Organisations are building their applications around microservice architectures because of the flexibility, speed of delivery, and maintainability they deliver.
Want to try out MongoDB on your laptop? Execute a single command and you have a lightweight, self-contained sandbox; another command removes all trace when you're done. Need an identical copy of your application stack in multiple environments? Build your own container image and then your entire development, test, operations, and support teams can launch an identical clone environment.
Containers are revolutionizing the entire software lifecycle: from the earliest technical experiments and proofs of concept through development, test, deployment, and support. Orchestration tools manage how multiple containers are created, upgraded and made highly available. Orchestration also controls how containers are connected to build sophisticated applications from multiple, microservice containers.
This presentation introduces you to technologies such as Docker, Kubernetes & Kafka which are driving the microservices revolution. Learn about containers and orchestration – and most importantly how to exploit them for stateful services such as MongoDB.
13. #MDBW16
Alternate Microservices Example
• Much larger Microservices
1. User Account
2. Product Catalog
3. Inventory
4. Orders
• Best practice is each
microservice has its own
database
14. Conway’s Law
1967
Any organization that designs a system will
inevitably produce a design whose structure
is a copy of the organization's
communication structure.”
19. #MDBW16
VMs vs. Containers
VM VMVM
Bare Metal
Host Operating System
Hypervisor
Guest OS
Libraries
Apps
Service
Guest OS
Libraries
Apps
Service
Guest OS
Libraries
Apps
Service
Container ContainerContainer
Bare Metal
Host Operating System
Docker Engine
Libraries
Libraries
Apps
Libraries
Apps
Service ServiceService
20. #MDBW16
VMs vs. Containers
VM VMVM
Bare Metal
Host Operating System
Hypervisor
Guest OS
Libraries
Apps
Service
Guest OS
Libraries
Apps
Service
Guest OS
Libraries
Apps
Service
Container ContainerContainer
Bare Metal
Host Operating System
Docker Engine
Libraries
Libraries
Apps
Libraries
Apps
Service ServiceService
21. #MDBW16
VMs vs. Containers
VM VMVM
Bare Metal
Host Operating System
Hypervisor
Guest OS
Libraries
Apps
Service
Guest OS
Libraries
Apps
Service
Guest OS
Libraries
Apps
Service
Container ContainerContainer
Bare Metal
Host Operating System
Docker Engine
Libraries
Libraries
Apps
Libraries
Apps
Service ServiceService
22. #MDBW16
Docker
• Simple to use
• 100K+ images on Docker Hub
• Build images from images
• Platforms
• Linux, OS X, Windows
• Laptop, VM, Cloud,…
• Cloud services
35. #MDBW16
Kubernetes
Created by Google, feature-rich and
widely adopted
• Deployment and ‘replication’
• On-line scale out/in
• Rolling upgrades
• High Availability
• Persistence
• Ports
• Load balancing
• Google Compute Engine
36. #MDBW16
Apache Mesos
10,000s of physical servers;
used by Twitter, Airbnb & Apple
• Code (“frameworks) vs.
declarative
• Less feature rich than
Kubernetes
• Kubernetes as a Mesos
framework
• Foundation for distributed
37. #MDBW16
Choosing an Orchestration Framework
• What you have:
• Skills?
• DevOps frameworks?
• Number of hosts?
• Bare metal, VMs, or cloud?
• Lifecycle
• Features
• Automated High Availability?
• Grouping and load balancing?
• As a service??
47. #MDBW16
References
• Enabling Microservices – Containers & Orchestration Explained
https://www.mongodb.com/collateral/microservices-containers-and-
orchestration-explained
• Microservices: The Evolution of Building Modern Applications
https://www.mongodb.com/collateral/microservices-the-evolution-of-building-
modern-applications
• Data Streaming with Apache Kafka & MongoDB
https://www.mongodb.com/collateral/data-streaming-with-apache-kafka-and-
mongodb
Editor's Notes
1 + 10
Microservice architectures implement applications as a series of small, self-contained, loosely coupled software components. Each has a specific and well understood role.
