pulsar FAQ
Guidance for IT leaders
Apache Pulsar is an open-source messaging and event streaming platform increasingly used to power real-time data systems. As organizations evaluate Pulsar for enterprise use, they encounter architectural nuances, deployment decisions, and support tradeoffs. This FAQ offers straight answers based on what we hear from platform teams daily—and includes guidance based on Dattell’s experience supporting Pulsar in production.
What is Apache Pulsar?
Apache Pulsar is a distributed messaging and event streaming system developed originally at Yahoo and now maintained by the Apache Software Foundation. It supports publish/subscribe and queuing patterns, long-term message storage, and multi-tenant architectures—making it a strong fit for scalable, real-time systems.
→ Learn more about Apache Pulsar consulting and support from Dattell.
How is Pulsar different from Apache Kafka?
While both Pulsar and Kafka are distributed messaging systems, Pulsar introduces a distinct architecture:
Separation of compute and storage – Pulsar brokers are stateless, while Apache BookKeeper handles message storage.
Built-in geo-replication – Pulsar natively supports cross-region replication.
True multi-tenancy – Namespace-based isolation is built into Pulsar from day one.
→ See our comparison of Kafka and Pulsar to understand when switching makes sense.
Is Pulsar truly cloud-native?
Pulsar is often described as cloud-native—but that depends on how the term is defined.
Pulsar brokers are stateless and scale well in cloud environments.
However, BookKeeper and ZooKeeper are stateful and do not scale dynamically without careful coordination.
Teams should be wary of claims that Pulsar can “scale up and down instantly.” Stateless components like brokers can—but the full system cannot without planned effort.
→ We clarify this in detail in our article: Common Pulsar misconceptions: scale, state, and cloud-native claims.
Can Pulsar scale up and down automatically?
Pulsar brokers can scale elastically, which is useful for handling traffic spikes. However, BookKeeper and ZooKeeper are stateful and must maintain consensus and replication. These components:
Do not support automatic horizontal scaling
Require time to rebalance when adding/removing nodes
Must be scaled carefully to avoid data loss or cluster instability
→ Our Pulsar architecture consulting helps teams design right-sized deployments that scale effectively without unexpected costs or downtime.
What components make up a Pulsar deployment?
Broker: Stateless messaging router
Apache BookKeeper: Write-ahead storage engine
Apache ZooKeeper: Metadata and coordination service
To operate Pulsar in production, all three components must be configured, monitored, and maintained.
→ Check out our deep dive into the fundamentals of Apache Pulsar. Additionally, we have an introductory course that explains the basics of Apache Pulsar and guides users through a sample project.
How does Pulsar handle data retention?
Pulsar supports configurable message retention policies per topic or namespace. It allows:
Infinite or time-bounded retention
Topic compaction for “latest value” message patterns
Tiered storage integrations for long-term data archiving (e.g., to S3)
→ We help teams implement retention policies that balance cost and performance. Ask us about long-term Pulsar storage architecture.
What are Pulsar Functions?
Pulsar Functions are lightweight compute components that allow you to process messages in-line—no separate processing framework required. They’re useful for transformations, filtering, or simple analytics tasks at the edge of your stream.
→ For larger workloads, we also help teams integrate Pulsar with Flink, Spark, or custom microservices.
How secure is Pulsar?
Apache Pulsar supports:
TLS for data-in-transit encryption
OAuth2, mutual TLS, and token-based authentication
Role-based authorization (via Pulsar’s built-in ACL system)
Fine-grained access controls per namespace, topic, or role
→ Dattell includes Pulsar security hardening in our onboarding packages. Learn more here.
What kind of support does Pulsar have?
Production deployments often require:
24×7 support
SLA-backed uptime guarantees
Proactive monitoring
Fast response to failures
→ Dattell offers enterprise Pulsar support with flat-rate pricing, 99.99% uptime guarantees, 24×7 monitoring & on-call, and 15-minute response times.
Does Pulsar support multi-tenancy?
Yes—Pulsar is one of the only major messaging platforms with first-class multi-tenancy support. You can create isolated namespaces per team, application, or environment with:
Independent quotas
Separate authentication policies
Dedicated topics and storage
→ We’ve helped organizations roll out Pulsar to support dozens of internal tenants on a shared cluster.
What are common deployment challenges with Pulsar?
Teams often encounter issues such as:
Cluster initialization errors: Misconfigurations can lead to broker initialization failures.
Resource constraints: Inadequate memory or CPU resources can cause performance bottlenecks.
Proper planning and resource allocation are crucial for a stable deployment.
How can I monitor Pulsar's performance effectively?
Effective monitoring involves:
Real-time metrics: Tracking throughput, latency, and resource utilization.
Alerting mechanisms: Setting up alerts for anomalies or threshold breaches.
Implementing robust monitoring tools ensures system health and performance.
What are best practices for scaling Pulsar clusters?
Scaling strategies include:
Horizontal scaling: Adding more brokers and bookies to handle increased load.
Partitioning topics: Distributing messages across partitions to balance the load.
Regularly reviewing and adjusting configurations helps maintain optimal performance.
How does Pulsar handle message retention and backlog?
Pulsar allows configuring:
Retention policies: Determining how long messages are stored after acknowledgment.
Backlog quotas: Setting limits on unacknowledged messages to prevent resource exhaustion.
Proper configuration ensures efficient storage management.
How can I troubleshoot common Pulsar errors?
Common troubleshooting steps include:
Checking logs: Reviewing broker and bookie logs for error messages.
Validating configurations: Ensuring settings are correctly applied.
Consulting documentation: Referring to official guides for known issues and solutions.
Timely troubleshooting helps maintain system reliability. Dattell offers enterprise Pulsar support with 99.99% uptime guarantees, 24×7 troubleshooting, and 15-minute response times.
Where can I learn more about Apache Pulsar?
Book a consult to explore managed Pulsar options
Enterprise-grade Pulsar support.
No licensing games. No surprises.
Visit our Managed Pulsar page or complete the form below for more information.
- 99.99% uptime guarantee
- 15-minute response times
- 24x7 monitoring & on-call
Enterprise-grade Pulsar support.
No licensing games. No surprises.
Visit our Managed Pulsar page or complete the form below for more information.
- 99.99% uptime guarantee
- 15-minute response times
- 24x7 monitoring & on-call
Enterprise-grade Pulsar support.
No licensing games. No surprises.
Visit our Managed Pulsar page or complete the form below for more information.
- 99.99% uptime guarantee
- 15-minute response times
- 24x7 monitoring & on-call