Web & Mobile Apps => Enterprise
Micro Web Services
Microservices were pioneered in the web and then mobile App worlds; at one time called micro-web-services. Now other enterprises are looking for the same benefits.
Microservice architectures implement applications as a series of small, self-contained, loosely coupled software components. Each has a specific and well understood role.
Benefits of microservices:
- Development Speed
- Rapid Iteration
Evolve quickly, continuous deployment
Isolate impact of changes to existing functions or just add a new one
Reactive development
Maintainable
Independent, empowered work teams
Spaghetti Code
Reverse engineer?
No one understands entire code base
Change one line of code, impacts scores of other, unexpected places
Monolith is like Spaghetti
Changing anything impacts everything else.
<= 1990s
Pre-SOA (monolithic)
Tight coupling
For a monolith to change, all must agree on each change. Each change has unanticipated effects requiring careful testing beforehand
Easier to remove or change a piece but still need to make sure that it fits back together properly
SOA was billed as a way of delivering code re-use but people ended up designing for efficiency instead.
Service Oriented Architecture is like a Pie
Easier to remove or change a piece but still need to make sure that it fits back together properly
2000s
Traditional SOA
Looser coupling
Elements in SOA are developed more autonomously but must be coordinated with others to fit into the overall design
SOA was billed as a way of delivering code re-use but people ended up designing for efficiency instead.
Add a new flavor independently.
Chef making chocolate knows that well but need not know the others
Blueberry goes out of fashion, remove them
Need more green cakes, add them
Improved pink frosting, throw out the old ones and the new ones.
Microservices are like Cupcakes
Can add new ones with different flavors, remove ones that you no longer need, add more pink ones if there’s greater demand
Developers can create and activate new microservices without prior coordination with others. Their adherence to MSA principles makes continuous delivery of new or modified services possible
Greater modularity, looser coupling.
Started in the web and mobile app world, moving to Enterprise. Big in media and startups
Plan for flexibility rather than reuse
Each of the ovals represents a microservice.
Each source of social media feeds has its own microservice which is specialised in interfacing with the relevant API.
Each of those microservices passes messages to the ‘feed merge’ microservice which can then make them available for further microservices to work with.
Communication between the microservices is over the network – they can be local to the same machine or distributed.
Best practice is for each microservice to be stateless and to have its own database or schema
Individual microservices can be updated in isolation or even removed if their role is no longer needed
When a new role (or even a change to an existing one) appears, best practice is to implement a new microservice rather than extending an existing one.
When a new role (or even a change to an existing one) appears, best practice is to implement a new microservice rather than extending an existing one.
Microservices allow scale-out.
Each type of microservice can be scaled independently – add extra instances just for the functions that are being overworked.
Multiple instances of each service can provide High Availability
An alternate view is that each microservice is much larger
The size will depend on your app and org.
What do you need to scale?
How is your org aligned?
– in this case User Account, Product Catalog, Inventory & Order. The key is to do what makes sense for your enterprise: which pieces need scaling independently, which would you like to upgrade independently, how does it fit into your organisation?
Functions are decoupled into four separate services (separate WAR files) and organized by business boundaries
Web pages, Classes, Config files to a service are grouped together
Services can evolve and iterate independently as each team can develop, test, and deploy code separately
Best practice is for each microservice to have its own database.
Melvin Edward Conway is a computer scientist, computer programmer, and hacker who coined what's now known as Conway's Law in 1967.
If the parts of the organization do not closely reflect the essential parts of the product, or if the relationship between organizations do not reflect relationship between product parts, than the project will be in trouble
-Organizations design systems which copy the organization
-If the parts of the organization do not closely reflect the essential parts of the product, or if the relationship between organizations do not reflect relationship between product parts, than the project will be in trouble
-Make sure the organization is compatible with the product architecture
Size.
Ownership
Netflix Cloud Native approach => grow org
Best practice is for each microservice to be small enough that a single developer should be able to understand its entire codebase (think in hundreds rather than 10,000s of lines of code).
The code for a microservice should be owned by the organization responsible for that function; for example the marketing development team should own the microservice responsible for sending nurture track emails.
Netflix was one of the pioneers of Microservices with their ”Cloud Native” approach – it was really all about being able to scale their development organisation.
10+10
Real world shipping containers
Same container efficiently transports goods by road, rail, and sea
Contents remain untouched through all those environments; no repacking needed
Ubiquitous and standardized
Simple to use – open, fill, close
Contents of each container safe from the others
Know how much space the container consumes
Software containers
Build an image containing the full application stack only once
Spin up many containers from the same image in multiple environments
Laptop, data center, cloud
Development, QA, production, support
Simple to use & efficient
Contents of each container isolated from the others
Storage, memory, namespace
Constrain resources available to each container
Storage, memory, CPU, IO
The most popular container technology
Simple to use and has a rich ecosystem
100,000+ images available from Docker Hub
Including mongo hub.docker.com/_/mongo/
Syncs with GitHub projects
Define new images built upon base images
Define interfaces between containers
LINUX, (and now) Windows, and OS X
Runs on bare metal, VMs, and cloud. Cloud providers supply the Docker infrastructure (e.g. Google Container Engine)
Normal rules still apply
Containers provide opportunities to improve security
Containers provide isolation; resources can only be accessed from outside through explicitly provided APIs
Resources can be rationed
A container’s role can be very narrow – remove anything not required
Images and containers should be kept current; rolling upgrades with Kubernetes or Aurora
Typically log into container as root so restrict access
A single container can be interesting and useful.
O2 Arena
Microservices built by combining multiple containers
Build sophisticated services from many small, focused processes (containers)
Well defined APIs between components
Each component can use different libraries, middleware & programming languages
Modular, decoupled architecture simplifies maintenance and enables reuse
Fault tolerant
Scalable
To do useful work, microservices need a way of communicating – Apache Kafka
Kafka provides a flexible, scalable, and reliable method to distribute streams of event data from one or more **producers** to one or more **consumers**.
Examples of **events** (or **messages**) include:
A periodic sensor reading such as the current temperature
A user adding an item to the shopping cart in an online store
A Tweet being sent with a specific hashtag
A log entry generated for each click in a web application
Streams of Kafka events are organized into **topics**. A producer chooses a topic to send a given event to and consumers select which topics they pull events from. For example, a financial application could pull NYSE stock trades from one topic, and company financial announcements from another in order to look for trading opportunities.
Kafka actually stores all of the messages that it passes around – this makes it ideal for production microservice deployments
A microservice can be upgraded and then catch up on everything it missed
Or even apply its updated business logic to the full history of events
A new microservice can be added and it can be brought up to speed with everything that’s gone before
If one service is generating more work than another can keep up with then Kafka operates as a buffer
To do useful work, microservices need a way of communicating – Apache Kafka
Kafka provides a flexible, scalable, and reliable method to distribute streams of event data from one or more **producers** to one or more **consumers**.
Examples of **events** (or **messages**) include:
A periodic sensor reading such as the current temperature
A user adding an item to the shopping cart in an online store
A Tweet being sent with a specific hashtag
A log entry generated for each click in a web application
Streams of Kafka events are organized into **topics**. A producer chooses a topic to send a given event to and consumers select which topics they pull events from. For example, a financial application could pull NYSE stock trades from one topic, and company financial announcements from another in order to look for trading opportunities.
Kafka actually stores all of the messages that it passes around – this makes it ideal for production microservice deployments
A microservice can be upgraded and then catch up on everything it missed
Or even apply its updated business logic to the full history of events
A new microservice can be added and it can be brought up to speed with everything that’s gone before
If one service is generating more work than another can keep up with then Kafka operates as a buffer
To do useful work, microservices need a way of communicating – Apache Kafka
Kafka provides a flexible, scalable, and reliable method to distribute streams of event data from one or more **producers** to one or more **consumers**.
Examples of **events** (or **messages**) include:
A periodic sensor reading such as the current temperature
A user adding an item to the shopping cart in an online store
A Tweet being sent with a specific hashtag
A log entry generated for each click in a web application
Streams of Kafka events are organized into **topics**. A producer chooses a topic to send a given event to and consumers select which topics they pull events from. For example, a financial application could pull NYSE stock trades from one topic, and company financial announcements from another in order to look for trading opportunities.
Kafka actually stores all of the messages that it passes around – this makes it ideal for production microservice deployments
A microservice can be upgraded and then catch up on everything it missed
Or even apply its updated business logic to the full history of events
A new microservice can be added and it can be brought up to speed with everything that’s gone before
If one service is generating more work than another can keep up with then Kafka operates as a buffer
To do useful work, microservices need a way of communicating – Apache Kafka
Kafka provides a flexible, scalable, and reliable method to distribute streams of event data from one or more **producers** to one or more **consumers**.
Examples of **events** (or **messages**) include:
A periodic sensor reading such as the current temperature
A user adding an item to the shopping cart in an online store
A Tweet being sent with a specific hashtag
A log entry generated for each click in a web application
Streams of Kafka events are organized into **topics**. A producer chooses a topic to send a given event to and consumers select which topics they pull events from. For example, a financial application could pull NYSE stock trades from one topic, and company financial announcements from another in order to look for trading opportunities.
Kafka actually stores all of the messages that it passes around – this makes it ideal for production microservice deployments
A microservice can be upgraded and then catch up on everything it missed
Or even apply its updated business logic to the full history of events
A new microservice can be added and it can be brought up to speed with everything that’s gone before
If one service is generating more work than another can keep up with then Kafka operates as a buffer
To do useful work, microservices need a way of communicating – Apache Kafka
Kafka provides a flexible, scalable, and reliable method to distribute streams of event data from one or more **producers** to one or more **consumers**.
Examples of **events** (or **messages**) include:
A periodic sensor reading such as the current temperature
A user adding an item to the shopping cart in an online store
A Tweet being sent with a specific hashtag
A log entry generated for each click in a web application
Streams of Kafka events are organized into **topics**. A producer chooses a topic to send a given event to and consumers select which topics they pull events from. For example, a financial application could pull NYSE stock trades from one topic, and company financial announcements from another in order to look for trading opportunities.
Kafka actually stores all of the messages that it passes around – this makes it ideal for production microservice deployments
A microservice can be upgraded and then catch up on everything it missed
Or even apply its updated business logic to the full history of events
A new microservice can be added and it can be brought up to speed with everything that’s gone before
If one service is generating more work than another can keep up with then Kafka operates as a buffer
20+5
Automated deployment, connecting, and maintenance of multiple containers
Provision hosts
Instantiate containers
Reschedule failed containers
Link containers through defined interfaces
Expose services to the outside world
Scale out and back in
Created by Google, feature-rich and widely adopted
Automated container deployment and ‘replication’
On-line scale out/in
Rolling upgrades
HA – automatic rescheduling of failed containers
Exposure of network ports to external apps
Load balancing over groups of containers providing a service
Provided as a service by Google Compute Engine
Designed to scale to 10,000s of physical servers; used by Twitter, Airbnb & Apple
Developer writes code to turn application into a framework to run on Mesos
Less feature rich than Kubernetes; considers many functions such as load balancing, rescheduling, and scaling to be a higher level function
Project exists to run Kubernetes as a Mesos framework
Foundation for distributed systems
Apache Aurora, Chronos, Marathon
Don’t forget Docker Compose
Factors to consider…
Integration with existing DevOps frameworks?
Number of hosts?
Bare metal, VMs, or cloud deployment?
Automated High Availability?
Grouping and load balancing?
Existing skills?
Install your own orchestration framework or use as a service?
25+7
Moving parts; Orchestration doesn’t monitor
Agility
DB per microservice
Monitoring & automation
You have lots of moving parts in a microservice architecture – need to monitor and automate as much as possible
Flexible data model
Fits in with the need to be agile
Redundancy
MongoDB replica sets -> can perform online upgrades and easily cope with rescheduling
Scalability
MongoDB sharding lets your database scale just as easily as your stateless microservices
Remember web-scale?
Best practice for each service to have its own schema or database; MongoDB’s simplicity helps
Kubernetes not designed for stateful services
3 choices:
MongoDB outside of container (Atlas?)
Kubernetes manages MongoDB
Kubernetes manages Ops Manager agent; Ops/Cloud Manager manage MongoDB
Orchestrating MongoDB containers requires special treatment as it’s a distributed, stateful application…
State should survive rescheduling; use Kubernetes’ persistent volumes abstraction
Replica Set members must communicate with each other; expose external IP addresses/ports which survive rescheduling
Replica Set must be initialized from exactly one member
MongoDB must still be monitored and backed up – MongoDB Cloud Manager
Kubernetes.
Single Pod/comtainer/mongod in a ReplicationController.
Use external IP addresses (other IP addresses & hostnames are local to Kubernetes cluster and they change)
Refer to white paper for details
32+3
Fast > Elegant
Sagrada Familia –1882-2026 (144 years).
Frequent, localised changes
Localised scaling
Upgrades
Only if:
Scaling team
Designing for change
Fast is more important than elegant.
Change in the application’s functionality and usage is frequent.
Change occurs at different rates within the application, so functional isolation and simple integration are more important than module cohesiveness.
Functionality is easily separated into simple, isolatable components.
When you have the developer/DevOps skillsets.
Where development org boundaries match service boundaries.
Don’t forget that you’re building a distributed system -> complexity but there are precedents to read up on.
One argument is that you shouldn’t bother with microservices unless you need either:
- Scale your team
- Design for change
Sagrada Familia – designed by Gaudi; construction started on March 19, 1882. Expected to be finished in 2026.
35+5
Gap (flexibility): Monolith -> microservice (75 days). New types of PO took just days
FuboTV (scalability). Single cluster for dev, QA + production. Cope with 100x bursts. Run MongoDB on Kubernetes
Otto (arch == org). Fast, iterative delivery
Backcountry (> distributed dev team): Schema changes were taking 20% of dev time. Flexible schema
Compare The Market (Use Docker, Kafka, MongoDB & Ops Manager).
GAP moved their purchase order system from a monolith architecture to microservices. Due to MongoDB’s flexible schema, it took just 75 days to build the new system. When requirements changed and they had to add new types of purchase orders, it took days instead of months.
FuboTV is a North American soccer streaming service. Using Microservices with Kubernetes, Docker & MongoDB. Isolation means that they can use a single cluster of machines (in Google Cloud) for dev, QA & production. Very birsty application – scalability lets them handle 100x increases in traffic.
Otto – the key was to have an architecture that fits with their organization. Microservices empower loosely couple development teams (business, project management, IT). This is all enabling Fast test & deployment + Iterative, Continuous Delivery
Backcountry.com is an online specialty retailer that sells outdoor clothing and gear. The driver to Microservices for them was a growing, distributed development team. As more and more developers joined and made contributions to the code, the schemas became convoluted and harder to maintain; contributing to 20% of the Scrum backlog. Taking advantage of MongoDB’s flexible data model, Backcountry was able to iterate faster, reduce development time, and mitigate technical debt.
Compare The Market: In the cloud, each microservice, or logical grouping of related microservices, is provisioned with its own MongoDB replica set running in Encrypted storage engine to further reduce our security-related surface area. Use Docker, Kafka & MongoDB.